Full- or half-cycle treatment of severe premenstrual syndrome with a serotonergic antidepressant

Evidence that serotonergic antidepressants are effective for treating preme nstrual syndrome (PMS) raises the question of whether dosing only in the sy mptomatic premenstrual phase is effective for this disorder. This prelimina ry randomized, double-blind study compared the responses to half-cycle or f ull-cycle dosing of sertraline in 31 patients who completed a preceding dou ble-blind, short-term treatment trial. The subjects fulfilled criteria for severe PMS when they entered the preceding controlled trial. At the end of the shortterm treatment trial, the double-blind was not broken; both improv ed and unimproved subjects were randomized in a double-blind fashion to rec eive either full-cycle or half-cycle sertraline in the 3-month extension st udy. Results showed that the total premenstrual scores from the Penn Daily Symptom Report (DSR) were lower in the half-cycle dosing group in each of t he 3 treatment months but did not differ with statistical significance from the full-cycle dosing group. Further analysis of the 17 DSR items showed t hat mood swings, nervous tension, feeling out of control, and confusion wer e significantly lower (p < 0.05) at endpoint in the half-cycle dosing group . Overall, subjects who improved in prior treatment remained improved; appr oximately half the subjects who were unimproved at entry into the extension study improved, regardless of the dosing regimen. The results add support to other preliminary reports of efficacy of serotonergic antidepressants ad ministered premenstrually and indicate the clinical importance of determini ng an optimal dose/benefit ratio of serotonergic antidepressants for PMS pa tients.