Postpartum blues, postpartum neurotic depression and puerperal psychoses have distinct clinical features; they affect women in all social classes and in all cultures, and despite numerous studies they have not been linked definitively with any biologic or psychosocial variables. The only possible exception is puerperal psychosis, which emerges much more often in women with a personal or family history of a bipolar affective disorder than in women without, a finding that probably explains the reluctance of some researchers to recognize puerperal psychotic episodes as distinct from psychotic episodes at other times. If postpartum blues last longer than 2 weeks and are disabling they are classified as neurotic depression and warrant treatment, often requiring both psychosocial approaches and psychotropic drug therapy. Antidepressants, major tranquillizers, electroconvulsive therapy and lithium have proved effective in the treatment of postpartum psychoses, depending on the symptoms. Both lithium and diazepam have been reported to cause deleterious side effects on breast-fed infants, and as the side effects of other psychotropic drugs given to a nursing mother are imperfectly understood, bottle feeding seems prudent.