The gonadotropin-releasing hormone (GnRH) agonists are a relatively new class of drugs that are potentially effective in treating disorders that are aggravated either by estrogen or testosterone. GnRH agonists are effective in the treatment of endometriosis, as well as other disorders, such as advanced prostrate cancer, precocious puberty and uterine leiomyomata. While the GnRH agonists reduce the extent of the endometrial lesions and the occurrence of pelvic pain associated with endometriosis, these agents are associated with physical and psychiatric side effects. The adverse effects of these agents are consistent with the physiological effects of ovarian suppression, such as vasomotor instability, vaginal dryness, and headaches. Preliminary results of a prospective, double-blind placebo-controlled study and an open label trial indicates that depressive mood symptoms increase in women treated with GnRH agonist therapy for endometriosis. Additional evidence suggest that sertraline effectively manages depressive mood symptoms associated with GnRH agonist therapy. The reason for the decline in mood on GnRH agonists is postulated to be associated with the decline in estrogen levels. Effective treatment strategies for depressive mood symptoms in women on GnRH agonists therapy may offer insight into the mechanisms of action of estrogen on mood.