A Randomized Controlled Trial of Venlafaxine Extended Release in Generalized Social Anxiety Disorder

Michael R. Liebowitz, M.D.; Richard M. Mangano, Ph.D.; Jacques Bradwejn, M.D.; and Gregory Asnis, M.D.

Background: Generalized social anxiety disorder is a debilitating psychiatric illness characterized by maladaptive thoughts about social situations. This double-blind study evaluated the anxiolytic efficacy, safety, and tolerability of venlafaxine extended release (ER) in adult outpatients with generalized social anxiety disorder.

Method: Patients were randomly assigned to receive 12 weeks of treatment with a flexible dose of venlafaxine ER (75 to 225 mg/day) or placebo. The Liebowitz Social Anxiety Scale (LSAS) total score was the primary efficacy variable. Secondary efficacy variables included scores on the Clinical Global Impressions-Severity of Illness (CGI-S) and -Improvement (CGI-I) scales, Social Phobia Inventory (SPIN), and LSAS subscales. Response was defined as a CGI-I score of 1 or 2. Two definitions of remission were used: LSAS total score <= 30 and CGI-I score of 1.

Results: Data from 271 patients (intent-to-treat population) were analyzed for efficacy; 279 patients were analyzed for safety. Overall, 173 patients completed the study. Improvement on the LSAS was significantly greater with venlafaxine ER treatment than with placebo at weeks 6 through 12 (p < .05, weeks 6 and 8; p < .01, week 10; and p < .001, week 12) and at weeks 8 through 12 based on CGI-S and SPIN scores. Week 12 response and remission (LSAS score <= 30) rates were significantly greater in the venlafaxine ER group than in the placebo group (response: 44% vs. 30%, respectively, p = .018; remission: 20% vs. 7%, respectively, p < .01). Patients experienced no unexpected or serious adverse events.

Conclusion: Venlafaxine ER is safe, well tolerated, and efficacious in the short-term treatment of generalized social anxiety disorder.

(J Clin Psychiatry 2005;66:238-247)

Received Oct. 20, 2003; accepted Nov. 8, 2004. From the New York State Psychiatric Institute, New York (Dr. Liebowitz); Wyeth Research, Collegeville, Pa. (Dr. Mangano); University of Ottawa, Ottawa, Ontario, Canada (Dr. Bradwejn); and Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, N.Y. (Dr. Asnis).

This study was supported by Wyeth Research, Collegeville, Pa.

Dr. Liebowitz has been a consultant for and received grant/research support and honoraria from Wyeth, Pfizer, and GlaxoSmithKline and has been on the speakers/advisory boards of Wyeth, Pfizer, GlaxoSmithKline, Forest, and Novartis. Dr. Mangano is an employee of and major stock shareholder in Wyeth. Dr. Bradwejn has been a consultant for Wyeth, Pfizer, and GlaxoSmithKline; has received grant/research support from Pfizer; and has been on the speakers/advisory board of GlaxoSmithKline. Dr. Asnis has received grant/research support from and been on the speakers/advisory boards of Lilly, Pfizer, and GlaxoSmithKline.

The SAD 387 Study Group investigators are listed at the end of the article.

Corresponding author and reprints: Michael R. Liebowitz, M.D., New York State Psychiatric Institute, 1031 Riverside Dr., New York, NY 10032 (e-mail: mrl1945@aol.com).