What Four Decades of Meta-Analysis Have Taught Us About Youth Psychotherapy and the Science of Research Synthesis.

Intervention scientists have published more than 600 randomized controlled trials (RCTs) of youth psychotherapies. Four decades of meta-analyses have been used to synthesize the RCT findings and identify scientifically and clinically significant patterns. These meta-analyses have limitations, noted herein, but they have advanced our understanding of youth psychotherapy, revealing (a) mental health problems for which our interventions are more and less successful (e.g., anxiety and depression, respectively); (b) the beneficial effects of single-session interventions, interventions delivered remotely, and interventions tested in low- and middle-income countries; (c) the association of societal sexism and racism with reduced treatment benefit in majority-girl and majority-Black groups; and, importantly, (d) the finding that average youth treatment benefit has not increased across five decades of research, suggesting that new strategies may be needed. Opportunities for the future include boosting relevance to policy and practice and using meta-analysis to identify mechanisms of change and guide personalizing of treatment.