Sex & Relationships

Does Sex Addiction Have Any Basis in Science?

The evidence is not compelling, and science has often been hijacked to legitimize social control.

Things used to be pretty straightforward: You were involved in a stable and fulfilling long-term relationship, but nevertheless the temptations were many and practicing strict monogamy proved way too hard. Eventually, you were caught and you had to decide whether to call it quits or to go back to your partner, admit your full responsibility, beg for forgiveness, and promise that it was never going to happen again. Nowadays, however, there may be a third option: You can claim that you are a victim of sexual addiction, simply unable to manage your sexual urges despite what you know is best for you.

This term has been steadily gaining recognition among the public, helped by several high profile cases of celebrities who checked themselves into "sex addiction rehab" after their infidelities were made public. Self-help groups such as Sex Addicts Anonymous and Sexaholics Anonymous have sprung up in the last few decades, following the 12-step system first made popular by Alcoholics Anonymous. There is even a proliferation of fictional characters from recent movies, novels, and TV series who are described as sex addicts and regularly attend meetings organized by these kinds of groups. The proponents of the concept routinely argue that sexual addiction and substance addiction are analogous syndromes, with both of them rendering the individual a slave to a particular source of gratification at the expense of everything else in his/her life. But is there strong scientific evidence supporting a common physiological basis between these versions of compulsive behavior?

The answer depends strongly in the definition of "addiction" that we choose to adopt, and this is by no means a trivial matter. Originally, addiction was a term coined to describe a psychological disorder (Freud himself refers to compulsive masturbation as the primary addiction in his writings). Granted, in those days modern neuroscience did not yet exist, and therefore the workings of the mind tended to be considered in isolation of brain physiology, simply because very little was known about the latter. The focus gradually shifted in the course of the twentieth century, as scientists started investigating the changes that substances of abuse provoked in patterns of neuronal firing and neurotransmitter release. This led to the description of the mesolimbic reward system: essentially a group of neurons that release dopamine into a specific brain area (the nucleus accumbens) in response to pleasurable stimuli. In fact, it was discovered that what made these stimuli pleasurable was precisely this focalized release of dopamine, and that certain drugs had the ability to stimulate this system even in their absence. Addiction was thus redefined in terms of the neurochemistry of the brain. Any substance and/or stimulus that was capable of over-stimulating the system normally responsible for our experience of pleasure was in principle potentially addictive. Notice, however, that since the great majority of us (except perhaps those with severe cases of anhedonia) experience pleasure regularly in our daily life, the difference between a normal, well-adjusted individual and an addict becomes, under this new definition, only a matter of degree. We all experience dopamine highs routinely, but the addict lives for them.

Since drugs of abuse were only "hijacking" our internal pleasure system, there was no longer any need to restrict the list of stimuli capable of becoming addictive. Why not include also behavioral patterns like eating, gambling, shopping, working, running, using electronic devices, playing videogames … or having sex? After all, sex is one of the first things that comes to mind when prompted to name a pleasurable experience. Thus, behavioral addictions began to be included in medical manuals, and terms like sex addiction were incorporated into pop culture. It is interesting to remark, however, that since most of us regularly engage in many of these activities in our daily lives, but nevertheless fail to become addicted to them, there has to be something more to it besides the dopamine rush.

There have been attempts to take this even further. In July 2005 the British newspaper The Guardian ran a piece on the research of Dr. Judith Reisman, who published an article entitled "The Psychopharmacology of Pictorial Pornography Restructuring Brain, Mind & Memory & Subverting Freedom of Speech". In it, Reisman characterizes pornography as an "erototoxin that produces an addictive drug cocktail of testosterone, oxytocin, dopamine and serotonin with a measurable organic effect on the brain." She admits that one of her objectives is to demonstrate that pornography restructures the brain of those who consume it much in the same way as drugs of abuse often act to generate dependence. This will in turn open the door to potential lawsuits against the providers of pornography, in the same line as those brought against big tobacco companies and fast food chains.

The Spectator, a weekly British magazine known for its conservative slant, ran a piece some years ago on the story of Sean Thomas, a man who confessed falling victim to "Internet porn addiction". Thomas detailed how he went from an initial attitude of indifference to an ever-increasing interest to explore complex sexual scenarios on display in pornographic sites, how this led to sleep deprivation and health deterioration, and how this ended up landing him in the ER. (At this point he decided to assume himself as an addict, only to discover later that many of his male friends also identified with this general behavioral pattern.) In a recently published book on brain plasticity, its author, Norman Doidge, writes, "The men at their computers looking at porn were uncannily like the rats in the cages of the National Institute of Health (NIH), pressing the bar to get a shot of dopamine or its equivalent. Though they didn’t know it, they had been seduced into pornographic training sessions that met all the conditions required for plastic change of brain maps. Each time they felt sexual excitement and had an orgasm when they masturbated, a spritz of dopamine, the reward neurotransmitter, consolidated the connections made in the brain during the sessions."

This kind of rhetoric brings to the table the specious issue of free will of the individual. Remarkably, the same sort of arguments can be used for two different purposes that at first appear as diametrically opposed. On the one hand, individuals themselves can use them to avoid having to take responsibility for their own behavior ("I just couldn’t help doing it, I have an addict brain"). On the other hand, they can be used to single out certain types of behavior deemed as undesirable or pernicious by a particular group, argue that they modify the neurochemistry of the brain so that individuals who engage in them regularly become addicts, and use this as an argument to justify their banishment. As Dr. Reisman put it rather bluntly in her testimony for a hearing held by the U.S. senate on the subject, "Thanks to the latest advances in neuroscience, we now know that pornographic visual images imprint and alter the brain, triggering an instant, involuntary, but lasting, biochemical memory trail, arguably, subverting the First Amendment by overriding the cognitive speech process."

The scientific basis to support such arguments is, however, very scant. On one end of the spectrum, it is widely accepted that certain substances such as opioids do indeed trigger long lasting changes in the organism of individuals who consume them regularly. This becomes evident when these individuals experience physical symptoms of withdrawal, including sweating, nausea, fatigue, vomiting, and pain. In these cases, the body of the addict has become used to the presence of the substance, and when it is not there anymore, it can no longer function properly. But beyond these clear-cut cases, defining addiction from a neurological standpoint becomes more and more difficult. Sure enough, both shooting cocaine and having an orgasm stimulate your mesolimbic system by a sudden release of dopamine, but so does scoring a goal in a soccer game, going on a rollercoaster ride, skiing, diving, dancing, or watching a movie. In fact, it may be argued that every single action that we can describe as pleasurable involves the activation of this system. But if we can potentially become addicted to anything (or anything pleasurable, at least), where exactly do we draw the line between healthy pleasure-seeking and addiction? Moreover, it goes without saying that most people regularly engage in some form of sexual activity (or in drinking or TV-watching, for that matter) without it becoming disruptive of their occupational, domestic, or social obligations. Simple stimulation of the pleasure centers in the brain cannot then be the entire explanation. Somehow those who fall victim to an addiction are unable to resist impulses to engage in a specified behavior, no matter how inconvenient this may become beyond a certain limit, whereas the non-addicted does not seem to have a problem overruling these impulses when the circumstances call for it.

Whether this reflects an underlying difference in the way the brain works is still hotly debated between scientists working in the field of addiction, and no clear consensus has been reached yet. The same goes for the origin of these differences, in case they happen to exist at all. Are they genetic? Do they reflect exposure to a particular environment during early life? And if so, which kinds of stimuli are likely to lead to the development of a personality prone to become addicted, and when do they have their effect? Given that the actual number of research groups around the world that are currently looking to find answers to these questions is enormous, we may expect to have a much clearer picture of addiction as a biological phenomenon a few decades, or even a few years, down the road. In the meantime, it is important to bear in mind that scientific explanations are often used to legitimize arguments from those who have social control as their hidden agenda.


Cristian Bodo was born in Buenos Aires, Argentina. For his Ph.D. in neuroscience from the University of Virginia, he studied the role of gonadal steroids in the sexual differentiation of reproductive behavior. He is currently conducting postdoctoral research at King's College London, in the field of learning and memory.