Diagnosis of premenstrual syndrome by a simple, prospective, and reliable instrument: the calendar of premenstrual experiences.

To establish a quantitative method for the diagnosis of premenstrual syndrome (PMS), a simple prospective inventory, the calendar of premenstrual experiences, was constructed. The validity and reliability of this instrument were assessed by administering it throughout two consecutive ovulatory cycles to 36 rigidly screened women with PMS and to 18 controls. To establish concurrent validity, scores on behavioral items were correlated with simultaneously obtained scores on lengthier, well-validated psychiatric inventories designed to measure depression rather than PMS, the Beck Depression Inventory and the Profile of Mood States. The results showed that the calendar of premenstrual experiences luteal phase score distinguished PMS women from controls correctly in 104 of 108 cycles, with a 2.8% false-negative rate and no false positives when used for two consecutive cycles. An upper limit follicular phase score was observed beneath which all PMS and normal control subjects fell, suggesting that a higher score is not consistent with PMS. Correlation coefficients of calendar item scores with Profile of Mood States scale scores were 0.58 for tension, 0.51 for depression, 0.46 for anger, 0.61 for fatigue, and 0.57 for confusion (P less than .0001 for all correlations). The correlation of the calendar depression item with the Beck Depression Inventory score was 0.56 (P less than .0001). The test-retest reliability of the calendar given in the same phase of two consecutive menstrual cycles was high (r = 0.78, P less than .0001). We conclude that this instrument is a valid, reliable, and practical PMS inventory, applicable to clinical and some research settings.