Serotonin, sex, and psychiatric illness

Numerous examples in medicine illustrate that different rates of illness between men and women (based on biologic differences) usually reflect important aspects of the underlying pathophysiology. This can be important for psychiatry, since several psychiatric illnesses have large sex differences in incidence rates. However, after nearly half a century of increasingly sophisticated research on the biologic basis of these illnesses, we still do not have a clear picture of the specific biochemical events that lead to symptom formation in patients. The paper by Nishizawa et al. (2), in the current issue of the Proceedings, reporting a reduced serotonin [5-hydroxytryptamine (5-HT)] synthesis rate in women compared with men, now provides an opportunity to investigate the role of this important neurobiologic system in those psychiatric conditions differentially affecting males and females.