The efficacy of the unified protocol for emotional disorders in children and adolescents: A systematic review and meta-analysis

• Meta-analysis examining UP-C/A included 9 RCTs, 11 uncontrolled studies, and 1 SCED • Transdiagnostic treatment reduced internalizing symptoms in youth • Emotion regulation improved, underpinning the theoretical assumptions of the UP-C/A • Gender, age and treatment format did not exert any impact on treatment outcome • Future research focussing on mechanisms of change of the UP-C/A is warranted Transdiagnostic treatments such as the Unified Protocol for Emotional Disorders for Children and Adolescents (UP-C/A; Ehrenreich-May, J., Kennedy, S.M., Sherman, J.A., Bilek, E.L., Buzzella, B.A., Bennett, S.M., Barlow, D.H., 2017a) aim to target shared mechanisms across mental disorders and to achieve positive treatment outcomes. Several studies investigated the UP-C/A with promising results regarding the improvement of internalizing symptoms. However, there is currently no meta-analysis investigating the efficacy across the existing studies. In this preregistered systematic review and meta-analysis (PROSPERO CRD42023474832), we analyzed whether the UP-C/A is effective in reducing internalizing symptoms (primary outcome) and secondary outcomes such as emotion regulation in comparison to control treatments where applicable, and from pre- to post-treatment and follow-up. We also examined whether moderators (i.e., sample and treatment characteristics) predicted the effects of the UP-C/A. We included 21 studies (9 RCTs, 11 uncontrolled studies, 1 single-case experimental study) with a total of N = 994 participants. For internalizing symptoms, we found moderate to large controlled effects post-treatment ( g = 0.58, p = .014) and at follow-up ( g = 0.79, p = .003). Uncontrolled effects were large in both cases. We also found moderate to large effects for secondary outcomes (i.e., emotion regulation, global severity of psychopathology, global functioning). Treatment format did not impact the efficacy. Overall, our findings suggest that the UP-C/A is effective in treating internalizing symptoms in children and adolescents that can be offered in different formats. However, more research is needed to draw robust conclusions regarding specific treatment mechanisms underlying these effects.