Double-blind placebo crossover study of cyproterone acetate in the treatment of the paraphilias.

Cyproterone acetate is a powerful antiandrogen used in the treatment of the paraphilias for at least a decade. Studies have reported it effective in reducing the recidivism rates of sexual crimes perpetrated by men. It acts through competitive inhibition of the androgen receptors blocking the effects of testosterone and dihydrotestosterone. Systematic clinical study of its effectiveness and its clinical effects on sexual behavior is lacking, however. In the current study 19 paraphilic men who had also recidivated in a variety of sexual crimes were treated with cyproterone acetate and placebo in a double-blind crossover design. The use of active drug was associated with a significant reduction of some aspects of sexual behavior, particularly sexual fantasies. There were also significant effects on levels of circulating sex hormones and some effects on physiological measurements and self-reports of sexual arousal.