Search Results

Is the euphoria produced by exercise mediated by opioid receptors or cannabinoid receptors? The endorphin rush The endorphin rush is an expression widely used in popular culture that refers to feelings of euphoria, elation, endurance, and decreased anxiety and pain supposedly caused by the release of endorphins in the brain. The endorphin rush has sunk deep roots in the popular culture. There are drinks and rock bands named after it. It is considered responsible for increasing the performance of athletes, the pleasure of sex and even “sub space”—an altered state of consciousness produced by pain in masochists. The runner’s high But the most well-known example of an endorphin rush is the runner’s high. A marathon runner is about to hit the wall. His energy is depleted, he is exhausted, and his legs are about to give up. But, all of a sudden, something magical happens. He feels full of energy and can complete the race, running even faster. All the anxiety is gone and, in fact, he feels totally happy. What happened? Well, his brain resorted to a last-resort trick. It released a bunch of endorphins that relieved his fatigue and made him high. That was the story that we have been told for a long time. But now it turns out that it may not be the endorphins after all, but some marihuana-like compounds called endocannabinoids. This article looks at the evidence for both explanations. In the process, it will explain some interesting facts about the brain and the methods that scientists use to explore it. Endorphins and opioid receptors “Endorphins” is the name popularly given to endogenous opioids, a large family of peptides found in the brain and the blood that are able to activate the opioid receptors used by drugs like morphine, heroin, fentanyl and codeine. There are three classic opioid receptors, designated by the Greek letters mu, delta and kappa. A fourth receptor and its corresponding peptide were discovered simultaneously by two groups, so it was given the two names that they used: the nociceptin/orphanin receptor. However, this receptor does not produce euphoria or analgesia, so I will leave it out of this discussion. Endorphins are peptides encoded by three genes: proopiomelanocortin (POMC), proenkephalin and prodynorphin. If Nature was well-organized and rational, each of these genes would encode a peptide that would activate each of the three classic opioid receptors, and that would be that. Alas! Nature is neither simple nor rational. In fact, it displays a perverse penchant to make things convoluted. And so each gene encode for a complex mixture of peptides: enkephalins, dynorphins and beta-endorphin. To make things even more fun, the POMC gene also encodes for two peptides that have nothing to do with opioids and their receptors. One is alpha-melanocyte-stimulating hormone (alpha-MSH), which regulates appetite and sexual behavior. The other is adrenocorticotropic hormone (ACTH), which is part of the stress response of the hypothalamus-pituitary-adrenal (HPA) axis. See? I told you Nature was devious. So, let’s try to keep things simple for this discussion. Enkephalins and beta-endorphin bind to mu and delta opioid receptors, that produce analgesia and euphoria. Dynorphin binds to kappa receptors that produce analgesia and dysphoria—the opposite of euphoria. Measuring endorphins in the blood or the saliva is meaningless Initial studies on the runner’s high measured endorphin in the blood or the saliva of runners, and found that running and other types of exercise increased them. However, this is meaningless. Endorphins do not cross the blood-brain barrier, a wall in the capillaries of the brain that makes its chemical environment totally different from that of the blood. So endorphins in the blood cannot induce euphoria or analgesia, because these effects are produced by neurons in the brain. On top of that, endorphins (mainly the beta-endorphin encoded by the POMC gene) are released into the blood from the pituitary gland at the same time as ACTH, which is also encoded by the POMC gene. Since ACTH release is part of the stress response, endorphin in the blood does not produce euphoria. In fact, when endorphins are released in some parts of the brain (the locus coeruleus), they turn off the stress response. Hence, to determine if the runner’s high is mediated by endorphins, we need to measure them in the brain of the runners. A study of endorphin release in the brain of runners Measuring endorphins in the brain of humans while they are awake—in fact, shortly after they performed a strenuous exercise—may seem like an impossible task. However, it can be done by using a fancy technique called positron emission tomography (PET). PET uses drugs that incorporate unstable isotopes like fluor-18 (18F) or carbon-11 (11C). These drugs are called radiotracers. When the isotopes decay, they release a positron. It interacts with an electron, producing a gamma ray, which is detected by the PET machine. When the radiotracer drug is bound to a receptor, like the mu-opioid receptor, it stays longer in that brain region, which gives a brighter PET signal. However, if endorphins are released in that brain region, they displace the radiotracer from the receptor, so the PET signal decreases. This allows scientists to create images of the brain where endorphin release is color-coded and quantified. The first study that investigated the runner’s high with PET (Boecker et al., 2008) used as radiotracer [18F]FDPN, an opioid drug that binds to all the classical opioid receptors. The subjects were 10 male runners who had experienced the runner’s high before and trained for a minimum of 4 hours weekly for the last 2 years. These inclusion criteria were important because they ensured that the effects studied were really a runner’s high and not mere responses to exercise or fatigue. Thirty minutes after a two-hour run, the subjects received an injection of the radiotracer and had their brains scanned with PET. As control, they had a PET scan after 24 hours without exercise. These two PET scans were separated by 4 weeks and their order was randomized. The results were shown as endorphin release after running compared with rest for each subject. An increase in endorphins was found in the following brain regions: orbitofrontal cortex—a region of the prefrontal cortex that assigns value to actions, evaluates contingencies and appraises emotions; dorsolateral prefrontal cortex—involved in decision making, cognitive flexibility, working memory and planning; insula—an area of the cortex buried inside the brain hemispheres that is involved in pain, pleasure, euphoria and other emotions; anterior cingulate cortex—a region of the cortex between the hemispheres that controls motivation, detects errors and conflicts, and plans actions; posterior cingulate cortex—involved in spatial memory, emotional saliency and learning; sensory and motor cortex—involved in detecting sensations and directing muscle contraction, respectively. The runners were also given a psychological test to evaluate their emotions after running. Two emotions increased after running: happiness and euphoria. This indicated the presence of the runner’s high. Other emotions didn’t change after the run, including confusion, anger, sadness, fatigue, fear, energy and tension. Finally, the scientists analyzed both sets of data together to determine if there was a correlation between the feelings of euphoria and endorphin release in each brain area. A positive correlation between endorphin release and euphoria was found in the orbitofrontal cortex, dorsolateral prefrontal cortex, anterior and posterior cingulate cortex, insula, sensory cortex and motor cortex. These results strongly support the idea that the runner’s high is a feeling of euphoria caused by endorphin release in brain areas that process emotions and direct actions. Endorphin release in the brain during moderate and intense exercise Ten years later, another study (Saanijoki et al., 2018) used PET scanning to find out if moderate and intense exercise are equally able to induce endorphin release. Another difference with the previous PET study is that they used a radiotracer, [11C]carfentanil, that is a selective agonist of mu-opioid receptors. The previous study used [18F]FDPN, which could also bind to the kappa opioid receptors and therefore detect the release of dynorphins in addition to enkephalins and endorphins. Remember that dynorphins binding to kappa opioid receptors produce dysphoria, the opposite of what the endorphin high is supposed to be. But perhaps the most relevant differences were the subjects and the type of exercise. The 22 subjects were also men, but there was no requirement of them to have previously experienced the runner’s high or to exercise regularly. The exercise used in the experiments was not running, but indoor cycling. Moderate intensity exercise was defined as cycling for 1 hour “at workload in the middle between aerobic and anaerobic thresholds,” which were determined previously. High-intensity interval training (HIIT) consisted of five cycling sprints of 30 seconds at maximal load, separated by 4 minutes rests. They found that HIIT, but not moderate intensity exercise, induced endorphin release in many brain areas. Some were the same areas identified in the previous study: dorsolateral prefrontal cortex, orbitofrontal cortex, anterior and posterior cingulate cortex, thalamus and insula. In addition, they found endorphin release in the ventral striatum, hippocampus, cerebellum, amygdala and periaqueductal gray (PAG). The ventral striatum contains the ventral tegmental area (VTA) and the nucleus accumbens, which form the dopamine reward pathway that mediates motivation and drug addiction. The amygdala mediates fear and controls the stress response. The PAG is the beginning of a neuronal pathway that goes from the brainstem to the spinal cord and inhibits pain. Again, psychological tests were used to determine if the subjects had a runner’s high. They were taken by 12 subjects that did both types of exercise. Surprisingly, euphoria, motivation and satisfaction were higher during moderate-intensity exercise than during HIIT. Conversely, negative feelings like exhaustion, tension and irritation were higher during HIIT than during moderate exercise. Pain increased with exercise and it was not different between HIIT and moderate exercise. Even more unexpected was the finding that the negative feelings during HIIT correlated with endorphin release, particularly in the dorsal prefrontal cortex. Moreover, the euphoria produced by moderate exercise also correlated with endorphin release in the dorsal prefrontal cortex. So, there is no endorphin rush? This second study brought into question the idea of the endorphin rush. On the one hand, yes, exercise releases endorphins in the brain. And intense exercise releases more endorphins than moderate exercise. But, instead of being associated with euphoria and feelings of energy, which is the classic description of the runner’s high, endorphin release during intense exercise correlated with negative emotions like exhaustion and irritation. On top of that, moderate exercise produced euphoria and other positive feelings. All of these contrasts with the common description of the runner’s high, which is only achieved after hitting a wall of exhaustion during extreme exercise. So, endorphin release during intense exercise does not produce euphoria? There is no endorphin rush? The answer may be a bit more complicated. Maybe what happens is that endorphins are released during exercise as a compensatory response to negative feelings like pain, anxiety, irritation and exhaustion. With moderate exercise, they are able to eliminate these feelings and even produce euphoria. But with intense exercise, the negative feelings are so strong that endorphins cannot drown them. These negative feelings may be mediated by neuropeptides like dynorphins, corticotropin-releasing factor (CRF) and cholecystokinin (CCK). CRF drives the stress response of the HPA axis and the locus coeruleus. CCK induces anxiety and opposes the effects of endorphins. Mice do not have an endorphin rush Meanwhile, some scientists raised the possibility that the runner’s high was mediated by endocannabinoids instead of endorphins. Endocannabinoids are to cannabinoid receptors what endorphins are to opioid receptors. They are substances produced in the body that activate the same receptors as the psychoactive compounds in cannabis. The two main endocannabinoids are anandamide and 2-arachydonoyl-glycerol (2-AG). The high produced by marihuana is mediated by CB1 receptors, which are abundant in the brain. There are at least two other cannabinoid receptors, CB2 and GPR55, which do not mediate the psychotropic effects of cannabis but some of its other effects on the body. A study in mice (Fuss et al., 2015) showed that, when mice exercise on a running wheel, they have less anxiety and pain. They also had elevated levels of endocannabinoids in their blood. The analgesia produced by exercise was eliminated by blocking CB1 and CB2 receptors with their antagonists, but not by blocking opioid receptors with naloxone. This indicated that the pain reduction was mediated by endocannabinoids and not by endorphins. Similarly, the decrease in anxiety produced by exercise was blocked by antagonists of CB1 receptors, but not by antagonists of CB2 receptors or by naloxone. In a sophisticated experiment, the scientists selectively eliminated CB1 receptors in GABA-releasing neurons in the forebrain of mice using transgenic techniques. These mice ran less on the wheel than normal mice and lose the anxiolytic effect of running. This showed that the decrease in anxiety produced by wheel running in mice is mediated by CB1 receptors in forebrain neurons. However, this study does not tell us much about the runner’s high because its main characteristic is euphoria, and euphoria cannot be studied in mice. What it shows is that exercise decreases pain and anxiety in mice, and that these effects are mediated by the action of endocannabinoids in the forebrain. However, the analgesic and anxiolytic effects of cannabinoids have been known for a while. So, it’s not endorphins but the endocannabinoids? To see if endocannabinoids are responsible for the euphoria of the runner’s high, the same group performed their next experiments in humans (Siebers et al., 2021). The obvious experiment would be to repeat the first two studies with PET scanning, but with a radiotracer that binds to cannabinoid receptors instead of opioid receptors. Indeed, there are several radiotracers for CB1 receptors (Horti et al., 2006; Varlow et al., 2020; Hou et al., 2021). However, this study did not use them. Instead, they did three experiments. The first consisted of measuring endocannabinoids in the blood before and after exercise, which consisted of walking or running on a treadmill for 50 minutes. The second experiment consisted of a battery of psychological test to measure euphoria before and after the exercise. The subjects were injected with naltrexone, a mu-opioid receptor antagonist. If naltrexone decreased the euphoria, then it was mediated by endorphins. A more complete design would have used also CB1 receptors antagonists, like in the experiments with mice. Unfortunately, CB1 antagonists have not been authorized to be used in humans. Rimonabant, an antagonist of CB1 and CB2 receptors, was used in humans for a while, but withdrawn (Sam et al., 2011). The third experiment was a sophisticated way to measure anxiety, called the human elevated plus-maze. The subjects were made to walk on wooden planks forming a plus sign while wearing a virtual reality (VR) headset. In one direction (closed arm), the headset showed the planks surrounded by protective rock walls. In the other direction (open arm), the VR headset showed a 55 meter (180 feet) fall to either a river of icy water or a parking lot with cars. The time the subjects spent in the open arm was a measure of their anxiety levels. Both walking and running increased endocannabinoids in the blood, but running produced a larger increase than waking. Running, but not walking, produced euphoria. Naltrexone produced a small decrease in euphoria that was not statistically significant. As for the fancy experiment with the VR headset to measure anxiety, the results were rather meager. After running, the subjects experienced marginally less anxiety than after walking (p = 0.024). Naltrexone did not change the anxiety levels in either condition. This study was touted by the press as showing that the runner’s high is mediated by endocannabinoid and not by endorphins. Sensational news! People had been fooled into believing in the endorphin rush all along. My conclusion: it’s the endorphins, after all However, I have my doubts. The paper by Siebers et al. did not invalidate the two original studies using PET imaging to measure endorphin release in the brain. In fact, those two studies were of much higher quality than the one by Siebers et al. The two PET studies demonstrated the endorphins are released by exercise in brains areas relevant for controlling pain, mediating emotions and inducing euphoria. They were done by different groups and, in these measures, they were consistent which each other. The main thing in question is whether the endorphins released by exercise produce euphoria. In this, the two PET studies reached conflicting conclusions. The one by Boecker et al. showed that strenuous running produced euphoria. The one by Saanijoki et al. showed that only moderate exercise produced euphoria, which correlated with endorphin release. Intense exercise produced negative emotions, which also correlated with endorphin release. As I pointed out before, these results can be reconciled if we assume that endorphin release is a compensatory response that can reverse the negative emotions produced by moderate exercise, but not by intense exercise. But, what about the third study arguing that the euphoria is mediated by endocannabinoids? Its results are far from compelling. It showed only that the reduction is euphoria produced by naltrexone was not statistically significant—which is not the same as proving that naltrexone had no effect on euphoria. That would require a different statistical test, one that shows that euphoria with and without naltrexone is statistically the same. Hence, it is possible that naltrexone decreased euphoria, but this effect was not statistically significant due to the experimental design of this study. And it did not show that euphoria was caused by endocannabinoids, or that there was cannabinoid receptor activation in areas of the brain that mediate euphoria. The results of the anxiety tests by Siebers et al. were even less conclusive. The effect of running on anxiety was too small when compared to walking. A key control is missing: anxiety measures at rest. This should be compared with anxiety after walking. If we don’t have a clear decrease in anxiety produced by exercise, testing the effect of naltrexone on this small effect is meaningless. Endocannabinoids are released in the blood by exercise, for sure. But, although they cross the blood-brain barrier, this is not the same as endocannabinoids being released in brain areas that mediate euphoria, which is what the two PET imaging studies showed for endorphins. If we don’t know in which brain areas the endocannabinoids are released, we cannot propose a mechanism by which they induce euphoria. Besides, cannabinoids decrease anxiety, but they do not produce the high levels or euphoria induced by the opioid drugs and the endorphins. I think that the main source of confusion is the assumption that any strenuous exercise is going to automatically induce a runner’s high. This is not the experience of runners. The runner’s high is an altered state of consciousness that is encountered only by a selected group of runners after extremely long runs. It is probably a learned response. Only the first study (Boecker et al., 2008) selected runners who had already experienced the runner’s high and that said that they achieved that state during the experiment. The second study (Saanijoki et al., 2018) did not even select athletes who trained regularly. The third (Siebers et al., 2021) selected subjects who performed “endurance exercise more than twice a week,” but did not check if they experienced a runner’s high. My conclusion is that exercise releases endorphins and endocannabinoids. It induces a variety of positive and negative emotional states, mediated by euphoric (endorphins, endocannabinoids) and dysphoric (dynorphins, CRF, CCK) neurotransmitters. However, only in some special situations endorphin release raises to the level to produce the high euphoria seen in the runner’s high. The endorphin rush is not automatic. It seems to require entering some sort of trance state, or breaking through a neurophysiological barrier. References Boecker H, Sprenger T, Spilker ME, Henriksen G, Koppenhoefer M, Wagner KJ, Valet M, Berthele A, Tolle TR (2008) The Runner's High: Opioidergic Mechanisms in the Human Brain. Cerebral cortex (New York, NY : 1991). Fuss J, Steinle J, Bindila L, Auer MK, Kirchherr H, Lutz B, Gass P (2015) A runner's high depends on cannabinoid receptors in mice. Proceedings of the National Academy of Sciences 112:13105-13108. Horti AG, Fan H, Kuwabara H, Hilton J, Ravert HT, Holt DP, Alexander M, Kumar A, Rahmim A, Scheffel U, Wong DF, Dannals RF (2006) 11C-JHU75528: A Radiotracer for PET Imaging of CB1 Cannabinoid Receptors. Journal of Nuclear Medicine 47:1689-1696. Hou L, Rong J, Haider A, Ogasawara D, Varlow C, Schafroth MA, Mu L, Gan J, Xu H, Fowler CJ, Zhang MR, Vasdev N, Ametamey S, Cravatt BF, Wang L, Liang SH (2021) Positron Emission Tomography Imaging of the Endocannabinoid System: Opportunities and Challenges in Radiotracer Development. J Med Chem 64:123-149. Saanijoki T, Tuominen L, Tuulari JJ, Nummenmaa L, Arponen E, Kalliokoski K, Hirvonen J (2018) Opioid Release after High-Intensity Interval Training in Healthy Human Subjects. Neuropsychopharmacology 43:246-254. Sam AH, Salem V, Ghatei MA (2011) Rimonabant: From RIO to Ban. Journal of Obesity 2011:432607. Siebers M, Biedermann SV, Bindila L, Lutz B, Fuss J (2021) Exercise-induced euphoria and anxiolysis do not depend on endogenous opioids in humans. Psychoneuroendocrinology 126:105173. Varlow C, Boileau I, Wey HY, Liang SH, Vasdev N (2020) Classics in Neuroimaging: Imaging the Endocannabinoid Pathway with PET. ACS Chem Neurosci 11:1855-1862.

Several surveys found that nearly a majority of college students use choking during sex I strongly recommend not to practice choking. This article is part of a series intended to show that choking is unsafe, may cause brain damage, and is potentially lethal. Sexual choking is not exclusive of BDSM, and has become prevalent among the young. In a survey of 4,989 US college students, 58% of women had been choked during sex at least once (Herbenick et al., 2021). Another survey of undergraduate students (Herbenick et al., 2022a) found that 37% of the women and 7% of the men had been choked more than five times. Strangulation is also increasingly a feature of sexual assault. It is also used non-consensually during sex that was consensual up to that point. However, I will limit this discussion to consensual choking. Yet another survey of undergraduate and graduate students (Herbenick et al., 2022b) studied closely sexual choking in terms of prevalence, characteristics and physical responses. The survey was given to 13,449 students, of which 4,254 completed it. Men were 49.6% of the responders, women 48.1% and transgender/non-binary 2.2%. Age differences The survey found that 30% to 40% of the responders have practiced choking during sex. By comparing the responses of the older graduate students with the younger undergraduates, it found that choking is more prevalent among the young. The percentage of people doing the choking was 37.1% among the undergraduates and 27.6% among the graduate. The percentage of those being choked was 42.1% of the undergraduates and 32.1% of the graduates. Therefore, choking is more frequent in the younger generations, a sign that is increasing over time. Choking was less prevalent among people over 40 (Herbenick et al., 2023). Gender differences There were also substantial gender differences. Men did more choking (47.4% undergraduates, 37.7% graduates) than women (26.7% undergraduates, 16.2% graduates). Conversely, men were choked (25.4% undergraduates, 23.5% graduates) less frequently than women (57.6% undergraduates, 41.3% graduates). In transgender/non-binary people, choking (45.0%) and being choked (51.5%) were even more prevalent. In summary, men prefer to do the choking while women prefer to be choked. A majority of the women and transgender people in this sample have experienced choking. References Herbenick D, Fu TC, Patterson C (2023) Sexual Repertoire, Duration of Partnered Sex, Sexual Pleasure, and Orgasm: Findings from a US Nationally Representative Survey of Adults. J Sex Marital Ther 49:369-390. Herbenick D, Guerra-Reyes L, Patterson C, Rosenstock Gonzalez YR, Wagner C, Zounlome N (2022a) "It Was Scary, But Then It Was Kind of Exciting": Young Women's Experiences with Choking During Sex. Arch Sex Behav 51:1103-1123. Herbenick D, Patterson C, Beckmeyer J, Gonzalez YRR, Luetke M, Guerra-Reyes L, Eastman-Mueller H, Valdivia DS, Rosenberg M (2021) Diverse Sexual Behaviors in Undergraduate Students: Findings From a Campus Probability Survey. The journal of sexual medicine 18:1024-1041. Herbenick D, Fu TC, Eastman-Mueller H, Thomas S, Svetina Valdivia D, Rosenberg M, Guerra-Reyes L, Wright PJ, Kawata K, Feiner JR (2022b) Frequency, Method, Intensity, and Health Sequelae of Sexual Choking Among U.S. Undergraduate and Graduate Students. Arch Sex Behav. Copyright 2023 Hermes Solenzol.

Is it just to please a partner, for pleasure, or something else? I strongly recommend not to practice choking. This article is part of a series intended to show that choking is unsafe, may cause brain damage, and is potentially lethal. Many people finds been choked pleasurable In their survey of undergraduate and graduate students, the group of Herbenick (Herbenick et al., 2022b) found that 41.1% of the people who had been choked reported that choking was very pleasurable, 33.8% responded that it was somewhat pleasurable and 14.2% said that it was a little pleasurable. Only 3.1% said that choking was not pleasurable at all and didn’t want to repeat the experience, while 5.9% said it was not pleasurable but they would do it if their partners liked it. Please note that saying that a sexual act is done to please a partner does not make it non-consensual. It is not just that women accept being choked to please their partner; some men choke women only because they are asked to do it. More women than men found choking pleasurable, with 50.0% of undergraduate women and 26.8% of undergraduate men saying that it was very pleasurable. The number of graduate students that found it very pleasurable was 36.1% for women and 16.3% for men. Hence, a large majority of the students found breath play pleasurable. This can explain the growing popularity of choking, despite its reputation for being dangerous. However, this paper did not inquire into what made choking pleasurable. Consent Regarding consent, people who had been choked said that choking was consensual 92.1% of the time (Herbenick et al., 2022b). This number did not change much across genders or from undergraduates to graduate students. Among those who had been choked, choking was found to be consensual in all of their sexual encounters by 76.5% of women, 85.6% of men and 63.6% of non-binary people. In a more general survey about sex amongst college students (Herbenick et al., 2021), 21% of the students who had been choked said that they had never been asked for consent before being choked. An additional 32% of them said that they were asked for consent only sometimes. A qualitative survey (Herbenick et al., 2022a) found that the initial choking experience of many women occurred without discussing it beforehand or giving explicit consent. Often, consent was assumed or was sought while it happened. The authors remarked that consent to choking often fell in a gray area. For example, when verbal consent was given during sex or after sex. Sometimes consent was non-verbal, usually during sex. Other times, consent was assumed based on prior conversations, because they has done it before, the person’s interest in choking, or because it was assumed to be part of regular sex. Keep in mind that this happened among college students and not in the BDSM community, which has a strong consent culture. The students also considered choking to be safer than other forms of kinky sexy, an attitude that has been encouraged by the media (Herbenick et al., 2023). My survey in Fetlife I did my own inquiry into this by posting an article in Fetlife titled What Do You Like About Being Choked? It said: I heard some people say that being choked puts them in an altered state of consciousness that is different from sub space or from the effect of any drug. Is it true? In your experience, does choking make orgasms more intense? Or do you like choking for the psychological feeling that it brings you? Like, for example, surrender? Or perhaps you like the feeling of losing consciousness? Or is it a feeling of euphoria? Or is it something else? I think Fetlife was a good choice because I wanted to query specifically people who are into BDSM, and not those who practice choking as part of sex. However, the answers need to be interpreted in that context. I got 12 responses, 10 from women, 2 from non-binary persons and none from men. Four responders defined themselves as submissive, one as a slave, three as a masochist, one as a little, and the other three as exploring or curious. The following reasons were given to enjoy choking: Surrender (9 responders): loss of control, feeling helpless and vulnerable, feeling the power of the dominant, giving power to the dominant. Fear (5 responders), including feeling challenged and overcoming panic. Trust (4 responders): feeling that they could trust their safety to the choker. Euphoria (4 responders), including feeling high, lightheaded and physical pleasure. Orgasm and sensations are more intense (4 responders). Feeling safe, centered, calm (3 responders) despite the risk. Unconsciousness (3 responders). Edging to orgasm (2 responders). The most common responses align with the feelings usually sought in other BDSM activities: surrender to the power of the dominant, and the interplay between fear and feeling safe by trusting the top. But choking was also a source of pleasure. It produced euphoria and a high consisting of lightheadedness and physical pleasure. It also intensified physical sensations, including orgasm. Last, three people reported a paradoxical feeling of safety and calm, despite the obvious risk of the activity. My findings are consistent with one of the papers by the group of Debbie Herbenick (Herbenick et al., 2022a), a qualitative survey about the reasons why women like to be choked. In it, no participants reported actually losing consciousness. But many mentioned being excited about surrendering, empowering their partner, enhanced sexual arousal and longer orgasms. Fear and danger made the sex more exciting and pleasurable. Are the effects of choking similar to those of nitrous oxide? I was surprised not to find any mention to drug-like altered states of consciousness, which I heard about in some comments to my articles in Fetlife. When I asked if the feeling of being choked resembled the effect of any drug, one person responded that it did not feel like the effect of cannabis or psychedelics, but it could be similar to that of nitrous oxide, also known as laughing gas and whippets. Whippets are obtained as canisters to make whipped cream (Srichawla, 2022). They produce a severe deficiency in vitamin B12 (Maheshwari and Athiraman, 2022) and serious neurological effects. They are consumed because they produce euphoria, analgesia and a brief high. The mechanism of action of nitrous oxide is still unclear. It acts on many neurotransmitter receptors, blocking excitatory NMDA receptors and nicotinic acetylcholine receptors and potentiating inhibitory GABA and glycine receptors. Perhaps the brain hypoxia produced by choking has similar effects. Indeed, inhaling nitrous oxide as whippets produces hypoxia. References Herbenick D, Guerra-Reyes L, Patterson C, Rosenstock Gonzalez YR, Wagner C, Zounlome N (2022a) "It Was Scary, But Then It Was Kind of Exciting": Young Women's Experiences with Choking During Sex. Arch Sex Behav 51:1103-1123. Herbenick D, Patterson C, Khan S, Voorheis E, Sullivan A, Wright P, Keene S (2023) "Don't Just Randomly Grab Someone's Neck during Intercourse!" An Analysis of Internet Articles about Choking/Strangulation during Sex. J Sex Marital Ther 49:41-55. Herbenick D, Patterson C, Beckmeyer J, Gonzalez YRR, Luetke M, Guerra-Reyes L, Eastman-Mueller H, Valdivia DS, Rosenberg M (2021) Diverse Sexual Behaviors in Undergraduate Students: Findings From a Campus Probability Survey. The journal of sexual medicine 18:1024-1041. Herbenick D, Fu TC, Eastman-Mueller H, Thomas S, Svetina Valdivia D, Rosenberg M, Guerra-Reyes L, Wright PJ, Kawata K, Feiner JR (2022b) Frequency, Method, Intensity, and Health Sequelae of Sexual Choking Among U.S. Undergraduate and Graduate Students. Arch Sex Behav. Maheshwari M, Athiraman H (2022) Whippets Causing Vitamin B12 Deficiency. Cureus 14:e23148. Srichawla BS (2022) Nitrous Oxide/Whippits-Induced Thoracic Spinal Cord Myelopathy and Cognitive Decline With Normal Serum Vitamin B₁₂. Cureus 14:e24581. Copyright 2023 Hermes Solenzol.

The two main practices to induce asphyxia for pleasure I strongly recommend not to practice choking. This article is part of a series intended to show that choking is unsafe, may cause brain damage, and is potentially lethal. Choking, as it is used during sex or in BDSM, aims to deprive the brain of oxygen to induce mental changes that are pleasurable, either by themselves or because they intensify sexual sensations. This can be done in two ways: by interrupting the air flow into the lungs (“air choke”) or by interrupting the blood supply to the brain (“blood choke”). This terminology comes from martial arts. There is some debate in the BDSM community about which one is better. The air choke Still, most of the choking during sex is done by squeezing the throat with one hand (Herbenick et al., 2022). It is hard to say if this is an air choke or a blood choke. If pressure is applied to the front of the neck, this can close the trachea, producing an air choke. However, applying pressure to the trachea is unpleasant and dangerous, because it can damage the vocal cords, impairing speech. It can also damage the thyroid gland or the trachea itself, which can have serious health effects. The trachea is a very delicate structure made of cartilage, a tissue similar to bone that also makes our joints. This makes the trachea semi-rigid, so applying pressure on it can deform it permanently. Therefore, this form of choking can produce long-term damage affecting breathing, talking and swallowing. A crushed trachea is life-threatening. You can kill somebody this way. Another straightforward way to produce an air choke is to block the nose and the mouth with the hand. A person can easily get out of this choke by struggling, which can be both a problem - involuntary struggling can stop the choke - and an advantage - a built-in safety feature. Deep throating - inserting the penis into the mouth deep enough to block air passage into the larynx - can be a form of choking. However, the gagging reflex would be induced much sooner than air deprivation is felt. Besides, a panicking bottom can bite the cock that is gagging him or her. Using a pillow or a mask to block breathing is dangerous because the top cannot see the face of the bottom, and therefore cannot judge the level of asphyxiation. This could be prevented by using a transparent bag, but removing it takes too long. Still too dangerous. Some people use a sharp object to quickly puncture the bag, but this risks cutting the face of the person being choked. The blood choke (carotid occlusion) The blood choke consists of stopping the blood supply to the brain by blocking the carotid arteries. They run superficially on both sides of the neck and can be blocked by applying a small amount of pressure on the right spots. On purpose or by accident, this is probably what it is done in some of the one-hand chokes that are more prevalent, according to the surveys. A common chokehold in martial arts consists in wrapping the neck of the adversary with one arm from behind, in a position resembling the number 4. This compresses the carotid arteries and jugular veins, but not the trachea, cutting the blood flow to the brain and thus inducing unconsciousness in 10-20 seconds. However, using this chokehold during sex of BDSM play has the problem that the person applying the choke cannot see the face of the person being choked, and therefore cannot regulate the pressure and the timing to avoid going too far. Unlike in martial arts and self-defense, most people that use choking during sex do not want to induce unconsciousness. Neither should they, since loss of consciousness by anoxia often leads to brain damage. Hence, the most common way to induce a blood choke during sex is to apply pressure to the sides of the neck with one hand, while looking into the face of the person being choked to evaluate their response. Which one is safer? Some people in the BDSM community argue that the blood choke is safer than the air choke for the following reasons: It affects only the brain and not the rest of the body. The blood flow can be manipulated quickly and subtly by changing the pressure of the hand. Changes in consciousness can be induced and restore quickly. It avoids damaging the trachea and other delicate structures in the neck. It does not increase the CO2 levels of the blood and hence blood acidity, like the air choke does. However, the blood choke has dangers that are not obvious at first sight. But understanding these dangers requires some complicated explanations about the functioning of the brain and cardiovascular physiology, which I will give in the next articles. For now, let me just say that the blood choke is, in fact, more dangerous than the air choke. Previous articles in this series https://www.hermessolenzol.com/en/post/how-common-is-sexual-choking https://www.hermessolenzol.com/en/post/why-do-people-enjoy-being-choked https://www.hermessolenzol.com/en/post/how-deathly-is-choking

Choking is the main cause of death in BDSM, but less common than it is thought I strongly recommend not to practice choking. This article is part of a series intended to show that choking is unsafe, may cause brain damage, and is potentially lethal. Deaths by autoerotic asphyxiation Choking appears in the popular imagination as a deathly activity, largely because of the many celebrities that have died of autoerotic asphyxiation. However, it is important to distinguish between breath play practiced in solitary and that practiced in couples. In the former, loss of consciousness or control over the body can lead to dead because the person cannot escape the asphyxia, while in the latter the person doing the choking has some control over the process. But even the number of deaths produced by autoerotic (i.e. solitary) asphyxiation has been exaggerated. It is often mentioned that it causes “500 to 1000 deaths per year in the United States and Canada” (Sauvageau, 2012), but that number is an estimation based on unpublished data. An epidemiological study based on 38 autoerotic deaths in Alberta, Canada, gave a lower number: 0.56 deaths per million inhabitants per year (Sauvageau, 2012). Multiplying this number by the population of the United States, 333 million, gives us an estimate of 186 deaths per year caused by autoerotic asphyxiation. The number of autoerotic deaths per million inhabitants per year is similar in other developed countries: 0.3 in Australia, 0.14 in Sweden and 0.5 in Germany. Choking deaths in BDSM Another paper (Schori et al., 2022) inquired specifically about deaths involved in BDSM play. Doing a literature search, they identified 17 deaths produced by BDSM activities. Of those, all were caused by asphyxia except one case, in which death was caused by hemorrhage due to inserting an inflatable balloon and other objects in the vagina. One death by asphyxia was caused by blocking the mouth and the nose with tape and fingers. The remaining 15 deaths were by strangulation, 5 with the hand or the forearm and 10 with ligatures (rope, belt, collar or chain). One of the cases of strangulation was a shibari scene in which two women were hanged with the same rope suspended from the ceiling (Roma et al., 2013). When one of them lost consciousness, her weight hanged the other. The first ended up death and the second, in a coma. The rate of death was similar across genders: 9 men and 8 women. In 9 of the cases, both partners were experienced in BDSM. In 2 cases, the top was a professional dominatrix. In 3 cases, the participants had discussed breath play techniques and cardiopulmonary resuscitation (CPR). Therefore, experience and education were not enough to prevent the deaths. Conclusions The conclusions are a mixed bag. On the one hand, fatalities caused by BDSM are rare: 15 occurred in the United States from 1986 to 2020, and 3 in Germany from 1993 to 2017. On the other hand, breath play caused a disproportionate number of the deaths in BDSM. It is fair to say that, by far, choking is the most deathly BDSM activity. But dying is only the worst thing that can happen during breath play. There may be other health consequences, including brain damage. These are much harder to assess. I will discuss that in future articles. References Roma P, Pazzelli F, Pompili M, Girardi P, Ferracuti S (2013) Shibari: double hanging during consensual sexual asphyxia. Arch Sex Behav 42:895-900. Sauvageau A (2012) Autoerotic deaths: a 25-year retrospective epidemiological study. Am J Forensic Med Pathol 33:143-146. Schori A, Jackowski C, Schön CA (2022) How safe is BDSM? A literature review on fatal outcome in BDSM play. International Journal of Legal Medicine 136:287-295. Copyright 2023 Hermes Solenzol.

Dying is not the only danger of choking I strongly recommend not to practice choking. This article is part of a series intended to show that choking is unsafe, may cause brain damage, and is potentially lethal. What happens when the brain lacks oxygen? To stay conscious and alive, our brain needs a continuous supply of oxygen and glucose from the blood. Neurons are the most finicky cells of the body. If they don’t get their oxygen, they throw a tantrum and die. Tantrum is quite an appropriate metaphor, because a neuron that is starving for oxygen begins firing a lot of action potentials and releasing its neurotransmitters. The main excitatory neurotransmitter in the brain is the amino acid glutamate, which is also an abundant metabolite. When a neuron dies, all of its glutamate is released into its surrounding medium, activating glutamate receptors in its nearby neurons. Too much activation of glutamate receptors kills those neurons, too, setting off a chain reaction that produces a wave of cell death spreading through the brain. This glutamate release is what produces brain damage during a stroke. A stroke happens when a capillary inside the brain is blocked by a blood clot. Neurons that were supplied with oxygen by that capillary die, releasing glutamate and starting this wave of death. So, why doesn’t it end up killing the whole brain? Because there are cells in the brain, the glia, that are in charge of preventing damage by absorbing glutamate and other neurotoxic substances. Still, considerable harm can be done before these cells manage to bring the situation under control. Once neurons die, the body cannot replace them. The carotid arteries detect blood pressure Oxygenated blood is supplied to the brain through the carotid arteries, situated on the sides of the neck, towards the front. Just above the thyroid cartilage, or Adam’s apple, the carotid arteries split into the external carotid, which supplies blood to the face, and the internal carotid, which supplies blood to the brain. This bifurcation of the carotid artery is very important because it forms the carotid sinus, a swelling of the internal carotid artery. The carotid sinus is one of the two places in the circulatory system where there are baroreceptors. The other place is the aortic arch, situated in the aorta artery just above the heart. Baroreceptors are sensory neurons is charge of detecting blood pressure. They send this information to the brain so it can adjust the beating of the heart and the dilation of the capillaries. The carotid sinus sends blood pressure information to the brain through the glossopharyngeal nerve, while the aortic arch sends it through the vagus nerve. Both nerves end in the same place: the nucleus of the solitary tract or solitary nucleus, in the medulla oblongata. The solitary nucleus modulates the activity of the sympathetic and parasympathetic systems through the hypothalamus. Among other things, this modulates the heartbeat and the dilation of the capillaries, forming a feedback loop that controls blood pressure. Problems with the blood choke In a previous article, I explained that an air choke is blocking the entrance of air into the lungs, while a blood choke is blocking the carotid arteries and the jugular veins to interrupt the blood supply of the brain. The information above is crucial to understand the problems with the blood choke. In an air choke, a person can survive for several minutes without breathing. The air that remains in the lungs and the oxygen stored in the blood's hemoglobin and the muscles’ myoglobin can supply the organs, including the brain, for some time. Free-divers can hold their breath and remain conscious for several minutes, even while swimming vigorously in cold water (Scott et al., 2021). Interrupting the oxygen supply to the brain is an entirely different matter. Unconsciousness takes place in 10 to 20 seconds, irreversible neurological damage before one minute, and death soon afterwards. Therefore, a blood choke has to be timed precisely to avoid brain damage and death. But even if a blood choke is done for a time short enough for survival, there are other problems involved. It compresses or blocks the carotid arteries, which supply blood to the brain, and the jugular veins, which are the exit route of blood from the brain. This decreases blood flow (cerebral ischemia) and therefore the supply of glucose and oxygen (cerebral hypoxia). This represents a big problem for the brain, as shown by the damage caused by stroke. Except that, with a blood choke, we are altering the blood supply to the entire brain and not just a small part of it. Some neurons may be more sensitive to hypoxia than others, resulting in localized trauma that is hard to detect. Reperfusion injury Another problem is reperfusion injury, the harm produced when blood suddenly enters a tissue that has been deprived of it. Reperfusion increases the production of reactive oxygen molecules from the sudden increase in oxygen, as well as cytokines and chemokines, which are pro-inflammatory molecules produced by immune cells and microglia (Kalogeris et al., 2012). All this is extremely damaging to nervous tissue. The vasovagal response Yet another problem arises from the fact that the carotid sinus contains the baroreceptors that control blood pressure in the entire body. A blood choke changes the pressure detected by these baroreceptors. Pressure on the neck above the trachea would be exerted directly on the carotid sinuses, stimulating the baroreceptors. Pressure lower on the neck would decrease the blood reaching the carotid sinus, making it detect a lower blood pressure. The error signal thus produced in the carotid sinus would affect the beating of the heart, usually decreasing it. A highly controversial issue among pathologists is whether this could stop the heart altogether. This could explain why some deaths by strangulation occurred even though the choke did not last long enough to produce brain damage. The vasovagal response or reflex syncope “is a brief loss of consciousness due to a neurologically induced drop in blood pressure. Before the person passes out there may be sweating, a decreased ability to see, or ringing in the ears. […] Carotid sinus syncope is due to pressure on the carotid sinus in the neck. The underlying mechanism involves the nervous system slowing the heart rate and dilating blood vessels resulting in low blood pressure and therefore not enough blood flow to the brain.” Wikipedia. Other problems with the blood choke Messing with the blood pressure sensing by the baroreceptors in the carotid sinuses also affects the sympathetic and parasympathetic nervous systems, explaining why choking can produce reactions like nausea and vomiting. The whole body is thrown out of balance. There may be other complications of carotid occlusion, like cholesterol plaques being released from inside the carotids to cause strokes in the brain. Carotid occlusion is much more dangerous than other forms of asphyxiation. The key fact is that when you hold your breath, or when somebody blocks your breathing, there is a big reservoir of oxygen that your body can use to stay alive. However, your brain cannot store oxygen. When you block the carotids, your brain starts to run out of oxygen right away. Is there a risk of cumulative brain damage? Even if it does not cause death, repeated choking to the point of unconsciousness may have cumulative effects, leading to brain damage. Neuronal death may happen without any symptoms because the brain is very good at compensating for loss of function. You don’t know what is going on in your brain when you drive it close to unconsciousness, just because it’s so much fun! Your neurons could be dying while you party. This is what happened with traumatic brain injury (TBI), which is now called a “silent epidemic” (Alkhaibary et al., 2021). Sports like boxing and football cause repeated concussions that have an additive effect. When TBI finally manifests itself, it is too late to do anything about it. TBI is different from one person to another because different brain regions are affected. It produces sensory hypersensitivity, chronic pain, motor problems, memory loss and cognitive decline. While TBI and brain anoxia may seem different, they both involve neuronal death, so they may produce similar symptoms. Recreational choking may lead to another silent epidemic that would remain unknown for many years because the symptoms take a long time to appear and their cause may not be apparent at first. But, is there any evidence of this? Or is it just speculation and fearmongering? In the next article of this series, I will present evidence that repetitive choking leads to cognitive deficits and psychological problems. References Alkhaibary A, Alshalawi A, Althaqafi RMM, Alghuraybi AA, Basalamah A, Shammaa AM, Altalhy AA, Abdelrahman TM (2021) Traumatic Brain Injury: A Perspective on the Silent Epidemic. Cureus 13:e15318. Kalogeris T, Baines CP, Krenz M, Korthuis RJ (2012) Cell biology of ischemia/reperfusion injury. Int Rev Cell Mol Biol 298:229-317. Scott T, van Waart H, Vrijdag XCE, Mullins D, Mesley P, Mitchell SJ (2021) Arterial blood gas measurements during deep open-water breath-hold dives. J Appl Physiol (1985) 130:1490-1495. Copyright 2023 Hermes Solenzol.

Scientific studies show that women who are choked have more psychological problems and changes in brain connectivity I strongly recommend not to practice choking. This article is part of a series intended to show that choking is unsafe, may cause brain damage, and is potentially lethal. Health problems in women who have been choked during sex Even serious brain injury can go undetected because the brain is very good at hiding it. Hence, there have been studies aiming to determine if women who had been choked showed signs of brain injury. Women who had been choked during sex more than five times in the last month were more likely to feel sad, lonely, anxious and depressed than women who had never been choked (Herbenick et al., 2022). “Women with a history of being choked more than five times during sex within the past 30 days were 2.19 times as likely to endorse experiencing overwhelming anxiety, 2.16 times more likely to report feeling very sad, 1.59 times more likely to report being very lonely, and 1.77 times more likely to feel ‘so depressed that it was difficult to function’ than women who had never been choked.” (Huibregtse et al., 2022). Women who had been choked during intimate partner violence There are also detailed studies of psychological and cognitive problems in women who had been choked during intimate partner violence. One of them (Valera et al., 2022) found that these women showed deficits in long-term memory, had higher levels of depression and presented symptoms of posttraumatic stress. However, some of these problems may derive from the psychological trauma produced by the assault and not from the strangulation itself. A review of 30 papers about strangulation during domestic and sexual violence (Bichard et al., 2022) showed that the victims presented the following problems: Pathological: tears in the arterial wall and stroke. Neurological: loss of consciousness, seizures, motor and speech disorders and paralysis. Psychological: posttraumatic stress, depression, suicidal ideation and dissociation. Cognitive: memory loss. Behavioral: aggression, compliance with the aggressor and lack of help-seeking. Obviously, strangulation during violence is much more severe than that occurring during consensual sex and BDSM. Still, its consequences show what can happen if choking is taken too far. In particular, loss of consciousness should be considered a sign that choking is extreme enough to produce brain injury. Brain imaging studies in women who had been choked during sex But, is there evidence that choking during sex produces brain damage? I found two studies that did this using brain imaging (fMRI) and tests of brain function. One study (Hou et al., 2022) compared 21 women who had never been choked with 20 women who had been choked four times or more during the last month, using fMRI to measure the functioning of the cortex and brain connectivity. The paper reports that women who had been choked showed an imbalance in neural activation between the brain hemispheres. They also showed higher than normal connectivity between the angular gyrus and brain regions involved in motor control, emotion and consciousness. The angular gyrus is involved in comprehension while reading, number processing, spatial cognition, memory retrieval and attention. It is hard to tell what these increases in connectivity mean, or even if they are caused by the choking. Another study (Huibregtse et al., 2022) used a similar sample: 20 women who had been choked at least four times during the last month and 20 women who had never been choked. Their brains were imaged using fMRI while they did verbal and visual tasks to measure their working memory. Both groups of women performed equally well in these tasks. However, the fMRI revealed that, during the verbal memory task, women in the choked group showing increased activation of their corpus callosum, left posterior thalamic radiation, left caudate nucleus and left insula. The corpus callosum is the bundle of fivers that connect the brain hemispheres. The thalamus is the sensory relay in the middle of the brain. The caudate nucleus is part of the striatum and reward system, and is involved in motor control and learning. The insula processes the emotions associated with pain and pleasure, and other emotions. During the visual memory task, women in the choked group showed more activation of the superior and right middle frontal gyri. As the difficulty of the task increased, the choked group showed less activation of the middle and the right inferior frontal gyri. The frontal gyri are involved in involved in self-awareness, decision-making and impulse control. They are also critical for working memory. The authors of the study concluded that, although the women who had been choked did not show a decreased ability in the working memory tasks, they had to allocate increased resources to the parts of their brain involved in performing these tasks. This could indicate hypoxic or ischemic damage or reperfusion injury produced by the repeated choking. Or there could be a remodeling of brain networks. These two studies show that there are definite differences between the brains of choked women and women who had never been choked. These differences appear minor, but they could signal a build-up of brain trauma. Keep in mind that the women in these studies were young college students. Older brains might show more problems after choking. Is choking worth the risks? I don’t think choking for fun is worth the risks. There many other ways to have fun with sex and BDSM that are much safer. I consider choking unsafe and I advise against doing it. If you put together everything I wrote in this series of articles, you will realize that there are no safe ways to practice choking safely. The analyses of cases of death from choking show that there is a low but significant risk of death that cannot be mitigated by any amount of knowledge and safety precautions. Recoveries from cardiac arrest are much rarer than what movies make us think they are. Even if nobody dies, repetitive choking can induce cumulative brain damage. Especially if choking induces loss of consciousness. This article presents evidence that cognitive and psychological deficits occur in people who are frequently choked. Some people may just like to put a hand on the throat and do some pretend choking. As long as there is no blockade of blood flow to the brain or air entry to the lungs, this is fine. But you should not call it choking, because that normalizes choking for other people. The safety of choking is still hotly debated in the BDSM community. However, most BDSM organizations and clubs do not allow choking in their facilities. Sex adviser Dan Savage advises against it in The Savage Lovecast, where he has interviewed professor Debbie Herbenick, the author of many of the papers I have cited here. In the end, whether to choke or not is a risk that should be assumed by the individuals involved, with full consent and plenty of information. However, as we have seen, both things are often lacking when it comes to choking. To be fully informed on this matter requires some in-depth knowledge of physiology and neuroscience. Weighing pleasure, on the one hand, against a real possibility of brain damage and death, on the other, the decision seems quite obvious to me. But I also think it’s important that we continue having a conversation about this issue. If people are going to do it, we need to continue to evaluate its risks and disseminate information about the safest way to do it. References Bichard H, Byrne C, Saville CWN, Coetzer R (2022) The neuropsychological outcomes of non-fatal strangulation in domestic and sexual violence: A systematic review. Neuropsychol Rehabil 32:1164-1192. Herbenick D, Fu TC, Kawata K, Eastman-Mueller H, Guerra-Reyes L, Rosenberg M, Valdivia DS (2022) Non-Fatal Strangulation/Choking During Sex and Its Associations with Mental Health: Findings from an Undergraduate Probability Survey. J Sex Marital Ther 48:238-250. Hou J, Huibregtse ME, Alexander IL, Klemsz LM, Fu TC, Fortenberry JD, Herbenick D, Kawata K (2022) Association of frequent sexual choking/strangulation with neurophysiological responses: a pilot resting-state fMRI study. J Neurotrauma 40:1339-1351. Huibregtse ME, Alexander IL, Klemsz LM, Fu TC, Fortenberry JD, Herbenick D, Kawata K (2022) Frequent and Recent Non-fatal Strangulation/Choking During Sex and Its Association With fMRI Activation During Working Memory Tasks. Frontiers in behavioral neuroscience 16:881678. Valera EM, Daugherty JC, Scott OC, Berenbaum H (2022) Strangulation as an Acquired Brain Injury in Intimate-Partner Violence and Its Relationship to Cognitive and Psychological Functioning: A Preliminary Study. J Head Trauma Rehabil 37:15-23. Copyright 2023 Hermes Solenzol.

When I look at the amazing description of the Universe created by science, I find that it is all full of meaning I would define “meaning” as something larger than ourselves that gives a sense of purpose and direction to our lives. Having meaning in life is one of the key ingredients of happiness, because for most people a life worth living needs to have purpose in a larger context. Meaning and ethics Meaning is also important as a foundation for ethics. Systems of values can be reduced to a few fundamental premises from which codes of ethics can be developed rationally. However, those premises themselves are arbitrary unless they can be referred to some other knowledge, like an understanding of what it means to be human, or a description of the world. For example, Christianity and Islam base their ethics on the will of God. This is based on the belief that God created the Universe and His will takes priority over anything else. However, this system of ethics falls apart when we question the belief in God, or the morality of submitting to the will of a God that allows suffering. In Utilitarianism, ethics are based on maximizing happiness and minimizing suffering. This is based on the belief that being happy and avoiding suffering is the ultimate objective of our lives. Similarly, Buddhism makes its ultimate goal the overcoming of suffering by understanding our innermost nature. However, being happy and overcoming suffering look like rather short-sighted goals. We are left wondering: isn’t there anything more to life? Nihilism The belief that life is devoid of meaning is called nihilism. According to this view, being happy and avoiding suffering are spurious goals that are themselves devoid of meaning. Therefore, establishing any foundation for ethics on them is also futile. Many people reject nihilism because it leads to a cynical outlook on life in which nothing that we do ultimately makes sense. It leads to its own kind of suffering: the existential angst of believing that our life has no purpose. A humorous example of the nihilistic and cynical outlook that some people derive from science can be found in The Universe Song, by Monty Python, featured in their movie The Meaning of Life. Existentialism Existentialism says that the only place we can find meaning is in our own lives and in human enterprises. That is, meaning is to be found inside, not outside ourselves. Today this is has become the common belief of most people who reject religion and adopt a value system based on science and rationality. Our cooperative nature, empathy and sense of solidarity make it meaningful for us to strive to improve the lot of our fellow humans. In politics, socialism makes the attaining of an egalitarian and free society a goal that provides meaning to our lives. Indeed, a utopian society is a goal larger than ourselves, so it can provide purpose and direction to our lives. Problems with existentialism However, there are some problems with defining all ethics exclusively on the basis of human happiness and suffering. Take environmentalism, for example. It can be argued that a good environment is good for humans, so we should strive to improve it. Nevertheless, humans could be perfectly happy if an obscure species of insect or plant goes extinct. And yet our intuition tells us that extinguishing species is wrong and should be avoided, even at a relatively high cost. Environmental laws in the USA and most developed countries are based on that principle. Another example is science. It is common to argue that scientific research is valuable because it will bring cures for diseases and new devices that would make us happier. But if this was true, then we should stop expending enormous amounts of money sending probes to explore the Solar System and beyond, or doing research on particle physics, because those enterprises don’t do much to cure our suffering or to make us happy. Every scientist secretly knows that we do science primarily for the sake of knowledge itself, not for its application. In fact, scientific knowledge often brings good and bad things: nuclear power and atomic bombs; pharmaceuticals and environmental poisons; the internet and its ability to control our minds; gene therapy and genetic manipulation. For every blessing there is a curse. No wonder that some people feel that we should retreat to a simple, agrarian society without science and technology, or even to being the hunter-gatherers that we were before the Agrarian Revolution. Some even think the world would be better off without any humans at all. What I am going to argue here is that meaning can be found not just inside us, but also outside in the Universe. Furthermore, this idea is based on scientific knowledge and not on religious belief. The evolution of everything If we take a step back and look at what science has shown, we see that the Universe is not a series of random processes. It has been evolving since the Big Bang in a definite direction: an increase in complexity and organization. And this can even be formalized scientifically: the amount of information that we need to describe the Universe has increased over time. In the beginning, there were just basic particles: photons, electrons, protons, neutrinos, etc. When the Universe cooled enough, electrons and protons got organized into hydrogen atoms. Stars got formed by gravity, and hydrogen turned into helium inside them. Then, as the star aged, hydrogen turned into carbon and the other light atoms of the Periodic Table. Stars exploded into novas and supernovas and collapsed into neutron stars, given birth to the heavier atoms. This stardust floating in space forming nebulae eventually gives to new stars, which now had planets where this new zoo of atoms is collected. On Earth, carbon, hydrogen, nitrogen, oxygen and a few other atoms organized themselves into living beings. Evolution started, creating more and more life forms. While it is true that evolution does not proceed in any particular direction, it is also true that the algorithm of genetic mutation plus natural selection acts to fill every ecological niche by creating beings of every possible size and shape (Stuart Kaufman, At Home in the Universe). This generates simple life forms, but also large, complex animals. One of them is the human being. Human’s ace-in-the-hole to win the natural selection game is having a large brain that allows cooperative behavior based on the transfer of information, not only in the present by also across time, from generation to generation. Just like life once appeared, culture shows up as something entirely new. One form of culture is science, with all its wonderful tools to extract and organize information about everything. We become the eyes by which the Universe sees itself. Among other things, we now know that the Sun is not unique in having planets capable of evolving life. Hence, the same process of evolution: random search for new forms and the eventual appearance of intelligence could have happened elsewhere. Everywhere! Billions of stars playing at the roulette of life and intelligence. How many winners? Probably a lot. The hierarchy of being When we look at this whole process we realize that it is organized in the form of a nested hierarchy. By that, I mean that there are several discrete levels of complexity, each one built upon the lower one: physics, chemistry, biology, neuroscience, psychology, sociology. We have a different science to study each level. This is not by caprice, but because each level has its own rules that have to be studied separately and cannot be deduced from the rules of the lower level (Ray Kurzweil, The Singularity Is Near: When Humans Transcend Biology). This is called emergence: the fact that new laws appear at a certain point in time, which coexist with the laws of the lower level but constitute entirely new phenomena. Thus, the laws of chemistry add novelty to the laws of particle physics. And when life appears, it follows laws that are quite different from the laws of chemistry. And on and on to the laws that govern nervous systems and those that rule human interactions. What causes emergence? In one view, evolution and other processes that create complexity and self-organization are algorithms: information processing events that follow certain rules of computation to generate an outcome from original conditions (Charles Seife, Decoding the Universe; Seth Lloyd, Programming the Universe). For example, the algorithm of evolution is: generate mutations in the DNA; output them in the phenotype; test phenotype against the environment; IF death, discard the mutation; IF survival, amplify the mutation by reproducing; Go to step 1 while producing offspring. This algorithm explores a landscape of all possible shapes of living beings, while natural selection eliminates shapes that are not fit for the environment (Stuart Kaufman, At Home in the Universe, Investigations). In fact, the algorithm is itself the product of early evolution and natural selection. Mutation is not random, as previously suspected, but perfected by natural selection so that some parts to the DNA are more susceptible for mutation than others and there are specific mechanisms to generate genetic variation (Lynn Helena Caporale, Darwin in the Genome). A meaningful Universe? What does all this have to do with finding meaning in our lives? Well, we intuitively value the complexity and self-organization that we see in living beings. We have the same admiration for intelligence and culture, which we see as one step above mere life. The fact that the Universe has steadily moved to create life and then ourselves indicates that we are part of a process much larger than ourselves, something truly awe-inspiring. So it is not just that we are working for the good of Humanity while Humanity in itself has no meaning. Humanity does have meaning because it is part of a larger process encompassing the whole history of the Universe. Will this process continue in the future, beyond Humanity? Here it is tempting to fall into the heresy of teleology, which is saying that evolution has a particular goal, like producing human beings, or that the Universe has a goal, like producing consciousness or intelligence. This idea has been condemned because goals are something that humans have, not inanimate matter. However, as I argue in another article, agency (doing something to achieve a particular outcome) could be considered a property of living beings. And, looking at the past, it is unavoidable to conclude that the Universe has evolved in the direction of increasing complexity and self-organization and that this has led to the appearance of information-rich organisms and intelligence. Transhumanism Indeed, what we are doing right now is creating computers that store all our cultural information and also generate information in increasingly larger amounts. Is that the next step of the universal evolution? Are we going to continue to be part of the process, or will we be left behind? Transhumanism is a modern philosophy that, based on this view of the Cosmos, proposes that we can find meaning in the future development of the human race. It hopes that we will walk hand-in-hand with computers instead of being replaced by them (Ray Kurzweil, The Singularity Is Near: When Humans Transcend Biology). We may be able to do that by linking our brains directly to a computer, perhaps eventually migrating our entire consciousness into a computer. Conclusions It is not that the Universe has meaning in itself. Is that we are able to find meaning when we contemplate how the Universe has been evolving to give rise to consciousness, intelligence and culture. We humans are the ones who can assign value and beauty to things outside ourselves. We look at a crashing wave, at a snow-crested mountain, at a dolphin, and find those things beautiful. Likewise, we consider how stars smash atoms together, how planets are created from clouds of interstellar gas, how life arises and evolves, how consciousness emerges from complex nervous systems, and we are filled with awe. We do not exist independently of the Cosmos, we are stardust that has gained consciousness. What we do in our lives, the destiny of Humanity, matters because it is part of this amazing cosmic play. We do not know where the Universe will go from here, but somehow we suspect it will very much be worth the ride.

Different patterns of dopamine release in the reward pathway mediate motivation and addiction The dopamine myths There is much confusion these days about what dopamine does in the brain. The logic goes like this: Drugs produce addiction by releasing dopamine in the brain. Pleasurable activities release dopamine in the same brain region. Therefore, pleasurable activities must also produce addiction. Yes, the logic is not entirely sound. The devil, as always, is in the details. After all, dopamine is constantly being released inside the brain. When you block dopamine release in mice, they lack motivation for doing anything and die of thirst and starvation (Wise and Jordan, 2021). Some people even take it a step further (Lembke, 2021). They reason that too much pleasure must deplete the brain of dopamine, leading to an unhealthy state of lack of motivation. Therefore, we must try to conserve dopamine by avoiding too much pleasure. Especially masturbating or watching porn. These ideas are everywhere nowadays. They are key to the NoFab anti-masturbation movement. Its ideas have been absorbed by the manosphere, which seeks to make men more manly, powerful and less dependent on sex. But they are also supported by radical feminists, who have been campaigning against porn since the 70s. And, of course, religious conservatives are always happy to find arguments against porn, masturbation, sex and anything pleasurable. Here are a few examples of these dopamine beliefs: Porn and masturbation are addictive. Video games are addictive. Social media, and smartphones in general, are addictive. You can become addicted to loving a person. Too much pleasure depletes the brain of dopamine, leading to a state of pain, lack of motivation and weak willpower. Dopamine fasting - avoiding the addictive drug or behavior for 30 days - can be used to stop an addiction. Are behaviors addictive? These beliefs are defended in the book Dopamine Nation, by Anna Lembke, M.D (see critical reviews here). It makes three main claims: That behaviors like masturbation, watching porn, reading romance novels, gaming, social media, and using your cell phone, are as addictive as drugs like cocaine and heroin; That pleasure and pain need to be maintained in balance - if you experience too much pleasure, you will pay with pain; That drugs and behaviors like those listed above require a 30-day dopamine fast to get out of addiction. These beliefs about dopamine are also featured in some episodes of the podcast of Andrew Huberman, particularly the one of August 16, 2021, where he interviews Dr. Lembke, and the one of March 27, 2023, “Leverage Dopamine to Overcome Procrastination & Optimize Effort.” I generally like the Huberman Podcast. It provides good information about neuroscience and good life advice. However, sometimes (as in the case of dopamine) it lacks enough scientific rigor and critical thinking. The book The Compass of Pleasure, by Dr. David Linden, also defends the idea that we can become addicted to sex and love. However, it does so as an afterthought. Its main goal is to explain the involvement of the dopamine reward pathway in pleasure. It is worrisome that these prestigious neuroscientists defend the idea that behaviors can be addictive. This article focuses on examining this issue by diving into the details of dopamine release in the reward pathway of the brain. To keep it short, I will leave other claims related to dopamine for another occasion. This is a contentious issue with important social and political ramifications. If left unchallenged, this trend of demonizing sex and pleasure as addictive can start a new era of puritanism and repression. Hence, it is important to treat it with the necessary scientific rigor. Besides having a 40-year research career on the neuroscience of pain and opioids, I have researched this issue extensively to find peer-reviewed articles to support what I say. The reward pathway In 1953, James Olds and Peter Milner were postdoctoral fellows at McGill University in Montreal. By being a bit clumsy, they made a discovery of great consequence (Olds and Milner, 1954; Olds, 1958; Linden, 2012). They worked in the lab of neuropsychologist Donald Hebb, famous for hypothesizing the mechanisms of memory by saying “neurons that fire together, wire together.” Olds and Milner were investigating the reticular system, an area in the midbrain that control sleeping and waking. But the electrodes they implanted in one particular rat were a bit off and landed in the septum instead of the reticular formation. When the rat recovered from surgery, they placed it in a large rectangular box. Every time that the rat was in a particular corner, Olds stimulated its brain by passing current through the electrode. The rat soon learned to return to that corner. Apparently, it liked its brain being stimulated in the septum. In this, it behaved differently than rats that had electrodes placed in the reticular system. Olds and Milner soon learned just how much rats enjoyed having their brains stimulated in the septum. They used a set-up called a Skinner box, in which rats could press a lever to deliver the electrical stimulus to their brain. When implanted with electrodes in this brain region, the rats would press the lever several thousand times per hour. Given the choice between water or food, on the one hand, or pressing the lever, on the other hand, the rats always chose to press the lever. Male rats would rather press the lever than mate with female rats in heat. Female rats abandoned their pups to go and press the lever. It was tempting to call this neuronal path the pleasure pathway. They called it the reward pathway, instead, or by the more technical name of mesolimbic pathway. By systematically placing electrodes in different parts of the brain of rats, scientists mapped this reward pathway. It runs in the middle of the bottom of the brain, back to front, from the ventral tegmental area (VTA) to the nucleus accumbens. It also sends dopamine-containing axons to the prefrontal cortex, the anterior cingulate cortex, the thalamus and the hypothalamus. The VTA, together with the substantia nigra, contains many of the dopamine neurons of the brain. VTA neurons also send dopamine-releasing (dopaminergic) axons to the prefrontal cortex (volition), the anterior cingulate cortex (decision-making and planning), the amygdala (involved in fear and anxiety) and the hypothalamus (control of body functions). This is important, because dopamine maintains the function of these areas of the brain over long periods of time. For example, effects of dopamine on the anterior cingulate cortex and the prefrontal cortex are essential for flow (Kotler et al., 2022), a mental state of effortless effort, focused attention and creativity. What does it feel like to have your reward pathway stimulated? Inevitably, electrodes were placed in the reward pathway of humans to see what they felt when it was stimulated. Just like the rats, when humans were given the opportunity to stimulate the own reward pathway by pressing a lever, they did so non-stop. But what did they feel? In his book The Compass of Pleasure, neuroscientist David Linden says that they experienced euphoria, a state of well-being and excitation, but he doesn’t give any references to support this. Is the reward pathway really a pleasure pathway? Let’s start with orgasm. Indeed, the VTA and the nucleus accumbens are activated during orgasm (Wise et al., 2017). However, several other brain regions are also activated during orgasm: the insula, operculum, anterior cingulate cortex, orbitofrontal cortex, right angular gyrus, paracentral lobule, cerebellum, hippocampus, amygdala, hypothalamus and dorsal raphe. In particular, the insula and its nearby operculum mediate the emotions associated with body sensations, so they may be key for the pleasure produced by the orgasm. The anterior cingulate and prefrontal cortex may mediate the desire to continue sexual stimulation. The hypothalamus mediates the release of oxytocin that produces bonding during sex. What about other kinds of pleasure? The linking reaction to sweets is mediated by a “hedonic hotspot” in the shell of the nucleus accumbens (Mitchell et al., 2018). The pleasure produced by music is associated with dopamine release in the striatum, which includes the nucleus accumbens (Salimpoor et al., 2011). This study used positron emission tomography (PET) to get images of the brain as dopamine displaces [11C]raclopride from dopamine receptors. Dopamine release occurred when arousal by music reached its peak, as reported by the subjects and measured by the activation of their autonomic system. Viewing pictures of a person who you love decreases pain by activating the nucleus accumbens, the amygdala and the frontal cortex (Younger et al., 2010). Some dopaminergic neurons in the reward pathway respond to aversive stimuli: things that we dislike, like pain and distress. The activation of some neurons in the nucleus accumbens with dopamine receptors was correlated with the emotional quality of pain (Scott et al., 2006). The front (rostral) part of the shell of the nucleus accumbens reacts to things that we like, while its back (caudal) part reacts to aversive stimuli (Hurley et al., 2017). A review paper (Salamone and Correa, 2012) objected to the name of reward pathway. They said that it is really a motivation pathway because it mediates sustained effort to achieve a goal. Another review (Paredes and Agmo, 2004) argued that dopamine is not important for sexual motivation or sexual reward. Even though this issue remains controversial, I would say that there is strong evidence that the reward pathway is involved in both pleasure and pain. However, scientists use the more precise terms reward for pleasure and aversion for pain. Dopamine receptors There are five receptors for dopamine, D1 through D5 (Seeman and Van Tol, 1994). They are the proteins in the membrane of neurons to which dopamine binds to deliver its signal. The five receptors are divided into two groups: D1-like receptors include D1 and D5 receptors, while D2-like receptors are D2, D3 and D4. The dopamine receptors most important in the reward pathway are D1 and D2 (Wise and Robble, 2020). About half of the neurons of the nucleus accumbens have D1 receptors, which have low affinity for dopamine. This means that their full activation requires high concentrations of dopamine. The other half of these neurons have D2 receptors, which have high affinity for dopamine. This means that relatively low concentrations of dopamine in the nucleus accumbens are able to activate most of the D2 receptors. Dopamine release The key to distinguish the effect of addictive drugs on dopamine from the effect of behaviors like masturbating, watching porn or playing video games resides on somewhat obscure concepts: tonic and phasic release of dopamine. Dopamine, like other neurotransmitters, is released when action potentials in the axon of the dopamine neuron reach a presynaptic terminal. This is a swelling separated by a small gap from the postsynaptic terminal containing the dopamine receptors. In the presynaptic terminal, dopamine is loaded into synaptic vesicles. When an action potential reaches the presynaptic terminals, some of these vesicles fuse with the membrane, releasing dopamine that then crosses the synapse and binds to the dopamine receptors in the postsynaptic terminals. Dopamine does not hang around the synapse for long. There are proteins called dopamine transporters (or reuptake systems) that take dopamine out of the synaptic space and put it back into the presynaptic terminal. Then dopamine gets quickly loaded back into the synaptic vesicles. Tonic dopamine release Neurons fire action potentials in different patterns. Tonic firing is the simplest pattern. It consists of single action potentials separated by time intervals of 150 to 500 milliseconds (ms). A ms is a thousandth of a second, so 500 ms is half a second. Tonic firing releases small amounts of dopamine that binds to D2 receptors, which present not only in the synapse, but all over the postsynaptic neuron. Tonic release of dopamine is not triggered by sensory stimuli from the environment, but controlled by stress and hormones related to feeding, like leptin, insulin and ghrelin (Wise and Robble, 2020). Tonic dopamine release controls the motivational state of the individual, its willingness to exert an effort to achieve a goal. A sustained rate of tonic release keeps basal dopamine levels high, so that D2 receptors are activated. This leads to a state of contentment and satisfaction. When tonic firing is low, dopamine falls below the levels at which it activates the D2 receptors. This creates a state of uneasy that drives the individual to seek something to relieve it. Based on previous learning, the person gets motivated to find a reward (food, sex, a work goal) that would increase tonic dopamine release again. For example, feeding hormones may cause a drop in tonic dopamine release, motivating the individual to seek food. Phasic dopamine release Burst firing of action potentials is more complex. It consists of several groups (bursts) of action potentials at high frequency - up to 100 Hz, which means one action potential every 10 ms. Burst firing changes synapses by the process of synaptic plasticity, which is how the brain stores memories. Synaptic plasticity is composed of two opposing mechanisms: long-term potentiation (LTP), which increases the efficacy of neurotransmission, and long-term depression (LTD), which decreases it. Burst firing of dopaminergic neurons induces phasic dopamine release. Phasic means intermittent: a lot of dopamine is released very quickly during each burst of action potentials. This increases dopamine concentrations at the synapse so much that the D1 receptors get fully activated. Together with the burst of action potentials, they induce LTP in these synapses, recording the memory of the rewarding stimulus. Some of these synapses are in the prefrontal cortex or the anterior cingulate cortex, where they drive future decisions. Some of this dopamine spills out of the synapse and activates D2 receptors. If the D2 receptors are in the bodies of the neurons, this dampens craving. But when the D2 receptors are in nearby synapses, the lower concentrations of spillover dopamine induce LTD in them. These synapses are less efficacious in the future. This sets a signal/noise contrast between the synapses activated by a rewarding stimulus and those unrelated to it, increasing learning. Phasic dopamine release is driven by sensory stimuli related to rewards (pleasure) or aversion (pain). They are delivered to the VTA-accumbens pathway from brain regions that assign a positive or negative emotional value to sensory signals. For example, the amygdala may assign fear to a perception, or the insula may assign pleasure to another one. How dopamine mediates addiction to cocaine and amphetamines This may seem very technical, but the difference between tonic and phasic dopamine is essential to explain why drugs are addictive and behaviors like watching porn or masturbating are not. Let’s start with cocaine. It acts by blocking the reuptake of dopamine: the proteins that transport dopamine back into the synaptic terminals to end its effect. When neurons cannot capture back dopamine, its spillover to D2 receptors outside the synapse during phasic dopamine release increases considerably. Even tonic dopamine release causes higher levels of dopamine around the neurons. Cocaine increases 3 to 5 folds basal level of dopamine in the nucleus accumbens (Wise and Robble, 2020). But equally important is that these high levels of dopamine are present for long periods of time, for as long as we feel the effect of cocaine. Exposed to too much dopamine for long periods of time, the D2 receptors are downregulated: taken out of the membrane and degraded. So now there are less D2 receptors to signal satisfaction, leading to a state of craving. At the same time, the pleasure produced by cocaine sends a signal through D1 receptors that creates an association of cocaine with reward. This, together with the state of craving induced by the downregulation of the D2 receptors, is what drives the compulsive seeking of the drug that constitutes addiction. Amphetamine and methamphetamine acts in a similar way as cocaine, except that they not just inhibit the dopamine transporter, they reverse it! They also release dopamine from the synaptic vesicles. This results in increases in extrasynaptic dopamine even larger than those produced by cocaine. Notice that the increases in dopamine produced by cocaine and amphetamines are not mediated by changes in either tonic or phasic dopamine release. They are not related to behavioral rewards or aversions. It is an unnatural interference that completely messes up the reward pathway. How dopamine mediates addiction to opioids Opioids like heroin, morphine, fentanyl and oxycodone (the infamous OxyContin that caused the opioid epidemic in the USA) act by a different mechanism. Neurons that release the neurotransmitter GABA are the main brake system in the brain. GABA is an inhibitory neurotransmitter that reduces action potential firing in other neurons. There are GABA-releasing (GABAergic) neurons that make synapses with the dopamine neurons of the reward pathway, providing a negative feedback. When there is too much release of dopamine in the nucleus accumbens, GABAergic neurons that go to the VTA get activated, decreasing their firing and thus dopamine release. These GABAergic neurons contain mu-opioid receptors, which are the site of action for the opioid drugs that I listed above. When these opioid receptors are activated, GABA release is decreased. This relieves dopamine release from its inhibition, increasing it - a phenomenon called disinhibition. That is how opioids increase dopamine release in the reward pathway (Johnson and North, 1992; Saigusa et al., 2017, 2021). As in the case of cocaine and amphetamines, the resulting increases in dopamine are sustained and lead to the downregulation of D2 receptors, setting a state of craving. In addition, the abnormal activation of the mu-opioid receptors by the opioid drugs seems to induce long-term changes in the GABAergic neurons that reduce their ability to keep dopamine release in check. This may explain why opioids are even more addictive than cocaine. Curiously, endorphins - the peptides that naturally activate opioid receptors - do not produce addiction (Stoeber et al., 2018). The reason for this is complicated. Endorphins are quickly degraded by enzymes called peptidases (Song and Marvizon, 2003), and this limits the amount of time that they have to activate the opioid receptors. Another reason is that opioid receptors send different signals to the inside of the cell depending on whether they are activated by endorphins or by drugs. The intracellular signals sent by endorphins end the action of the mu-opioid receptors by internalizing them to the inside of the cell, while morphine and other drugs do not produce mu-opioid receptor internalization (Keith et al., 1996; Stoeber et al., 2018). This is important because it means that natural stimuli that release endorphins - like sex and exercise - do not produce addiction, even though endorphins activate mu-opioid receptors just like morphine and heroin. Cannabis Delta9-tetrahydrocannabinol (THC) and cannabidiol (CBD) are two amongst over a hundred psychoactive compounds found in marihuana. They act on CB1, CB2 and GPR55 receptors (Lauckner et al., 2008; Pertwee, 2008). The natural ligands of CB1 and CB2 receptors are the endocannabinoids anandamide and 2-arachinodylglycerol (2-AG). They are called retrograde neurotransmitters because they signal the opposite way than regular neurotransmitters: they are synthesized in the postsynaptic terminals and diffuse to the presynaptic terminal, where they inhibit neurotransmitter release. Like opioids, cannabinoids inhibit GABA release onto dopamine neurons in the reward pathway, increasing dopamine release by disinhibition (Szabo et al., 2002). However, cannabis is much less addictive than opioids and does not produce withdrawal (Wise and Robble, 2020). Several things may explain this. CB1 receptors also inhibit glutamate release onto the dopamine neurons, which increases dopamine release. So, in this case, cannabinoids inhibit dopamine release, moderating their effect on the GABAergic neurons. Cannabinoids increase phasic dopamine release (Wise and Robble, 2020), rather than its tonic release. They also interact with endorphins to increase “liking” instead of “wanting” (Mitchell et al., 2018). CBD, acting on CB2 receptors, decreases addiction to cocaine (Galaj et al., 2020). Other addictive drugs Other addictive drugs have their own mechanisms (Wise and Robble, 2020). Alcohol is addictive when taken regularly in large amounts. Unlike other drugs, its effects on the brain are not mediated by a particular neurotransmitter receptor, but by its interaction with many receptors. These include glycine receptors, serotonin 5-HT3 receptors and nicotinic acetylcholine receptors. Alcohol produces only small increases in basal dopamine levels, but seems to increase phasic dopamine release. Still, alcoholics show a downregulation of D2 dopamine receptors similar to that produced by cocaine, amphetamines and opioids. Nicotine - the psychoactive substance of tobacco - is an agonist of nicotinic acetylcholine receptors, some of which are in dopaminergic neurons of the VTA. Nicotine increases dopamine release from these neurons. In the long term, it downregulates D2 dopamine receptors. Benzodiazepines (Valium) and barbiturates (pentobarbital) act by modulating GABA-A receptors, increasing the inhibitory effects of GABA. They seem to disinhibit dopamine release, like the opioids. Why natural stimuli induce dopamine release, but not addiction Let’s now examine how some behaviors considered addictive impact the VTA-nucleus accumbens dopamine pathway. These things include (Potenza, 2006, 2014): food: eating sweets and other tasty foods (Lindgren et al., 2018); sex: masturbating, watching porn, reading romance and erotica, fetishism, kink; playing: video games, gambling; social interactions: social media, anxious attachment, obsessive love (Burkett and Young, 2012); shopping and shop-lifting; self-harm, like cutting; exercise: any sport done in excess; work: workaholics. These are all natural activities. Although video games and social media depend on the invention of the computer and the internet, playing, gossip and social interactions have always been human activities. The same can be said about sex. People have masturbated, had sex, and watch others have sex since the dawn of humanity. Living today is much less dangerous and scary that in ancient times. It’s only that sensory stimulation has been increased by tastier foods, more appealing sexual images, more exciting games, etc. Strong sensory stimuli engage the reward pathway. However, they still do that by inducing phasic dopamine release. This is completely different from the prolonged elevations of basal dopamine levels produced by psychostimulants like cocaine and amphetamines. Neither does it mess with GABAergic inhibition of dopamine release, like opioids do. Natural stimuli also fine-tune tonic dopamine release to drive our motivations as we cycle through desire and satisfaction. Therefore, the stimuli provided by modern technology are not qualitatively different, in terms of dopamine release, from the old rewards with which we evolved. There is no reason to think that these activities would produce the enormous craving and withdrawal syndromes that addictive drugs produce. Still, it is true that some people develop strong compulsions to gamble, eat in excess or watch porn. However, this is better explained as an excessive tuning of the dopamine system towards one specific reward - gambling, tasty foods, exciting sex, etc. - and not an abnormal hijacking of the reward pathway, as drugs of addiction do. Is sex addictive? Unfortunately, science was often used in the past to justify puritanism and sexual repression. Even today, excessive sexual desire is considered a disease, termed Don Juanism and satyriasis in men and nymphomania in women. And let’s not forget that, for the longest time, homosexuality was considered a mental disorder. Some contemporary papers (Blum et al., 2015) continue this tradition by assuming that departures from culturally approved sexual norms are “maladaptive” and need to be cured. Thus, Bloom et al. define sexual addiction as “any compulsive sexual behavior that interferes with normal living and causes severe stress on the family, friends, loved ones, and one's work environment.” However, the severe stress may be due to family, friends and co-workers refusing to accept unconventional forms of sexuality, as it still happens with homosexuality. The problem, then, is not with the sexual behavior in itself, but with the bigoted attitudes of society. Indeed, in their review of the literature, Bloom et al. found no evidence that hypersexuality produces any withdrawal symptoms when the sexual activity is stopped. They state that “the prevalence rates of sexual addiction-related disorders range from 3% to 6%”, but these include “excessive masturbation, cybersex, pornography use, aberrant sexual behavior with consenting adults, telephone sex, strip club visitation, and other addictive behaviors.” However, these are behaviors accepted as normal by most people in Western societies. Calling these behaviors addictive is based more on their puritanical assumptions than on scientific evidence. Other scientists align better with modern sex-positive views by showing that hypersexual behavior is just one extreme of the normal range of sexual desire (Steele et al., 2013; Prause et al., 2017). Indeed, the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DMS-5) rejected the concept of sexual addiction (Potenza, 2014). Addiction or compulsions? Whether some behaviors are addictive continues to be hotly debated in the scientific community (Potenza, 2006, 2014). An emerging view is that compulsive behaviors like excessive eating, gambling, gaming and watching porn are not addictions but reflect an underlying deficit in the reward pathway that causes these individuals to be always craving something. This underlying disorder in the reward pathway may be genetic, produced by a disease, or derived from trauma. Only by addressing its true cause can these persons be freed of their basic craving. Then, curing them of one “addiction” only serves to switch their compulsion to another behavior. For example, when “sex addicts” do not have access to sex, they start smoking or eating in excess. Trying to cure these people of one compulsive behavior has the danger of switching them to consuming addictive drugs, a situation much worse than the original problem. Closing thoughts There is much more to the brain than the VTA-nucleus accumbens reward pathway. Like any other system in the brain, it doesn’t work in isolation. Its function is deeply connected to sensory systems that weigh the importance of incoming information, and to cortical systems that plan actions. Trying to view human behavior through the narrow window of addiction is incredibly short-sighted. Yes, there are many things in the modern world that strive to capture our attention, but they don’t have the hold on our will that drugs have over addicts. Of course, obsessively seeking pleasure can be a problem. But so is shackling ourselves to the repression of sex and other pleasures of life. Too much self-discipline, guilt and shame can cause much suffering by propelling us on an ego-driven chase of success, money and fame. Puritanism has been in the collective minds of Americans since the start of this nation. It gave birth to the Prohibition and to the War on Drugs, misguided attempts to address alcoholism and drug addiction through criminalization. One reason why books like Dopamine Nation are so successful is because the narrative of sin and redemption — which underlies the cycles of abuse and sobriety of many addicts — is so deeply imbedded in the American psyche. In fact, calling porn and video games addictive undermines the importance that we should give to the tragic problem of drug addiction. The current opioid epidemic in the United States was started in 1996 by Purdue Pharma, ran the Sackler family, with its aggressive marketing of OxyContin to American doctors. It was not caused by people chasing pleasure. Its toll is over 300,000 deaths. Nobody has died from watching too much porn or playing video-games. Saying that porn, masturbation, gaming and cell phones are problems similar to drug addiction is simply ridiculous. It is a slap in the face of the millions of people who have lost loved ones to real addictions. I hope that in this article I have shown that the neuronal mechanisms that underlie drug addiction are quite different from those that motive us to do anything else in our lives. Including enjoying pleasures like games, porn, sex and love. References Blum K, Badgaiyan RD, Gold MS (2015) Hypersexuality Addiction and Withdrawal: Phenomenology, Neurogenetics and Epigenetics. Cureus 7:e348. Burkett JP, Young LJ (2012) The behavioral, anatomical and pharmacological parallels between social attachment, love and addiction. Psychopharmacology (Berl) 224:1-26. Galaj E, Bi GH, Yang HJ, Xi ZX (2020) Cannabidiol attenuates the rewarding effects of cocaine in rats by CB2, 5-HT(1A) and TRPV1 receptor mechanisms. Neuropharmacology 167:107740. Hurley SW, West EA, Carelli RM (2017) Opposing Roles of Rapid Dopamine Signaling Across the Rostral-Caudal Axis of the Nucleus Accumbens Shell in Drug-Induced Negative Affect. Biological psychiatry 82:839-846. Johnson SW, North RA (1992) Opioids excite dopamine neurons by hyperpolarization of local interneurons. J Neurosci 12:483-488. Keith DE, Murray SR, Zaki PA, Chu PC, Lissin DV, Kang L, Evans CJ, von Zastrow M (1996) Morphine activates opioid receptors without causing their rapid internalization. Journal of Biological Chemistry 271:19021-19024. Kotler S, Mannino M, Kelso S, Huskey R (2022) First few seconds for flow: A comprehensive proposal of the neurobiology and neurodynamics of state onset. Neuroscience & Biobehavioral Reviews 143:104956. Lauckner JE, Jensen JB, Chen HY, Lu HC, Hille B, Mackie K (2008) GPR55 is a cannabinoid receptor that increases intracellular calcium and inhibits M current. Proc Natl Acad Sci U S A 105:2699-2704. Lembke A (2021) Dopamine Nation: Finding Balance in the Age of Indulgence. New York: Penguin Random House. Linden DJ (2012) The Compass of Pleasure: How Our Brains Make Fatty Foods, Orgasms, Exercise, Marijuana, Generosity, Vodka, Learning, and Gambling Feel So Good: Penguin Books. Lindgren E, Gray K, Miller G, Tyler R, Wiers CE, Volkow ND (2018) Food addiction: A common neurobiological mechanism with drug abuse. FBL 23:811-836. Mitchell MR, Berridge KC, Mahler SV (2018) Endocannabinoid-Enhanced "Liking" in Nucleus Accumbens Shell Hedonic Hotspot Requires Endogenous Opioid Signals. Cannabis Cannabinoid Res 3:166-170. Olds J (1958) Self-stimulation of the brain; its use to study local effects of hunger, sex, and drugs. Science 127:315-324. Olds J, Milner P (1954) Positive reinforcement produced by electrical stimulation of septal area and other regions of rat brain. J Comp Physiol Psychol 47:419-427. Paredes RG, Agmo A (2004) Has dopamine a physiological role in the control of sexual behavior? A critical review of the evidence. Prog Neurobiol 73:179-226. Pertwee RG (2008) The diverse CB1 and CB2 receptor pharmacology of three plant cannabinoids: delta9-tetrahydrocannabinol, cannabidiol and delta9-tetrahydrocannabivarin. Br J Pharmacol 153:199-215. Potenza MN (2006) Should addictive disorders include non-substance-related conditions? Addiction 101 Suppl 1:142-151. Potenza MN (2014) Non-substance addictive behaviors in the context of DSM-5. Addict Behav 39:1-2. Prause N, Janssen E, Georgiadis J, Finn P, Pfaus J (2017) Data do not support sex as addictive. The lancet Psychiatry 4:899. Saigusa T, Aono Y, Waddington JL (2017) Mechanisms underlying δ- and μ-opioid receptor agonist-induced increases in extracellular dopamine level in the nucleus accumbens of freely moving rats. J Oral Sci 59:195-200. Saigusa T, Aono Y, Waddington JL (2021) Integrative opioid-GABAergic neuronal mechanisms regulating dopamine efflux in the nucleus accumbens of freely moving animals. Pharmacol Rep 73:971-983. Salamone JD, Correa M (2012) The mysterious motivational functions of mesolimbic dopamine. Neuron 76:470-485. Salimpoor VN, Benovoy M, Larcher K, Dagher A, Zatorre RJ (2011) Anatomically distinct dopamine release during anticipation and experience of peak emotion to music. Nat Neurosci 14:257-262. Scott DJ, Heitzeg MM, Koeppe RA, Stohler CS, Zubieta JK (2006) Variations in the human pain stress experience mediated by ventral and dorsal basal ganglia dopamine activity. J Neurosci 26:10789-10795. Seeman P, Van Tol HH (1994) Dopamine receptor pharmacology. Trends Pharmacol Sci 15:264-270. Song B, Marvizon JC (2003) Peptidases prevent m-opioid receptor internalization in dorsal horn neurons by endogenously released opioids. J Neurosci 23:1847-1858. Steele VR, Staley C, Fong T, Prause N (2013) Sexual desire, not hypersexuality, is related to neurophysiological responses elicited by sexual images. Socioaffect Neurosci Psychol 3:20770. Stoeber M, Jullié D, Lobingier BT, Laeremans T, Steyaert J, Schiller PW, Manglik A, von Zastrow M (2018) A Genetically Encoded Biosensor Reveals Location Bias of Opioid Drug Action. Neuron 98:963-976.e965. Szabo B, Siemes S, Wallmichrath I (2002) Inhibition of GABAergic neurotransmission in the ventral tegmental area by cannabinoids. Eur J Neurosci 15:2057-2061. Wise NJ, Frangos E, Komisaruk BR (2017) Brain Activity Unique to Orgasm in Women: An fMRI Analysis. The journal of sexual medicine 14:1380-1391. Wise RA, Robble MA (2020) Dopamine and Addiction. Annu Rev Psychol 71:79-106. Wise RA, Jordan CJ (2021) Dopamine, behavior, and addiction. J Biomed Sci 28:83. Younger J, Aron A, Parke S, Chatterjee N, Mackey S (2010) Viewing pictures of a romantic partner reduces experimental pain: involvement of neural reward systems. PLoS One 5:e13309.

The beauty of dating an amputee I have to confess that the first time I saw her stump I felt a bit disgusted. The skin was loose and wrinkled, full of scars. It was kind of soft to the touch and it had a peculiar smell, maybe because of all that time inside the rubber envelop of her orthopedic leg. We made love, anyway. Erin, despite having her left leg amputated just below the knee, is a beautiful and sexy woman. She has the willowy body of a teenager, well-defined muscles in her arms, shoulders and back, a flat belly, small delicious breasts and an exquisite ass - as can be seen in this picture I took while she was sleeping. Soon enough, I became aware that Erin is an expert in the erotic arts. Her desire gets easily turned on and then she gives herself entirely to you, to everything you want to do to her, opening her body with a fiery enthusiasm, without fears or traumas. We rolled in bed testing every position, every perversion, our naked bodies covered by a sheen of sweat, not knowing if it was hers or mine. As a prerequisite for our relationship, I required of her the most rigorous honesty: I can’t stand lies, and I hold secrets only when strictly necessary. So the following day I didn’t want to hide what I had felt. “I had some trouble with your stump”, I confessed. Her answer was totally unexpected: “And you think I don’t? It’s been more than twenty years since I lost my leg and I still haven’t gotten used to it”. That moved me. If I didn’t like her stump I always had the option of leaving her. But she didn’t. She always would have to make love putting just one foot up in the air, trying not to look at her stump, hoping that the lover of the occasion wasn’t bothered too much by her incomplete body. I think it was then when I started falling in love with Erin. Little by little, in subsequent dates, Erin told me her story. When she was a teenager she loved to run. She would spend hours jogging between the houses of Burbank, just at the foot of the steep San Gabriel mountains that mark the horizon of Los Angeles. She ran marathons and even won a few medals. She had beautiful legs, strong and slender. Once, when she needed money, she signed up to show them off in a strip-tease show, and they were a big hit. She was twenty five when disaster stroke. At sunset, on a fine September day, a friend asked her to take her home in her scooter. A car appeared out of nowhere, making an illegal left turn, and slammed into them. Erin found herself lying on the street with her left foot torn apart, spitting her teeth on the asphalt. Her friend came out of the accident unscathed. Erin spent several months in the hospital, until Christmas. The doctors did everything they could to save her foot, but to no avail. Erin told her mother that she’d rather die than to let them cut away her leg. She couldn’t live without being able to run. In the end, it was the stench of the gangrene that changed her mind: an odor indescribably foul that was with her night and day. She thought she was going crazy, particularly knowing that it came from her own body. One day the doctor came into her room and looked at her without saying anything. “It has to go, doesn’t it?”, said Erin. The doctor nodded. But that was not the end of it. Even after the amputation, the gangrene continued to spread. The doctors had to cut her leg over and over again, every time a bit higher, getting closer to the knee. Her fibula had to be completely extirpated and only a little piece remained of her tibia. To cover her stump, they had to remove skin from the front of her thighs, leaving two rectangular patches of whitish skin that resemble the mended pants of a beggar. One day, joking, I told her that she looked like a scarecrow. For a while, she signed her e-mails “scarecrow”. Erin had no money to buy an orthopedic leg, so she made herself a wooden leg, like a pirate’s leg, that she tied to her stump with leather straps. Her workmates gave her stickers and tags that she placed over the wooden leg until it was completely covered. Now she has a nice orthopedic leg that allows her to walk normally. One day we went to the beach and I convinced her to run with me at the edge of the surf. Yes, Erin can still run, but she doesn’t do it unless necessary because the repeated impact can crack the plastic of her orthopedic leg, and she doesn’t have enough money to replace it. I never thought that I would end up with a lover with a broken body. I never thought I would come to like her so much. What is beauty, in the end? There is a beauty that is easy to see, the one that they instill in you in movies, magazines and advertisement. The soft, unblemished skin. The symmetrical body. The shapely muscles with that thin layer of fat that soften the corners of the female body. That type of beauty is just an animal reflex; in the end everything comes to attraction to whatever reveals health and revulsion to whatever indicates disease. But there is another type of beauty that is exclusively human: the beauty of acting the right way, of living an ethical life. The beauty of a story that touches something deep inside you. That’s what I see in the mutilated body of Erin: her story, the courage that she summoned to face never been able to run again, having to spend the rest of her life dragging a leg made of plastic and steel. Now, when we make love I kiss her scars, I caress her stump. She tells me it’s quite sensitive, because all the nerves that used to ran all the way to her feet had to end there. Yes, Erin is beautiful, and not only because of her slender body, her flat belly and her exquisite ass. She is beautiful because of her missing leg, the rectangular patches of whitish skin in her thighs and her scars. Those things speak of her story, her suffering and her ability to overcome it. They show that her good mood and her easy smiles are her conquests, her triumph over bad luck. They show that she has more strength that most of us will ever have. I wrote this article in 2013, while I was dating Erin. She loved it and showed it to all her friends. She left me in June that year. Soon afterwards, in November, she took her life. It seems that what she told her mother was true: it was too painful for her to live without her leg.

My early encounters with sea creatures, sexual abuse and death [TW: Child sexual abuse] I woke up early. Thin sunbeams filtered through the cracks in the blinds, announcing a beautiful summer day. I slid down from my top bunk bed and, not wanting to wake up my brothers, I grabbed my swimsuit, a T-shirt and my beach slippers and put them on quietly. I was thirteen. The sun was still low over the pine trees above the house. The bay was calm, an incipient breeze changing its color from silver to deep blue. It was going to be a hot day. Nobody was up yet, so I decided to go for a walk. I wandered through fields of cabbage and corn until I came to the rocks by the water's edge. Not far offshore, in his wooden boat brightly painted white, brown and blue, was the octopus fisherman. Octopus is a delicacy in Galicia, the national dish. It is served on a thick wood plate, seasoned with olive oil, coarse salt and spicy paprika. I loved to eat it, but I was also fascinated by the animal itself. I had just learned to catch it. With my mask, snorkel and fins, I would swim over the sandy bottom looking for odd objects: a rubber boot, a pot, a tire. Then I would dive and check inside for octopus. More often than not, I would find one. Then I would wrestle it to the shore, kill it and proudly present it to my mother to cook. The old fisherman used entirely different techniques to catch octopus. He would never get in the water. Like most Galician fishermen, he didn’t even know how to swim. He carried long poles with a hook at the end. When he spotted an octopus on the bottom, he would quickly get one on his poles, hook the octopus and haul it into his boat. Sometimes the octopus would get into a crack in the rocks and stubbornly hold to it with all the considerable strength of its tentacles and suction cups. Then a fight would ensue, the fisherman pulling with his pole this way and that and the octopus holding on for dear life. * * * One day I witnessed one of these struggles while lying lazily on a towel on the beach. The fisherman fought for over half an hour and still couldn’t get the octopus. I grabbed my mask, snorkel and fins and got in the water, wanting to take a closer look at the struggle. There was a large rock on the bottom. The hook of the fisherman’s long pole was digging under it. There must be an octopus under there, I thought. I asked him if he needed help, but he just muttered something incomprehensible in Galician. But the octopus was giving no sign of giving up. Finally, I couldn’t stand it anymore. I took a deep breath and dove toward the rock. Bracing with my knees on the bottom, it wasn’t hard to overturn the rock. The octopus came out and took off swimming at full speed, opening and closing its tentacles looking like a little ghost. I went back to the surface for air. “Look what I have done!” I thought, “I have lost this poor fisherman his catch.” Desperately, I swam on the surface following the octopus, which was heading for deep water. I dove again. If the octopus was as smart as some people think it is, it would have just keep on swimming and I would have never been able to catch it. Instead, it opened its tentacles on the bottom and waited for me. I grabbed it and head back to the surface. It was a big one. It wrapped its tentacles around my arm all the way to my neck, pulling hard to slide between my fingers. I knew it just wanted to get away, but I started to get scared. Then I looked up and saw the fisherman in his boat. He grabbed the octopus and peeled it off me. “I’m glad I could get you that octopus,” I told him after I climbed into his boat. “That’s your octopus now,” he said. “Take it home to your mom.” * * * I used to ride with the octopus fisherman in his boat, watching him peek into the water to find an octopus where I could see just rocks. Another way he had to catch his prey was to drag a line to which he had attached a small rock with a crab and hooks on top. The octopus would try to get the crab and get hooked. He taught me the names of all the beaches in the bay and a lot of things about the sea. At the end of the morning, he would pull his boat to the beach and the beachgoers would gather around and bid for his catch. So when that morning he rowed his boat backwards to the rocks to let me in, I didn’t think twice. I climbed on board and sat on the prow as he rowed back out on the bay. I tried to start a conversation about fishing, but he didn’t seem in the mood for it. Then something really weird happened. He pulled in the oars and came to where I was. He started touching me over my skimpy swimsuit. I couldn’t believe what was happening. “What are you doing?” I said. “Whoa, you have a big one!” he said. That was completely ridiculous. I haven’t reached puberty yet. I had the penis of a child. It didn’t even care if it was big or small. “Do you want to touch mine?” I couldn’t imagine anything more repulsive than to touch that old man’s cock. “No! Stop! Leave me alone!” “Do you want to go to shore?” he said in Galician. Go to shore and do what? Go to a hiding place so he could continue touching me? As it was, anybody looking out from the beach could see us. But there was nobody there. “Stop! Stop, or I’ll jump in the water!” He took a step back, as if to consider what I had said. Then he started again. I quickly took off my T-shirt and my slippers and dove headfirst into the sea. The water was cold. I come to the surface and looked at him. He could row his boat much faster than I could swim. Would he fish me out of the water as if I were an octopus? But he just stood there, looking at me with apparent indifference. I swam in a perfect crawl straight to the beach. I wanted to slip quietly back into my room and change, but my mother saw me walking in, barefoot and wet. “You have been swimming already?” “Yeah, the water is nice,” I muttered, and went upstairs. * * * What was that old man thinking? How could he dare? He was just a poor man. My father was a local authority. If I told, I could get him into a lot of trouble. He would probably wind up in jail. But I couldn’t stand the thought of seeing that free spirit in jail. For me, he symbolized the freedom and the wildness of the sea. Even what he had done to me represented that careless freedom. Those were still the dark years of the Franco dictatorship. I didn’t know anything about sex, nobody had told me. Obscure desires had started to awaken inside me. I didn’t understand any of that. It scared me. The priests told us a few things, but they were always unclear, shrouded in secrecy and sin. Perhaps the old fisherman could explain it to me, the same way that he had explained the way of the octopus. But not if he was going to touch me like that again. It slowly dawned on me that I could never ride in the old fisherman’s boat again. * * * Later on that day, I saw the fisherman pulling his boat on the beach. He had a system to pull his heavy wooden boat out over the tide line. He lay the oars on the sand and put a round log across them. Then he rolled the boat over the oars, using the round log as a wheel. He repeated the process several times until the boat was on the white dry sand, out of the reach of the high tide. Some beachgoers often helped him, but he was perfectly capable of doing it on his own. While the bid over the catch started, I surreptitiously grabbed my slippers and T-shirt from the boat and walked away. * * * He must have done other boys. One day I was walking on a cove that could only be reached by hiking through thorny gorse and blackberry bushes. There I saw him walking out of a shack with a teenage boy. I pretended that I didn’t see them. The locals never said much about him. He had no wife, no children, no family that I knew of. He seemed content and self-sufficient. He looked as old as the world, with his short white hair and his wrinkly face, but there was no way to know how old he really was. Perhaps he didn’t know himself. I saw him once dancing at a local fiesta, alone. He jumped and pranced with a vitality and abandon that I envied. * * * I was already attending college when I heard that the octopus fisherman was dying. Stomach cancer, they said. I made discreet inquiries and found the way to his place. It was an old stone house surrounded by an unkempt garden, but there were peach trees and fig trees and plum trees, the fruit still green in the early days of summer. I knocked on the door, called, then walked in. The inside of the house was just a large single room, with a high ceiling, a wooden floor and walls of naked granite blocks. There was a large bed in the middle. The old fisherman was laying on it, his belly swollen. Other than that, he looked as he always did. I sat on a chair by him and asked him how he was. He knew he was dying. I asked him if he was afraid of death. He said he was afraid of the pain. I asked him if he believed in an afterlife, in God. I had abandoned Christianity a few years back, when I was fifteen, and now I was exploring yoga and Eastern mysticism. But he didn’t seem to care about religious belief, he just wanted the pain to be over. I didn’t mention the incident on the boat. I still didn’t have the words to talk about sex, much less sexual abuse. A few days later, my father told me that the octopus fisherman had died. He asked me if I wanted to go to his funeral. I said no. I had already said my goodbyes to the old man.

How I left Catholicism while attending an elite school ran by Opus Dei Moving to Madrid My childhood in the Spanish town of Santiago the Compostela ended when I was 15, when my parents, my seven siblings and I moved to Madrid. That heralded a momentous change in my life. It was not just that I was in the middle of puberty. The intellectual changes that had been brewing inside of me came to a head. We had a nice apartment in Santiago, in professor housing in the middle of the campus, surrounded by gardens and sport facilities. But our new home in Madrid was downright luxurious: a huge flat facing the Park of Berlin, in a modern part of the city. It had so many bedrooms that I got to have a room of my own. My Opus Dei High School My father had been telling my brothers and me that we would go to the Instituto Ramiro Maeztu, a public school walking distance from our new home. However, when we arrived in Madrid, we found that plans had been changed without our knowledge. We were enrolled in the school of El Prado, ran by the private organization Fomento de Centros de Enseñanza, controlled by the Opus Dei. It was a boys-only school. My sisters would go to Montealto, a girls-only school run by the same organization. As I described in the Part 1 of this series, Opus Dei is a conservative Catholic organization that controlled politics and wealth in Spain during the last part of the Franco dictatorship. My siblings and I had been groomed by this organization since childhood. However, the school we attended in Santiago de Compostela, although also private and boys-only, was not run by Opus Dei. Now, we would have Opus Dei in our family, at school and in our social circle. We were invited to join Club Jara, a boys' club similar to the Club Senra that I frequented in Santiago. El Prado school was in Mirasierra, a wealthy colony in the outskirts of the north of Madrid. It was far from home and not easily accessible. Most students got there by school bus. However, one of the perks of my father’s new government position was an official car, complete with uniformed chauffeur, flag and government license plates. Everybody would recognize it when we stepped out. I was embarrassed. However, I soon find out that we were not the only ones being driven to school in an official car. Some of my classmates also were the sons of government officials, military and entrepreneurs. I was in an elite school. The academic year had already started at the school. We were late because of the move. I joined in the middle of class. I had grown a beard during the summer, so my new classmates thought that I was a new teacher sitting the class. When they found out that I was the new kid in town, they were fascinated. I feared that I was not going to be able to catch up with the curriculum of such an elite school. I was used to being the first of my class in Santiago. Now, I found the mathematics class incomprehensible. The Literature teacher was an aggressive priest prone to telling vaguely sexual anecdotes. Physics was challenging. And I found religion class to be the most upsetting. It consisted of going over the dogmas of Catholicism, which made me feel the whole oppressive weight of that religion. However, I soon found out that my classmates felt pretty much the same weight. Nobody understood the math teacher. He was just awful. Suddenly, he changed from algebra to calculus and I found myself in familiar territory. I had a great math teacher in Santiago, and I loved calculus. Soon, I was explaining it to my peers, which made me quite popular. I also got into the habit of picking arguments with the philosophy teacher. My classmates loved these confrontations and cheered me along. I had the good taste of conceding the point before things got ugly, and that earned me the favor of the teacher as well. The first round of exams came. I got good grades. I was on! Growing doubts My discussions with the philosophy teacher were not as frivolous as they seemed, however. They reflected a deep philosophical struggle inside of me. I had always been a good boy: obedient, a good student, always eager to please my demanding father. Being religious was part and parcel of that. That’s why I went to all those retreats of the Opus Dei my father sent me to. I prayed, went to mass and confessed regularly. I didn’t chase girls or masturbate. In fact, I lived in deep sexual repression despite an emergent libido. I had a penchant for mysticism. I loved sitting silently in prayer, gathering my thoughts while I talked to God. I did half an hour of prayer every evening. But I wasn’t feeling it. I didn’t feel any devotion to the Virgin or the saints, and was not even impressed by Jesus. I saw no reason why I couldn’t talk directly to the Big Boss. The problem was that my insatiable curiosity had propelled me to learn a lot about science. It provided a coherent, enormously appealing view of the world that increasingly collided with the dogmas of Catholicism. But it was not just that. I had started reading about yoga, Hinduism, Taoism and Buddhism, and they seemed more attractive as religions than Christianity. I reasoned that being a Christian was a mere accident of my birth. That random occurrence could not determine the truth of a religion. If I had been born in India, I would have been a Hindu. If I had been born in Egypt, I would be a Muslim. And so on. So, the rational thing to do was to examine all religions and then decide which one made more sense. If any. I had tried that the previous summer, while I was at an Opus Dei retreat in Vigo, a port city of Galicia not far from where my parents had a beach house. I decided that I was going to stop being a Christian, to see what it felt like. I even told a priest in confession. He was horrified, but could not provide any satisfactory response to my problem of being a Christian by accident of birth. Or any other of my objections. Another disturbing thing that happened during that summer retreat was that the participants we were invited, as a group, to discuss a philosophical or political subject. However, there was an important caveat: it couldn’t be anything about which the Church had a doctrine. I successively proposed discussing communism, socialism, anarchism, Eastern religions, feminism, only to always came against the same answer. These were things condemned by the Church, so they could not be discussed. I was furious. I had the feeling that Catholicism was a huge intellectual jail in which I could not learn what I wanted and grow intellectually. However, the prospect of staying outside the Church was too scary, so I went back to being a Catholic. If I wandered outside of religion, how was I going to maintain my self-discipline? Wouldn’t I end up becoming a pervert, a communist, a drug addict, like so many youngsters of my generation? I meet a real-life saint During the Holy Week of 1972, I was invited to travel to Rome with the Opus Dei, see the Pope and meet the Father, Monseñor Escrivá de Balaguer, the founder of the Opus Dei. After his death, he was canonized by the Church. So I was about to meet a real saint. I was not impressed by him. He made us wait a long time. Then he told us a silly story about a rich man that gave a lot of his wealth to charity, and a poor man that only had one spoon but was so attached to it that he growled at anybody that looked at it. The moral of the story was that what matters is not how much money you have, but how attached you are to it. It made sense, sort of. But I think Jesus says the opposite in the Gospel. Something about camels and the eye of a needle. Whatever. Escrivá de Balaguer would die three years later, on June 26, 1975. Five months before the death of dictator Franco. But I loved being in Rome. I had been born there, and I lived in that magical city until I was 5. I could still remember some of the places of my childhood. I could speak Italian. Too bad they didn’t let me wander on my own. October 1972: the agony of making a decision Attending those religion classes in the school of El Prado, I couldn’t keep my eyes closed anymore. Cognitive dissonance became too strong. The dogmas of Catholicism rained on my head like blows of a hammer. I could clearly see how they conflicted with my scientific view of the world. Humans were the product of evolution. The mind was just the brain at work. Miracles seemed doubtful, and besides, all religions had them. Looking deeper, religion started to seem like a mental trap. Its arguments were circular. From inside Christianity, it was hard to object to the beliefs, mostly because believing was considered a good thing, and unbelief was a sin. But if you dared to place your point of view outside of religion, it all fell apart. It made no more sense than believing in the ancient Greek gods, or in reincarnation, or that Krishna was the avatar of Vishnu, or that Muhammed was the prophet of Allah. By the time October rolled around, I was in deep distress. I had to decide. I could renounce my heretical views based on science and Eastern mysticism and fully embrace Christianity. Or I could leave Christianity and follow my own spiritual path. The decision seems obvious when I look back at it. But I was 15, barely a child. I had nobody to help me. My parents were in the Opus Dei. My teachers were in the Opus Dei. The whole damned country was a Catholic dictatorship where expressing the wrong opinion (and I had lots of those) could land you in jail. Every evening before dinner, I locked myself in my room for my daily prayer, and cried, torn by my inner struggle. Then I dried my tears and pretended that nothing was happening. I did ask a couple of priests for advice. But our conversations turned confrontational. I even wrote to don Aurelio. His answer came too late. He said that he had always feared that the extremism of Opus Dei was going to turn me away from Christ. But, for me, Opus Dei represented the true face of Catholicism. I couldn’t live like that, so I gave myself a deadline: by the end of October, I would decide. A few things started to come clear. I wasn’t going to stop being a Christian to give free rein to my last and go chasing girls. In fact, I would not abandon any part of my self-discipline. I would continue my daily prayer, studying hard and restraining from masturbation. My reasons for leaving Christianity were purely intellectual. Halloween was unknown in Spain at the time. On that suspicious date, I stopped being a Christian for good. Out of the mental jail The feeling was one of complete freedom. An enormous weight was lifted off me. I felt like I could finally breathe. I could read what I wanted, think what I wanted. Choose my beliefs along the way; discard them when they no longer made sense. There was no feeling of urgency anymore. I was young. I had my whole life in front of me. I could take my time to choose my ideas and my values. Non-believer in the closet However, there was still a lot of fear. How would I tell my parents? Would I dare tell my teachers in that Opus Dei school? Now that I could speak more freely to my classmates, I realized that they were divided into two camps: those who agreed with Opus Dei, and those who opposed it. I had been so careful in hiding my inner conflict that nobody knew on whose side I was on. That made me realize that my new ideas entailed some obligations. I had to help those who thought like me. My discussions with my philosophy teacher took a new edge. And so did my questions to my other teachers. I would carefully choose an idea and put it out there as a question. But it was bait; if you followed it to its conclusion, you would find yourself questioning a dogma. My classmates were not stupid. They soon realized what I was up to. My popularity increased. I found myself in a role that I didn’t know existed: the cool intellectual kid who got the highest grades and thus could not be harassed by the teachers. And so did Opus Dei. And probably my parents. However, much to my surprise, nobody dared to confront me openly. They seemed as afraid of me as I was afraid of them. I was like they knew that my change of heart was so honest, so deeply rooted in well-thought ideas, that confronting it could end up challenging their own convictions. But I was flattering myself. What really happened is that the whole country of Spain was undergoing the same change as me, as the national-catholic dictatorship of Franco slowly fell apart. My guardian angel One strategy of Opus Dei is to place one of their members near you to keep tabs on you and inform his superiors in the organization. That person would become your best friend so that you would confide in them your most intimate thoughts Ironically enough, the name of my guardian angel was Ángel, a common name in Spain. Ángel was my classmate. He got good grades, but regularly seek my help with math and physics. Although he never said, he was a numerary member of Opus Dei. I know now that Opus Dei starts recruiting members when they are 14. In fact, they had tried to recruit me at that age, while I was at that retreat in Vigo. But I was in the midst of my first “crisis of faith”, so it didn’t work out. Ángel and I were both members of Club Jara. That winter, I had fallen in love with skiing, a sport that could be practiced in the Sierra of Guadarrama, barely an hour's drive north of Madrid. Club Jara fleeted a bus every weekend to the sierra, which was my main reasons not to cut ties with that Opus Dei club. I even kept attending their Friday night's prayers, just because I enjoyed singing the Pange Lingua in Latin. If my parents insisted, I went to Sunday mass with them. And they saw me locking myself in my room every evening for prayer, which, in my head, I had started calling meditation. Yeah, I know: I was devious. But it worked quite well. It kept everybody trying to second-guess me. And I really enjoyed the skiing. It was May when Ángel invited me to go on a long bike ride with him. On one of our rest, he started pestering about praying the rosary. Or maybe going to another of those Opus Dei retreats. I could hold it no more. I told I was no longer Catholic, or even Christian. I didn’t expect him to get as surprised as he did. I thought he had already figured it out. He told me I was going to Hell and blah, blah, blah. I just shook my head and laughed. He realized it was hopeless trying to convince me. We just got on our bikes and rode back to Madrid. I knew he would tell Opus Dei, who would tell my parents. I didn’t care. I had left behind my fears. That was the final step of leaving the mental jail in which I had spent my childhood. Preparing for college That was my last year of High School, so I only attended El Prado for one year. The following year was a bridge year in which we were supposed to prepare for college. I was sent to an academy also run by Opus Dei. Despite of that, it was mixed gender. For the first time in my life, I had girls as classmates. I had become good friends with Carlos, a former classmate of El Prado who joined me at the academy. Carlos told me that he had been a member of Opus Dei but had left the organization, becoming a non-believer, like me. We bonded by our common interests in science, ideas and mountaineering. I was reading ferociously: Hindu philosophers like Sri Aurobindo and Swami Vivekananda, Teilhard de Chardin, Zen, Alan Watts, Erich Fromm, Aldous Huxley, Ray Bradbury, Isaac Asimov (the science-fiction and the popular science)… Well, it may have taken me a few more years to work through all these authors. But that should give you an idea of where my mind was heading. Unlike what is common in the USA, students in Spain didn’t get to choose their university. I was assigned to go to the Complutense University of Madrid. But I wanted to get out from the influence of Opus Dei, so I thought that the newer university, called Autonoma, would be better. Besides, it had a great program in biochemistry, which was what I wanted to major on. With some help from my father, I managed to switch. Ángel and I meet again Strangely enough, Ángel emailed a few years ago. It wasn’t hard to find me on the internet, I guess. Why did he contact me? To check if he could bring me back to Catholicism? Was he still trying to be my guardian angel? I told him straight that I was more atheistic than ever. I had cycled through several religions and Christianity was the one I liked the least. He said that it didn’t matter. He was just thinking about me and wanted to see how I was. He was a successful film producer. Sometimes, he even came to LA. Yes, he was still a member of Opus Dei. Imagine that! Being celibate since we were both teenagers. To have none of the wonderful sexual experiences I had. To never have fallen in love. To never had seen your child grow up. “Was it worth it?” I wanted to ask. But I never did. I already knew the answer. We met for lunch a couple times I was in Madrid. He had changed a lot. So, I guess, had I. We didn’t talk about religion - much as I wanted to. But I feared that I couldn’t do that without the conversation turning confrontational. My father’s last years had taught me that it was cruel to challenge somebody’s beliefs. Especially that late in life. The last time we saw each other, he took me to his home and his office. He lived in a house that he shared with several other members of Opus Dei. The main room on the first floor was a beautiful chapel. There was a common kitchen and living room. His bedroom was tiny. It was nice to have a look at modern-day Opus Dei. I guess that’s what he wanted me to do. I ended up telling him my pen name, Hermes Solenzol. I told him to go ahead and read my first novel, warning him that in contained a description of my falling out of faith, a strong criticism of Catholicism, and plenty of sex scenes. He went ahead and read it, anyway. I asked him if he thought that my portrayal of Opus Dei was fair. He said that it mostly was, except for one little detail: my protagonist, Cecilia, would not have confessed to the priest face-to-face, but using a confessionary. In his first emails, Ángel sent me PDF files of the letters I send him from college. I was surprised by the Om signs and all the Hindu mysticism. I was going through the phase that I will describe in the next article of this series. This part of my life is fictionalized in the first part of my novel Games of Love and Kink.