Worry and rumination as a transdiagnostic target in young people: A co-produced systematic review and meta-analysis.

Repetitive Negative Thinking (RNT) encompasses both worry and rumination and is a transdiagnostic process. A systematic review and meta-analysis were co-produced with individuals with lived experience of anxiety and depression. The objective was to examine the efficacy of RNT-specific psychological interventions. Inclusion criteria were mean age or range 10-24 years, and including a measure of worry, rumination, RNT, anxiety, depression, psychosis, self-harm, or suicide. The Cochrane Risk of Bias measure was used. PsycInfo, Medline/PubMed, Scopus and Embase databases were searched on 24 April 2023. There were 16 studies with 20 RNT interventions, N = 1,183 participants, 79% female, mean pooled age = 20.08 years. There was a small effect of RNT interventions on anxiety symptoms (g = -0.43 to -0.47, 95% CI = -0.23 to -0.70). There were small to medium effects on depressive symptoms (g = -0.40 to -0.52, 95% CI = -0.19 to -0.84), and RNT (g = -0.59 to -0.71, 95% CI = -0.41 to -1.01). Most studies indicated some concerns for risk of bias. Transdiagnostic interventions that target RNT are efficacious in reducing symptoms of anxiety, depression, and RNT in young people. Further research is required to address younger age groups, psychosis, and different cultural contexts.