This paper reviews the literature on menstrual psychosis and proposes a new classification, adapting that of v. Krafft-Ebing (1902) and Jolly (1914). The world literature consists mainly of case reports; they include a few with data good enough for a statistical demonstration of the link between onset and menses. These well-documented cases include examples of pre-menstrual, catamenial, paramenstrual and mid-cycle onsets, and continuous illnesses with phasic shifts rhythmic with the menstrual cycle. In sufferers, episodes seem to be concentrated around the menarche and after childbirth. The clinical picture resembles that of puerperal psychosis, and there are at least 20 women who have suffered both psychoses at different epochs in their lives. Both seem to fall within the manic depressive rubric, so that menstruation can be another trigger of a bipolar episode. Some work suggests an association with anovulatory cycles. Cases starting before the menarche suggest a diencephalic origin.