Clinical, demographic and theory-derived maintaining factors as moderators of treatment outcome in internet-delivered cognitive behavioural therapy for children and adolescents with social anxiety disorder.

Internet-delivered cognitive behavioural therapy (ICBT) is an efficacious treatment for social anxiety disorder (SAD) in youth. However, we have limited knowledge about patient characteristics that may be associated with better (or worse) treatment outcome. Particularly concerning factors suggested to be involved in the maintenance of SAD (e.g., anticipatory anxiety and post-event processing). The aim of the current study was to evaluate possible predictors and moderators of the effect of ICBT in a randomised controlled trial where children and adolescents (N = 103; 10-17 years) with SAD received either ICBT or internet-delivered supportive therapy, ISUPPORT. Examined variables were pre-treatment levels of social anxiety, depression symptoms, putative maintaining factors as well as demographic variables like age and gender. Latent growth curve models were used to examine predictors and moderators of changes in youth and clinician rated social anxiety symptoms, from pre-treatment to 3-month follow-up. Baseline depression symptoms moderated the outcome, with higher depression scores being associated with greater reduction of SAD symptoms in ICBT compared to ISUPPORT. More difficulties at baseline with anticipatory anxiety, post-event processing, focus of attention and safety behaviours predicted greater reduction of SAD symptoms, regardless of treatment condition. No other clinical or demographic variable predicted or moderated the outcome. In summary, baseline depression severity may be an important moderator of ICBT, but the preliminary finding needs replication in sufficiently powered trials.