The inclusion of Premenstrual Dysphoric Disorder (PMDD) as a diagnostic category of DSM-IV has been hotly debated with controversy centering on the continued lack of empirical support for its existence. The proposed research seeks to provide evidence on whether PMDD exists and has diagnostic validity based on DSM-IV research criteria. Additional aims are to determine the prevalence of 1) PMDD co-occurring with other psychiatric disorders, 2) premenstrual exacerbations of other Axis 1 psychiatric disorders, and 3) past psychiatric disorders among women with and without a current diagnosis of PMDD. Two thousand six hundred women between the ages of 13 and 55 years will be selected by probability sampling and followed for two menstrual cycles. Half of the subjects will be drawn from the St. Louis MSA and half from the Chicago MSA. Urban and rural subsamples will be drawn from each of the two geographic areas. Subjects will be asked to complete daily symptom questionnaires and provide daily urine specimens for the period of study. The latter will be used to establish phase of cycle. Responses on the symptom questionnaire will be liked to phase of cycle so that symptom severity during the postmenstrual and premenstrual phases can be compared, as per the first DSM-IV research criteria. Symptom severity will be analyzed using the absolute severity method and the Trigg method of trend analysis. Other DSM-IV research criteria for PMDD will be addressed by following subjects for two cycles and via measures of 1) interference with functioning and 2) psychiatric diagnoses. Interference with functioning will be measured daily. Psychiatric interviews will be conducted in subjects' homes at the beginning of the study (to obtain current and lifetime diagnoses) and on a monthly basis thereafter (to assess premenstrual change in the symptoms of relevant psychiatric disorders). Rasch analysis will be used to confirm the definition of PMDD and to establish profiles of women with PMDD.