Therapist Experience and Knowledge Acquisition in Internet-Delivered CBT for Social Anxiety Disorder: A Randomized Controlled Trial

Background: Guided internet-delivered cognitive behavior therapy (ICBT) has been tested in several trials on social anxiety disorder (SAD) with moderate to large effects. The aims of this study were threefold. First, to compare the effects of ICBT including online discussion forum with a moderated online discussion forum only. Second, to investigate if knowledge about SAD increased following treatment and third to compare the effects of inexperienced versus experienced therapists on patient outcomes. Methods: A total of 204 participants with a primary diagnosis of SAD were included and randomized to either guided ICBT or the control condition. ICBT consisted of a 9-week treatment program which was guided by either psychology students at MSc level (n=6) or by licensed psychologists with previous experience of ICBT (n=7). A knowledge test dealing with social anxiety was administered before and after treatment. Measures of social anxiety and secondary outcomes dealing with general anxiety, depression, and quality of life were administered before and after treatment. In addition, a 1-year follow-up was conducted on the treated individuals. Results: Immediately following treatment, the ICBT group showed superior outcome on the Liebowitz Social Anxiety Scale self-report version with a between group posttreatment Hedges g effect size of g=0.75. In addition, significant differences on all the secondary outcomes were observed. Gains were well maintained one year later. Knowledge, as assessed by the knowledge test, increased following treatment with little gain in the control group. Therapist experience did not result in different outcomes, but experienced therapists logged in less frequently compared to the inexperienced therapists, suggesting that they needed less time to support patients. Discussion: We conclude that guided ICBT reduce symptoms of SAD, increase knowledge about SAD and that therapist experience does not make a difference apart from the finding that experienced therapist may require less time to guide patients.