The premenstrual syndrome: selection of women for treatment trials.

Statements made at interview by 31 women presenting with the premenstrual syndrome (PMS) were compared with the moods and physical symptoms reported daily during the next 6 menstrual cycles. Diagnosis was confirmed in 21 women (premenstrual tension (PMT) present in greater than or equal to 5/6 cycles), not substantiated in two (PMT in less than or equal to 1/6 cycles) and in doubt in eight. Placebo treatment was associated with a significant over-all reduction in both the incidence and the severity of mood-related PMT, but had no clear effect on premenstrual physical symptoms; women with PMT in 5 cycles were usually placebo-resistant. Criteria are proposed for the selection of women for treatment trials based on their response to placebo.