MULTICENTER, PLACEBO-CONTROLLED STUDY OF FLUOXETINE IN SEASONAL AFFECTIVE-DISORDER

Objective: The authors investigated the efficacy and safety of fluoxet ine in the treatment of winter seasonal affective disorder. Method: Si xty-eight outpatients who met the DSM-III-R criteria for recurrent maj or depressive episodes, seasonal (winter) pattern, were randomly assig ned to 5 weeks of treatment with fluoxetine, 20 mg/day (N=36), or plac ebo (N=32). The outcome measures included the 29-item modified Hamilto n Depression Rating Scale, administered by experienced clinicians, and the self-rated Beck Depression Inventory; adverse events and safety d ata were also recorded. Clinical response tuns defined as a greater th an 50% reduction in depression score between baseline and study termin ation. Results: Both groups showed significant improvement. The fluoxe tine group had lower depression scores at termination than the placebo group, but these differences did not achieve statistical significance . However, the rate of clinical response in the fluoxetine group (59%) was superior to that in the placebo group (34%). Post hoc analyses sh owed that the greatest fluoxetine responses were in the most markedly depressed patients and that overall response was greater for patients studied later in the season. Fluoxetine was well tolerated, and few su bjects dropped out because of adverse events. Conclusions: On the basi s of clinical response rate, fluoxetine appears to be an effective, we ll-tolerated treatment for seasonal affective disorder. Because the di fferences between fluoxetine and placebo in the continuous outcome mea sures did not reach statistical significance, further studies with lar ger study groups and longer treatment periods are required to conclusi vely demonstrate efficacy of fluoxetine for seasonal affective disorde r.