Recently I was asked to help a young man who had been taking Risperdal for a psychotic illness
and who noticed that while taking this his penis
and testicles seemed to shrink. There is very little information in the literature about this. We know that Risperdal causes dopamine receptor blockade. Dopamine in turn keeps prolactin levels in check. Therefore Risperdal allows for a raise in prolactin levels and this may cause genital shrinkage.