Does an app designed to reduce repetitive negative thinking decrease depression and anxiety in young people? (RETHINK): a randomized controlled prevention trial

BACKGROUND: The first onset of common mental health disorders, such as mood and anxiety disorders, mostly lies in adolescence or young adulthood. Hence, effective and scalable prevention programs for this age group are urgently needed. Interventions focusing on repetitive negative thinking (RNT) appear especially promising as RNT is an important transdiagnostic process involved in the development of depression and anxiety disorders. First clinical trials indeed show positive effects of preventative interventions targeting RNT on adult as well as adolescent mental health. Self-help interventions that can be delivered via a mobile phone app may have the advantage of being highly scalable, thus facilitating prevention on a large scale. This trial aims to investigate whether an app-based RNT-focused intervention can reduce depressive and anxiety symptoms in young people at risk for mental health disorders. METHODS: The trial will be conducted in a sample (planned N = 351) of individuals aged 16–22 years with elevated levels of RNT but no current depression or anxiety disorder. In a randomized controlled between-subjects design, two versions of the app-based self-help intervention will be compared to a waiting list control condition. The full RNT-focused intervention encompasses a variety of RNT-reducing strategies, whereas the concreteness training intervention focuses on only one of these strategies, i.e., concrete thinking. The primary outcome (depressive symptoms) and secondary outcomes (anxiety symptoms and RNT) will be measured at pre-intervention, post-intervention (6 weeks after pre-intervention), and follow-up (18 weeks after pre-intervention). DISCUSSION: This trial aims to find out whether targeting RNT via an app is an effective and feasible way of preventing depression and anxiety disorders in adolescents. Since app-based interventions are highly scalable, this trial might contribute to tackling challenges related to the increasing rates of mental health disorders among young people. TRIAL REGISTRATION: https://www.drks.de, DRKS00027384. Registered on 21 February 2022—prospectively registered. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13063-023-07295-z.