Drug addicts' brain function similar to that of sex addicts, say scientists

A new has found that the brain activity that goes on in a sex addicts' head, is very similar to that of a drug addicts.'

Researchers from the University of Cambridge looked at brain activity in nineteen male patients affected by compulsive sexual behaviour and compared them to the same number of healthy volunteers. The patients started watching pornography at earlier ages and in higher proportions relative to the healthy volunteers.

Dr Valerie Voon from the University explained that the patients in the trial were the people who had substantial difficulties controlling their sexual behaviour and they showed similarities in their behaviour to patients with drug addictions, and they further wanted to see if the similarities were reflected in brain activity as well.

The study participants were shown a series of short videos featuring either sexually explicit content or sports whilst their brain activity was monitored using functional magnetic resonance imaging (fMRI), which uses a blood oxygen level dependent (BOLD) signal to measure brain activity.

The researchers found that three regions in particular were more active in the brains of the people with compulsive sexual behaviour compared with the healthy volunteers. Significantly, these regions namely the ventral striatum, dorsal anterior cingulate and amygdale, were regions that are also particularly activated in drug addicts when shown drug stimuli. The ventral striatum is involved in processing reward and motivation, whilst the dorsal anterior cingulate is implicated in anticipating rewards and drug craving. The amygdala is involved in processing the significance of events and emotions.

As anticipated, patients with compulsive sexual behaviour showed higher levels of desire towards the sexually explicit videos, but did not necessarily rate them higher on liking scores.

Dr Voon and colleagues also found that the younger the patient, the greater the level of activity in the ventral striatum in response to pornography.

Importantly, this association was strongest in individuals with compulsive sexual behaviour. The frontal control regions of the brain, essentially the 'brakes' on our compulsivity, continue to develop into the mid-twenties and this imbalance may account for greater impulsivity and risk taking behaviours in younger people. The age-related findings in individuals with compulsive sexual behaviours suggest that the ventral striatum may be important in developmental aspects of compulsive sexual behaviours in a similar fashion as it is in drug addictions, although direct testing of this possibility is needed.

Dr Voon said that there were clear differences in brain activity between patients who had compulsive sexual behaviour and healthy volunteers. Whilst these findings are interesting, it should be noted that they could not be used to diagnose the condition. Nor does the research necessarily provide evidence that these individuals are addicted to porn, or that porn is inherently addictive.

The study is published in the journal PLOS ONE.