A double-blind, placebo-controlled study of fluoxetine in patients with DSM-III-R obsessive-compulsive disorder. The Lilly European OCD Study Group

We have studied the effect of three fixed daily doses of fluoxetine in patients with obsessive-compulsive disorder (OCD) diagnosed according to DSM-III-R. Two hundred and fourteen patients were evaluated in an 8-week double blind, placebo-controlled study. A statistically significantly greater number of fluoxetine-treated patients achieved the prospectively defined criteria for clinical response when compared to placebo treatment. There was a statistically significant overall difference in the PGI rating of symptom change (P = 0.045) and a marginally significant difference (P = 0.089) in the CGI severity rating between groups. Pairwise comparison against placebo showed a marginally statistically significantly greater improvement (P = 0.059) in Y-BOCS-Total score for patients receiving fluoxetine 60 mg daily, and a significantly higher response rate in patients receiving fluoxetine 40 mg or 60 mg daily (P < 0.05). One hundred and sixty one patients continued to a 16-week extension evaluation. There was no significant difference in the rate of reporting of any individual adverse event between placebo and fluoxetine, and the rate of discontinuation due to adverse events was low (< 6% in each study phase). This study supports the growing evidence for the safety and efficacy of fluoxetine in the treatment of OCD.