Love is the drug, scientists find (The Telegraph)

When Roxy Music star Bryan Ferry declared that ”love is the drug” he may have been speaking the truth.

Cambridge University scientists have found that sex and drug addiction may be two sides of the same neurological coin.

When diagnosed sex addicts looked at explicit sexual images, it triggered brain activity very similar to that seen in people dependent on drugs.

But the researchers caution that this does not suggest pornography is generally addictive.

Lead scientist Dr Valerie Voon, from Cambridge University, said: ”The patients in our trial were all people who had substantial difficulties controlling their sexual behaviour and this was having significant consequences for them, affecting their lives and relationships.

”In many ways, they show similarities in their behaviour to patients with drug addictions. We wanted to see if these similarities were reflected in brain activity, too.

”There are clear differences in brain activity between patients who have compulsive sexual behaviour and healthy volunteers. These differences mirror those of drug addicts.”

Previous studies have suggested that up to one in 25 adults may be affected by an obsession with sexual thoughts, feelings or behaviour they are unable to control.

Public awareness of sex addiction has been raised by celebrities seeking help for the problem, including actors Michael Douglas and David Duchovny.

The Cambridge scientists recruited 19 male sex addicts and played them short videos featuring either explicit pornographic scenes or people engaged in exciting sports such as skiing or skydiving.

At the same time, the men’s brain activity was monitored using a functional magnetic resonance imaging (fMRI) scanner. The experiment was repeated with a matched group of volunteers not affected by sex addiction.

Three regions of the brain were found to be especially more active in the brains of the sex addicts than in the healthy volunteers, the ventral striatum, dorsal anterior cingulate and amygdala.

All three are also known to be activated in drug addicts stimulated by the sight of drug-taking paraphernalia.

The ventral striatum and anterior cingulate are involved in the processing and anticipation of rewards, while the amygdala helps establish the significance of events and emotions.

Participants were also asked to rate the level of sexual desire they felt while watching the videos, and how much they liked them.

As expected, sex addicts showed higher levels of desire when watching pornography, but did not necessarily rate the explicit videos higher in their ”liking” scores.

Younger participants exhibited more activity in the ventral striatum in response to pornographic videos, and this association was strongest in sex addicts.

Frontal control regions of the brain that act as a ”brake” on extreme behaviour continue to develop into the mid-twenties, the scientists pointed out. This may account for greater impulsivity and risk taking in young people.

Dr Voon added: ”Whilst these findings are interesting, it’s important to note, however, that they could not be used to diagnose the condition. Nor does our research necessarily provide evidence that these individuals are addicted to porn, or that porn is inherently addictive. Much more research is required to understand this relationship between compulsive sexual behaviour and drug addiction.”

Dr John Williams, head of neuroscience and mental health at the Wellcome Trust, which funded the research, said: ”Compulsive behaviours, including watching porn to excess, overeating and gambling, are increasingly common.

”This study takes us a step further to finding out why we carry on repeating behaviours that we know are potentially damaging to us. Whether we are tackling sex addiction, substance abuse or eating disorders, knowing how best, and when, to intervene in order to break the cycle is an important goal of this research.”

The findings appear in the online journal Public Library of Science ONE.