A sorrow shared is a sorrow halved? A three-arm randomized controlled trial comparing internet-based clinician-guided individual versus group treatment for social anxiety disorder

A growing body of evidence suggests that internet-based cognitive behavioural treatments (ICBT) are effective to treat social anxiety disorder (SAD). Whereas the efficacy of clinician-guided ICBT has been established, ICBT in a group format has not yet been systematically investigated. This three-arm RCT compared the efficacy of clinician-guided group ICBT (GT) with clinician guided individual ICBT (IT) and a wait-list (WL). A total of 149 individuals meeting the diagnostic criteria for SAD were randomly assigned to one of three conditions. Primary endpoints were self-report measures of SAD and diagnostic status taken at baseline, after the twelve-week intervention and at six-month follow-up. Secondary endpoints were symptoms of depression, interpersonal problems and general symptomatology. At post-treatment, both active conditions showed superior outcome regarding SAD symptoms (GT vs. WL: d = 0.84-0.74; IT vs. WL: d = 0.94-1.22). The two active conditions did not differ significantly in symptom reduction (d = 0.12-0.26, all ps > 0.63), diagnostic response rate or attrition. Treatment gains were maintained at follow-up. The group format reduced weekly therapist time per participant by 71% (IT: 17 min, GT: 5 min). Findings indicate that a clinician-guided group format is a promising approach in treating SAD