The goals of this project are to detect and accurately describe menstrually-related mood disorders, explore their pathophysiology and response to pharmacological and environmental manipulation, and to document the relationship between reproductive endocrine change and disorders of mood as a way of further investigating the neurobiology of psychiatric illness. In the past year we have identified: 1) the ability of GnRH analogue (Lupron) to eliminate premenstrual syndrome during the second month of administration in some but not all patients; 2) the ability of progesterone to precipitate depression in 40% of women while on Lupron; 3) a significant decrease in mononuclear cell magnesium content and concentration as well as red blood cell magnesium in PMS patients compared with controls; 4) preliminary evidence of the efficacy of an infusion of magnesium during the luteal phase in premenstrual syndrome; 5) the therapeutic efficacy of fluoxetine in five of ten women with PMS; 6) the dissociation of the switch out of PMS from menses in two of four women with artificially prolonged luteal phases.