Venlafaxine versus clomipramine in the treatment of obsessive-compulsive disorder: A preliminary single-blind, 12-week, controlled study

Background: The objective of this study was to investigate, in a single-blind manner over a period of 12 weeks, the efficacy and tolerability of venlafaxine versus clomipramine in the treatment of obsessive-compulsive disorder (OCD). Method: Patients with a DSM-IV diagnosis of OCD and a Yale-Brown Obsessive Compulsive Scale (YBOCS) score greater than or equal to 16 were randomly assigned to receive venlafaxine, 225 to 350 mg/day (26 patients), or clomipramine, 150 to 225 mg/day (47 patients), for 12 weeks, with dosage adjustments according to tolerability and response to treatment. All patients were medication-free from at least 2 months prior to study enrollment. Efficacy measures were the YBOCS and the Clinical Global Impressions, scale (CGI), which were completed at baseline and every 4 weeks. We defined responders as patients who had an improvement from baseline in YBOCS score of greater than or equal to 35% and a CGI score less than or equal to 2. An investigator who was blinded to patients' current medication administered rating scales independently. Moreover, patients were instructed not to reveal their current treatment to this investigator. Results: Twenty-five patients in the venlafaxine group and 40 in the clomipramine group completed the 12-week trial. Responder rates at the end of the 12 weeks were 36% for venlafaxine (9/25) versus 50% for clomipramine (20/40) according to the visitwise analysis and 34.6% (9/26) for venlafaxine versus 42.6% (20/47) for clomipramine according to the last-observation-carried-forward analysis, with no statistically significant difference between the 2 drugs. Adverse experiences were reported by 61.5% of patients receiving venlafaxine (16/26) and by 91.5% of those receiving clomipramine (43/47). Conclusion: Our results indicate that venlafaxine might be as efficacious as clomipramine in the acute treatment of OCD, with fewer side effects.