Chapter 8 What are the Effects of Antipsychotics on Sexual Dysfunctions and Endocrine Functioning? Authors: Rikus Knegtering, M.D., Andrea van der Moolen, B.A., Stynke Castelein, M.Sc., Herman Kluiter, M.Sc., Ph.D., Rob van den Bosch, M.D., Ph.D. Affiliation of the authors: University Hospital Groningen, Department of Psychiatry, The Netherlands Psychoneuroendocrinology 2003, Vol 28S2 pp 109-123 Summary The literature is reviewed and preliminary results of new studies are presented showing that treatment with classical antipsychotics, as well as risperidone, induces sexual dysfunctions in 30% to 60% of the patients. These antipsychotics also frequently induce amenorrhoea and galactorrhoea. Although comparative studies are rare, it is likely that prolactin-sparing antipsychotics, as recently shown in a randomized trial of olanzapine versus risperidone, induce less sexual side effects. From these studies, it becomes apparent that prolactin elevation induced by classical antipsychotics and risperidone is probably a factor in inducing sexual dysfunctions, amenorrhoea and galactorrhoea. The role of other factors inducing sexual dysfunctions like sedation, ∝-blockade, testosterone, dopamine, and serotonin is discussed. Finally, it is concluded that sexual and hormonal effects of antipsychotics, although clearly important, are often neglected, in research as in clinical practice. Lowering the dosage or switching to a prolactin-sparing antipsychotic often reduces sexual side effects, amenorrhoea, and galactorrhoea. 101