Effectiveness of an Internet-Based Self-Help Intervention versus Public Mental Health Advice to Reduce Worry during the COVID-19 Pandemic: A Pragmatic, Parallel-Group, Randomized Controlled Trial

The mental health burden for the general population due to the COVID-19 pandemic has been highlighted. Evidence on effective, easily accessible public health interventions to reduce worry, a major transdiagnostic risk-factor for, e.g., anxiety and depression, is scarce.In a pragmatic randomized controlled trial, we aimed to assess whether an internet cognitive-behavioral self-help intervention could reduce worry more than public mental health advice in the general population.Eligible internet users above the age of 18 were recruited from the German general population and randomly assigned, to either get.calm-move.on (GCMO), a 10-day unguided, internet-based self-help intervention, or mental health advice waiting group (MHA-W, receiving officially endorsed mental health recommendations). The primary outcome was level of worry, using the Penn State Worry Questionnaire (PSWQ), 2 weeks after randomization. Baseline assessment and 2-month and 6-month follow-ups were conducted. The trial was registered at the German Clinical Trials Registry (DRKS00021153).Between April 7, 2020 and December 11, 2020, we randomly assigned 351 individuals to receive either GCMO (n = 175) or MHA-W (n = 176). Participants receiving GCMO (PSWQ = 46.6; change -10.3) reported significantly less worrying at post-intervention (F1,219 = 12.9; p < 0.001; d = 0.38) than MHA-W controls (PSWQ = 51.6; change -5.1). Improvements were also seen on most secondary outcomes, including symptoms of anxiety and depression, general well-being, resiliency, and emotion regulation skills. Improvements made from baseline were stable until the 6-month follow-up.This internet-based self-help intervention providing cognitive-behavioral techniques to cope with the threatening pandemic situation is effective in reducing worry in the general population and should complement existing and potentially effective mental health recommendations.