Fluoxetine in the treatment of premenstrual syndrome.

Despite many associations between premenstrual syndrome (PMS) and major depression, there have been no placebo-controlled trials of an antidepressant in this disorder. We conducted a double-blind, randomized, placebo-controlled trial of fluoxetine in the treatment of severe PMS. The diagnosis of PMS was made using daily, prospective, self-rating forms over two menstrual cycles. Women who continued to meet criteria for PMS after a single-blind trial of placebo during one menstrual cycle were randomly assigned to treatment for two menstrual cycles with either fluoxetine at 20 mg/day (n = 9) or placebo (n = 6). Eight of the 9 subjects receiving fluoxetine responded to treatment, whereas only 1 of the 6 receiving placebo responded (p less than .025). All subjects on fluoxetine elected to continue with this treatment after completion of the study. These preliminary results suggest that fluoxetine is an effective and well-tolerated treatment for severe PMS.