Understanding Treatment Pathways in Cognitive-Behavioral and Experiential Therapies for Social Anxiety Evidence from a Randomized Controlled Trial

Background: Cognitive behavioral group therapy (CBGT), psychodrama (PD), and their integration (CBPT) are effective in treating social anxiety disorder (SAD). However, the processes underlying their effectiveness are not fully understood. This study investigated whether changes in cognitive biases and reductions in avoidance behaviours mediated treatment effects. For PD and CBPT we additionally hypothesized a mediation effect of increased spontaneity.

Methods: Using data of 116 SAD participants in a randomized controlled trial (RCT) with four conditions (waitlist, CBGT, PD, CBPT), we examined mediators of treatment effect. Mediation analyses with bootstrapping tested the pathways trough which active treatments (compared to waitlist) affected post-treatment effects.

Results: The analyses indicated that perceived cost of negative social events mediated CBGT and CBPT outcomes, while perceived probability mediated PD and CBPT. Spontaneity did not mediate effects in of any treatment, while avoidance mediated outcomes across all interventions. Analysis using post-treatment mediators were all significant and showed no treatment specificity.

Conclusions: Underscoring its critical role in treating SAD, avoidance emerged as a consistent mediator of treatment effects. In contrast, cognitive biases were treatment-specific: reduced costs mediated outcomes in interventions with cognitive techniques, while reduced likelihood mediated outcomes in experiential interventions.