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

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.