Controversy has developed about the existence of a relatively discrete condition of severe premenstrual dysphoric changes in the absence of underlying mental disorder (late luteal phase dysphoric disorder). With careful screening and evaluation, women with this disorder can be identified. In this study, women who sought treatment for premenstrual syndrome were divided into two groups: individuals who experienced mood and behavior changes and impaired social functioning that were limited to the premenstrual period (n = 86), and women with persistent mental disorders who experienced exacerbation or complication of symptoms during the premenstrual period (n = 54). These groups were compared with a control group of women who had no significant premenstrual changes and no current mental disorder (n = 61). Most of the differences between subjects seeking treatment and controls that were not attributable to premenstrual changes were accounted for by the women with persistent mental disorders.