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 >/= 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 >/= 35% and a CGI score </= 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.