The primary goal of the present study is to identify the mediators and moderators of change in the treatment of social phobia and, in so doing suggest a common mechanism of action for all brief psychosocial interventions. Perceived self-efficacy of social behavior, negative cognitive appraisal (estimated social costs), and perceived emotional control will be considered as potential mediators; avoidant personality disorder and the generalized subtype of social phobia will be considered as potential predictors for poor treatment outcome.