The effects of cyproterone acetate on sleeping and waking penile erections in pedophiles: possible implications for treatment.

This study reports the short term effects in five pedophiles of the antiandrogenic drug cyproterone acetate (CPA) on nocturnal penile tumescence (NPT); penile responses to erotic stimuli in the laboratory; and sex hormones (testosterone, LH, FSH and prolactin). During the administration of CPA, NPT, laboratory arousal and hormone measures (except prolactin) all decreased. Waking laboratory measures were influenced less and were more variable (one subject showed greater arousal) than NPT measures. The changes in NPT closely paralleled the reduction in testosterone. The results are discussed with reference to the known psycho-neuroendocrinology of sleeping and waking erections.