Prevention of anxiety disorders and depression by targeting excessive worry and rumination in adolescents and young adults: A randomized controlled trial.
This randomized controlled trial evaluated the efficacy of a preventive intervention for anxiety disorders and depression by targeting excessive levels of repetitive negative thinking (RNT; worry and rumination) in adolescents and young adults. Participants (N = 251, 83.7% female) showing elevated levels of RNT were randomly allocated to a 6-week cognitive-behavioral training delivered in a group, via the internet, or to a waitlist control condition. Self-report measures were collected at pre-intervention, post-intervention, 3 m and 12 m follow-up. Both versions of the preventive intervention significantly reduced RNT (d = 0.53 to 0.89), and symptom levels of anxiety and depression (d = 0.36 to 0.72). Effects were maintained until 12 m follow-up. The interventions resulted in a significantly lower 12 m prevalence rate of depression (group intervention: 15.3%, internet intervention: 14.7%) and generalized anxiety disorder (group intervention: 18.0%, internet intervention: 16.0%), compared to the waitlist (32.4% and 42.2%, respectively). Mediation analyses demonstrated that reductions in RNT mediated the effect of the interventions on the prevalence of depression and generalized anxiety disorder. Results provide evidence for the efficacy of this preventive intervention targeting RNT and support a selective prevention approach that specifically targets a known risk factor to prevent multiple disorders.