Effectiveness of an add-on guided internet-based emotion regulation training (E-TRAIN) in adolescents with depressive and/or anxiety disorders: study protocol for a multicenter randomized controlled trial

BACKGROUND: During adolescence, depressive and anxiety disorders are among the most common mental health disorders. Both disorders tend to persist, are predictive for other mental disorders, and are associated with severe impairment in diverse areas. Although Cognitive Behavioral Therapy (CBT) has proven to be an effective treatment, a considerable number of adolescents do not respond to CBT and residual symptoms often remain. Therefore, it is of great importance to improve treatment outcomes for depressed and/or anxious adolescents. Dysfunctional emotion regulation appears to be a transdiagnostic factor in the development and maintenance of aforementioned disorders. Enhancing emotion regulation skills may therefore reduce symptom severity. In light of this, we developed a guided internet-based emotion regulation training (E-TRAIN) that will be added to CBT. This study aims to evaluate the effectiveness of E-TRAIN + CBT compared to CBT alone on depressive and anxiety outcomes among adolescents with depressive and/or anxiety disorder. METHODS: In this multicenter two-arm randomized controlled trial with parallel group design, we aim to include 138 adolescents, aged 13–19 years, referred for treatment and diagnosed with depressive and/or anxiety disorder. Participants will be allocated to either CBT or CBT + E-TRAIN. Assessments will take place at baseline, and at 3 (T1), 6 (T2) and 12 (T3) months after baseline. We will conduct multi-informant assessments: the adolescent, a parent/caregiver, and the CBT therapist will be asked to fill in questionnaires. The continuous primary outcome measure is self-reported depressive and anxiety symptoms at six months after baseline, measured with the RCADS25. Secondary outcome measures include anxiety or depression diagnosis based on a semi-structured clinical interview, emotion (dys) regulation, and parent-report measures of anxiety, depression and emotion (dys) regulation. DISCUSSION: This study is the first randomized controlled trial to examine the additional value of a guided internet-based emotion regulation training to regular CBT in adolescents with depressive and/or anxiety disorders. If this intervention is effective, it can be implemented in mental health care and improve treatment for these young people. TRIAL REGISTRATION: Registered on June 23, 2021 in The Netherlands Trial Register (NL9564). Retrospectively registered. Recruitment started in May 2021 and is ongoing. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12888-022-04291-6.