Prevalence of menstrual cycle symptom cyclicity and premenstrual dysphoricdisorder in a random sample of women using and not using oral contraceptives

Background. The prevalence of symptom cyclicity and premenstrual dysphoric disorder in randomly recruited samples of women has not been ascertained. W e assessed this prospectively in 83 Icelandic women, aged 20-40 years, usin g and not using oral contraceptives (OCs). Methods. A check list of 57 symptoms, divided into 7 symptom groups, was us ed to assess experiences. All symptoms and summarized symptom scores within symptom groups were tested for significant change between the follicular a nd the luteal phase of each menstrual cycle. When a symptom or a summarized symptom score was higher during the luteal phase compared to the f(ollicul ar phase the cyclicity is labelled 'expected' cyclici)ty and the opposite ' unexpected' cyclicity. Results. The women charted from 1-7 menstrual cycles each, with 66 of them charting 3-4 cycles. Cyclicity was never displayed by 9.6% of participants; 80.7% displayed expected cyclicity and 72.3% unexpected cyclicity at least once. Cyclicity in somatic symptoms was most often demonstrated by partici pants. Expected and unexpected cyclicity in summary symptom scores in well- being and in psychoemotional symptoms was very similar among participants. There was not much difference in cyclicity between non OC users and OC user s. Fifty-one percent of the participants were self-defined with premenstrua l syndrome with 2%-6% of them meeting the criteria of premenstrual dysphori c disorder. Conclusions. The normalcy of cyclicity found in this study might explain th e high prevalence of premenstrual syndrome in many recall surveys. The impo rtance of prospective daily ratings for establishing symptom cyclicity in w omen cannot be over emphasized.