Does Sex Addiction Have Any Basis in Science?

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.