A Placebo-Controlled Trial of Phenelzine, Cognitive Behavioral Group Therapy, and Their Combination for Social Anxiety Disorder

Context: Medication and cognitive behavioral treatment are the best-established treatments for social anxiety disorder, yet many individuals remain symptomatic after treatment. Objective: To determine whether combined medication and cognitive behavioral treatment is superior to either monotherapy or pill placebo. Design: Randomized, double-blind, placebo-controlled trial. Setting: Research clinics at Columbia University and Temple University. Participants: One hundred twenty-eight individuals with a primary DSM-IV diagnosis of social anxiety disorder. Interventions: Cognitive behavioral group therapy (CBGT), phenelzine sulfate, pill placebo, and combined CBGT plus phenelzine. Main Outcome Measures: Liebowitz Social Anxiety Scale and Clinical Global Impression (CGI) scale scores at weeks 12 and 24. Results: Linear mixed-effects models showed a specific order of effects, with steepest reductions in Liebowitz Social Anxiety Scale scores for the combined group, followed by the monotherapies, and the least reduction in the placebo group (Williams test = 4.97, P < .01). The CGI response rates in the intention-to-treat sample at week 12 were 9 of 27 (33.3%) (placebo), 16 of 34 (47.1%) (CBGT), 19 of 35 (54.3%) (phenelzine), and 23 of 32 (71.9%) (combined treatment) (chi(2)(1) = 8.76, P < .01). Corresponding remission rates (CGI = 1) were 2 of 27 (7.4%), 3 of 34 (8.8%), 8 of 35 (22.9%), and 15 of 32 (46.9%) (chi(2)(1) = 15.92, P < .01). At week 24, response rates were 9 of 27 (33.3%), 18 of 34 (52.9%), 17 of 35 (48.6%), and 25 of 32 (78.1%) (chi(2)(1) = 12.02, P = .001). Remission rates were 4 of 27 (14.8%), 8 of 34 (23.5%), 9 of 35 (25.7%), and 17 of 32 (53.1%) (chi(2)(1) = 10.72, P = .001). Conclusion: Combined phenelzine and CBGT treatment is superior to either treatment alone and to placebo on dimensional measures and on rates of response and remission.