The role of testosterone in sexuality and paraphilia--a neurobiological approach. Part II: testosterone and paraphilia.

INTRODUCTION: Antiandrogen therapy has been used for 30 years to treat paraphilic patients and sexual offenders. Yet the therapeutic success of antiandrogens is uncertain. Furthermore, there is still a lack of comprehensive knowledge about the effects of androgen-lowering therapy in paraphilic patients. AIM: We discuss endocrinological, neurobiological, and therapeutic aspects of paraphilia with the aim of integrating these on the basis of the current neurobiological and clinical knowledge on testosterone that was set out in Part I of this review.
METHODS: Our review of the human literature comprises the current knowledge about the neurobiology of paraphilia and the known endocrinological, pathophysiological, and genetic aspects of this disorder. The role of testosterone is discussed. A survey of antiandrogen therapy and its outcome in paraphilic patients and sex offenders is provided.
RESULTS: Although not all data are consistent, current imaging research suggests that structural and functional changes in pedophilia appear for the most part in brain regions also involved in sexual functions. Not exclusively testosterone but also some other endocrinological and neurochemical parameters could be disturbed in pedophilic patients and child molesters; these include changes in hypothalamic-pituitary function, prolactin levels, and dopaminergic or serotonergic functions. There appears to be a sex-steroid-related genetic influence on antisocial traits, externalizing behavior, and sexual behavior. Most of the studies in which antiandrogen therapy in paraphilic patients and sex offenders have been examined were case reports, or observational or open-label studies, and many did not include adequate control groups. Only a few placebo-controlled double-blind studies have been published with inconsistent results concerning treatment effects. Outcome measures differ between the studies and do not seem ideally suited to their purpose.
CONCLUSIONS: On the basis of the current knowledge about testosterone and its effects on brain and behavior as described in Part I, and of available results on the relationship between testosterone and paraphilia as well as antiandrogen therapy, we present from a neurobiological perspective an extended scientific proposal for design features to investigate the effects of antiandrogen treatment in large clinical trials.