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David Fawcett PhD, LCSW


One of the questions that is frequently asked by individuals who struggle with compulsive sexual behavior is, “Why is it so hard to quit what I’m doing and then stay quit?” Basically, they find themselves returning to problematic sexual behaviors despite promises to themselves and others that they will not, and despite an ever-increasing stack of negative life consequences related to their sexual behavior.

The answer to this question is related primarily to the ‘plastic’ nature of the human brain. When I use the word ‘plastic’ here, what I mean is that the human brain is highly adaptive. It is malleable. It changes over time based on what we experience. This malleability is, in many respects, what separates humans from other animals. Our brains’ ability to adapt based on external inputs means that we are not entirely reliant on our instincts like most other species. Instead, our brains receive, process, and adapt to environmental factors – learning and changing along the way.

The technical term for this is neuroplasticity, and, in most respects, it is a uniquely human trait. Sharks, for example, think and behave almost exactly the same today as they did millions of years ago. Their non-plastic brains have not evolved at all. If sharks could time-travel, one of their relatives from hundreds of thousands of years ago could arrive in today’s ocean and fit right in. Because sharks today think and act exactly as they’ve done for millennia.

Human brains, on the other hand, evolve almost by the minute in response to both environment and experience. That doesn’t mean humans are not born with certain inherent traits, abilities, and behaviors, as we see with other species. We are. For instance, we inherently know that we need to breathe, and how to do so. That said, we also have the innate capacity, from moment one in our lives, to neurobiologically adapt, thereby developing new traits, abilities, and behaviors.

Stated simply, human brain structure and function are not etched in stone as occurs with most other species. Environmental impact and experience can and do change our brain’s structure and function on an almost moment to moment basis. Our brains are not static. They change over time, especially during key periods of development like infancy, early childhood, and adolescence. And also when we hit them with powerful external stimuli (like sex, drugs, and other neurobiologically intense inputs).

Sex and Neuroplasticity

So what does sexual behavior do to the brain? How do sex and neuroplasticity impact us in the short-term and the longer-term?

A simplified, step-by-step version of the answer to these questions is provided below.

  • In humans, a portion of the brain known as the nucleus accumbens controls the experience of pleasure, desire, and motivation. For simplicity’s sake, this region is sometimes referred to as the reward center or the pleasure center.
  • The reward center is activated (we feel pleasure) when we engage in naturally occurring, life-affirming stimuli such as eating, playing, learning, being sexual, helping others, etc. These activities are rewarded because they ensure, in various ways, survival of both the individual and the species.
  • This pleasure response is two-pronged, involving the release and reception of various neurochemicals—mostly dopamine but also adrenaline, serotonin, oxytocin, and a few others.
  • Some brain cells release these neurochemicals, other brain cells receive them, and both actions must occur before we experience pleasure. It’s like a lamp. It doesn’t turn on until you plug it in and complete the electrical circuit.
  • When pleasure is experienced—when the lamp is plugged in, so to speak—the reward center tells the mood, memory, and decision-making regions of the brain how much it enjoyed eating, playing, learning, being sexual, helping a friend, or whatever. This, of course, encourages us to engage in these life-sustaining activities again in the future. It creates desire and motivation and ensures our survival.

This is what Darwin would refer to as intelligent design.


Unfortunately, the reward center can be manipulated. For instance, alcohol, addictive drugs, and intensely stimulating behaviors (like porn, hookup apps, strip clubs, sex clubs, prostitutes, etc.) can be used to artificially stimulate the system, flooding the brain with unusually high levels of dopamine. And, as explained above, this enjoyment-related information is conveyed to areas of the brain dealing with mood, memory, and decision-making, creating motivation to repeat the behavior. So it’s hardly a surprise that we sometimes want to go back for more.

Unfortunately, that’s not the entire story with sex and our neuroplastic brains. And it’s not even the ugly part of the story. The ugly part is this:

  • As stated earlier, the human brain is plastic and adaptive. Because of this, it continually ‘heals itself’ in response to the inputs it receives. When the brain is repeatedly overstimulated—as occurs with the heavy use of pornography, apps, and the like—it recognizes the ongoing neurochemical imbalance and adjusts (heals) by reducing the amount of dopamine that is released and/or the number of receptors that can absorb the dopamine.
  • As the brain adjusts in this fashion, repeated sexual intensity has less of an impact, so the user must use more of it or a more intense version of it to achieve the desired reward. And then the brain adjusts yet again.
  • Despite this continual loss of the ability to experience pleasure from sexual behaviors like pornography, hookup apps, and the like, the mood, memory, and decision-making regions of the brain expect the same feeling. The desire and motivation have been learned and remain in play. Thus, the individual may feel compelled to engage in the behavior, despite the diminishment of actual in-the-moment pleasure.
  • Eventually, even the most intense sexual behaviors will no longer create the desired reward. At best, sexual intensity gets the individual back to zero. When sexual compulsivity hits this unpleasant stage, the user is ‘feeding the beast’ with no (or very little) neurochemical reward.

In this way, liking sexual intensity transforms into wanting/needing sexual intensity, and compulsivity/addiction takes over. Even though the stimulus (sexual intensity) no longer provides the pleasure it once did, the individual wants and needs to continue.


Eventually, the human brain can adjust to sexual intensity to the point where it becomes difficult to experience any pleasure at all. Basically, the brain turns down the volume to the point where all forms of pleasure, including natural rewards like eating a nice meal, being friendly, playing, learning, and feeling connected are dampened.

Over time, individuals who are compulsive with or addicted to sexual intensity find it difficult to experience pleasure through either normal or supernormal means. Often, they are unable to experience natural rewards at all, and with their compulsivity/addiction they are simply feeding the beast—using sexual behavior not to get high, but to get back to zero. This condition is known as anhedonia. Anhedonia occurs because, as stated above, when the brain ‘heals itself’ related to sexual intensity, the entire reward system is impacted; the volume is turned down on everything.

The good news for those who are compulsive with or addicted to sexual intensity is that the brain will heal itself yet again—eventually, with sobriety, returning the reward system to baseline levels. This process typically takes about a year, depending on sobriety and a variety of other factors.

Unfortunately, until the brain resets, recovering sex addicts may struggle to enjoy life, to connect, and to avoid relapse. Often, it helps such individuals to know that their inability to feel pleasure is a temporary phase of recovery and the brain is healing as fast as it can. When they know that with continued sobriety and healing they will be able to enjoy all aspects of life—even the small and simple pleasures—it makes it much easier to walk through the difficult moments they inevitably experience.