Promising early results in Vanderbilt study

In partnership with The Homewood Foundation and the American Foundation for Addition Research, investigators at Vanderbilt University Medical Center have begun the initial phase of a unique five-year research project to learn more about the relationship of sexual arousal, brain chemistry and addiction, and the effectiveness of selective serotonin reuptake inhibiting (SSRI) antidepressant medications such as Prozac, Zoloft, and Paxil in treatment of sexual addiction.

"The objective of the study's first phase is to develop a Functional Magnetic Resonance Imaging (fMRI) map of the brain regions that are activated during sexual arousal in normal male volunteers as a precursor to studies in patients with sexual arousal disorders," said Vanderbilt's Peter R. Martin, M.D., the project's director. "We are very pleased to report that after a few subjects, we have demonstrated that it is indeed possible to identify these areas."

The research protocol involves placing a subject in an MRI scanner. Then, while the MRI is active, he is shown (through the use of video goggles) three one-minute film clips, each separated by a blank, blue screen. One film clip is humorous, the second is a relaxing nature scene, and the third issexually stimulating. "The technique then involves subtracting the image from the images we get during the sexually arousing scenes," explained Martin. "We also subtract the images generated during the humorous and relaxation segments, thus revealing the specific part of the brain involved during sexual arousal." Martin and his colleagues plan to randomize the order in which the clips are shown so they will able to say that, regardless of where in the cycle the subject sees the sexually arousing segment, it has the same effect. "We will also experiment with different types of arousing scenes (oral sex versus nudity, for example) to determine which are the most stimulating for each individual in terms of brain activation and penile tumescence," said Martin. "We will interview the subject after the session to see which one he reports to be most stimulating."

Researchers hope that the fMRI studies in normal volunteers and sexual addiction patients compiled through this project will serve to more accurately identify the brain systems that serve sexual functioning. These studies may also lead to increasingly detailed future investigations of patients with sexual addiction, as well as to future investigations of new agents that reduce craving and prevent relapse in patients with sexual addiction.