Background: This double-blind, placebo-controlled, flexible-dose study was conducted to investigate the efficacy and tolerability of the controlled-release (CR) formulation of paroxetine in adults with social anxiety disorder.
Method: Outpatients with a primary diagnosis of social anxiety disorder according to DSM-IV criteria entered a 1-week, single-blind, placebo run-in period. Eligible patients were randomly assigned to receive paroxetine CR (flexible dose of 12.5-37.5 mg/day) or placebo for 12 weeks of treatment. The primary efficacy measures were the change from baseline in Liebowitz Social Anxiety Scale (LSAS) score and the proportion of responders based on Clinical Global Impressions (CGI)-Global Improvement scale score. Data were gathered from September 2001 to July 2002.
Results: The intent-to-treat population consisted of 186 patients randomly assigned to paroxetine CR and 184 patients randomly assigned to placebo. Statistically significant differences in favor of paroxetine CR compared with placebo were observed in the change from baseline to week 12 last-observation-carried-forward (LOCF) dataset in LSAS total score (difference = -13.33, 95% confidence interval [CI] = -18.25 to -8.41, p <.001). In the CGI-Global Improvement responder analysis, 57.0% of patients treated with paroxetine CR achieved response (very much improved or much improved), compared with 30.4% of patients treated with placebo at week 12 LOCF (odds ratio = 3.12, 95% CI = 2.01 to 4.83, p <.001). Dropout rates due to adverse events were low and comparable in both treatment groups.
Conclusion: Paroxetine CR effectively treated the symptoms associated with social anxiety disorder and was well tolerated, with few patients stopping treatment due to adverse events. This favorable tolerability profile may enable more patients to experience the benefits of effective therapy.