Investigators examined whether premenstrual dysphoric disorder (PMDD) poses a risk for major depressive disorder (MDD). In an initial study, women rated premenstrual symptoms and functional impairment daily for two menstrual cycles. A semistructured diagnostic interview was given to obtain psychiatric histories and differentiate PMDD from premenstrual exacerbations of other disorders. Participants in this pilot study were eight women with PMDD and a random subgroup without PMDD (n = 9) initially. Another semistructured interview was given to diagnose psychiatric disorders occurring during a two-year follow-up interval. In all, seven of the eight women with PMDD developed MDD within two years, including all those who had never had MDD before. The odds that a woman with PMDD developed MDD were 14 times the odds that a woman without PMDD developed MDD ( p