Internet-based emotion-regulation training added to CBT in adolescents with depressive and anxiety disorders: A pilot randomized controlled trial to examine feasibility, acceptability, and preliminary effectiveness.

Background: Dysfunctional emotion regulation (ER) is associated with symptoms of depression and anxiety in adolescents. This pilot study aimed to examine the acceptability and feasibility of a guided internet-based emotion regulation training (ERT) added to cognitive behavioral therapy (CBT). Furthermore, we aimed to examine the feasibility of the randomized study design and to provide a first estimate of the effectiveness of CBT + ERT compared with CBT alone in adolescents with depressive or anxiety disorders. Methods: In a pilot randomized controlled trial (RCT) with a parallel group design, 39 patients (13-18 years) with depressive or anxiety disorder were assigned to CBT + ERT ( Results: Adherence to ERT was 66.5 %, and treatment satisfaction was adequate. 76.5 % of eligible patients participated in the study. Linear mixed-model analyses showed significantly reduced anxiety symptoms ( Limitations: The sample size was small, and results regarding effectiveness remain preliminary. Data-collection took place during COVID-19, which may have influenced the results. Conclusions: Both the intervention and the study design were found to be feasible. In a larger RCT, however, improvement of recruitment strategy is necessary. Preliminary results indicate potential effectiveness in decreasing anxiety, depression, and emotion dysregulation in adolescents. The next step should be the development of an improved internet-based ERT and its evaluation in a larger RCT. Trial registration: Registered on January 14th, 2020 in The Netherlands Trial Register (NL8304).