Group cognitive behavioral therapy for patients with generalized social anxiety disorder in Japan: outcomes at 1-year follow up and outcome predictors

Background Social anxiety disorder (SAD) is one of the most common psychiatric disorders worldwide. Cognitive behavioral therapy (CBT) is an effective treatment option for patients with SAD. In the present study, we examined the efficacy of group CBT for patients with generalized SAD in Japan at 1-year follow-up and investigated predictors with regard to outcomes. Methods This study was conducted as a single-arm, naturalistic, follow-up study in a routine Japanese clinical setting. A total of 113 outpatients with generalized SAD participated in group CBT from July 2003 to August 2010 and were assessed at follow-ups for up to 1 year. Primary outcome was the total score on the Social Phobia Scale/Social Interaction Anxiety Scale (SPS/SIAS) at 1 year. Possible baseline predictors were investigated using mixed-model analyses. Results Among the 113 patients, 70 completed the assessment at the 1-year follow-up. The SPS/SIAS scores showed significant improvement throughout the follow-ups for up to 1 year. The effect sizes of SPS/SIAS at the 1-year follow-up were 0.68 (95% confidence interval 0.41–0.95)/0.76 (0.49–1.03) in the intention-to-treat group and 0.77 (0.42–1.10)/0.84 (0.49–1.18) in completers. Older age at baseline, late onset, and lower severity of SAD were significantly associated with good outcomes as a result of mixed-model analyses. Conclusions CBT for patients with generalized SAD in Japan is effective for up to 1 year after treatment. The effect sizes were as large as those in previous studies conducted in Western countries. Older age at baseline, late onset, and lower severity of SAD were predictors for a good outcome from group CBT.