Brain activity was studied while the subjects were looking at pornographic pictures. The researchers responsible for this study used fMRI which uses a BOLD signal to monitor brain activity. They studied the responses of 19 male subjects who were self-admitted sexual addicts who were unable to control their sexual behavior and whose sexual behavior was causing significant problems for them. They then compared these findings with 19 other young men who were classified as being healthy and who had no problems with controlling their sexual habits.
Compared to the 19 healthy volunteers, the men afflicted with compulsive sexual behavior had started looking at pornographic pictures at a younger age and spent significantly more time looking at pornographic literature than did the healthy volunteers. In many ways, the patients resembled people who are addicted to drugs, in that they continued behaviors that were having negative impacts on their relationships and jobs. The objective of the study was to find out if their brains mirrored the same type of activity as did the brains of drug addicts.
To this end, both the healthy volunteers and the patients were shown a series of short videos. The videos were either sexually explicit in nature, or they were oriented towards sports. While these videos were being shown, their brain activity was monitored using an fMRI which uses a BOLD (blood oxygen level dependent) signal. The result was that the patients brains had significant increases in activity in three separate areas of the brain, the ventral striatum, the dorsal anterior cingulate and the amygdala, are regions that are also particularly activated in addicts when shown drug stimuli.
The ventral striatum is involved in processing rewards and motivation while the anterior cingulate is involved in anticipating rewards and therefore in drug craving. The amygdala is involved in the processing of the significance of events and emotions. The participants in the study were asked to fill out a questionnaire which asked them to rate the videos they saw as to the level of sexual desire experienced while they watched the videos and how much they liked each video.
The reason for the questionnaire was to measure the amount of desire experienced and compared that to the amount of liking. This is because drug addicts are driven to seek their drug because they perceive a need for it, but have little or no enjoyment of it. In fact, many addicts will state that they don’t use drugs because they enjoy the high any more but because they become really ill if they don’t.
The result of the questionnaire was as expected—the sex addicts rated the amount of desire experienced while watching the sexually explicit videos as being high or very high, but rated the liking of the same video as being poor or very low. This means that the experience perceived by the patients was while stimulating, not very enjoyable. The patients also experienced higher interactions within the regions of the network identified—with a greater amount of cross-talk between the three regions specified—while watching the sexually explicit rather than the sports videos.
The researchers also found a higher correlation between the age of the patients and the amount of brain activity—the younger patients had higher levels of activity in the ventral striatum in response to pornography. This association was strongest in patients with abnormal sexual activity. The frontal control regions of our brains—the brakes that control our compulsiveness—continue to develop into the mid-twenties. This imbalance may account for the greater impulsivity and risk-taking associated with young people. The age-related findings in these patients suggest that the ventral striatum may be involved in the development of compulsive sexual behavior much as it is in the development of drug addiction.
Also, a second study seems to show that people with compulsive sexual behavior are more susceptible to cues that trigger their compulsion than are healthy men. This study showed the men, who were divided between “healthy” men and sex addicts. They were given identical tasks. The first task involved looking at a series of images in pairs. These images were of naked women, furniture, and clothed women. They were then shown another series of images, some of which were familiar, and others which were not and told to choose a pair of pictures to win a specified amount of money. The researchers found that the sex addicts were more prone to choose the novel over the familiar choice for sexual images relative to neutral object images but that healthy men were more likely to choose the novel choice for neutral female images over neutral object images.
A second task involved learning to associate certain images overlaid with patterns with reward—similar to Pavlov’s dogs. The men were then given a choice between those images and novel images. This time, the addicts were more likely to pick cues associated with monetary and sexual rewards. This supports the theory that seemingly innocuous cues can trigger a sex addict to seek out sexual images.