Clinical effectiveness and cost-effectiveness of Internet- vs. group-based cognitive behavior therapy for social anxiety disorder: 4-Year follow-up of a randomized trial

We conducted a 4-year follow-up study of participants who had received ICBT or CBGT for SAD within the context of a randomized controlled non-inferiority trial. The cost-effectiveness analyses were conducted taking a societal perspective. Participants in both treatment groups made large improvements from baseline to 4-year follow-up on the primary outcome measure (d = 1.34-1.48) and the 95% CI of the mean difference on the primary outcome was well within the non-inferiority margin. ICBT and CBGT were similarly cost-effective and both groups reduced their indirect costs. We conclude that ICBT for SAD yields large sustainable effects and is at least as long-term effective as CBGT. Intervention costs of both treatments are offset by net societal cost reductions in a short time.