The diagnosis, epidemiology, etiology, and treatment of premenstrual syndrome are reviewed. A relationship between depression and premenstrual syndrome is suggested by the increased prevalence of prior depressive episodes in women with premenstrual syndrome, common neurotransmitter and chronobiologic abnormalities, and the successful treatment of premenstrual syndrome with regimens used for depression. The relationship between menopause and depression is not clearly defined, but the perimenopausal years may be a time of increased depression for women who are at risk for depressive recurrences. The role of hormone replacement treatments in either ameliorating or promoting depression in menopausal women is a subject for future studies.