Universal interventions to improve young children's mental well-being: A systematic review and meta-analysis

This meta-analytic review quantified the effects of universal interventions, those implemented with all children, on improving mental well-being in young children aged 0-6 years old. Potential factors that moderated the effects of interventions were explored. A systematic search of PubMed, Cumulative Index to Nursing and Allied Health Literature (Elton B. Stephens Company), APA PsycInfo (ProQuest), and grey literature identified 21,942 records. After screening, 134 articles reporting 133 studies and 141 interventions among 32,512 participants met eligibility criteria. Meta-analyses were conducted, using random-effects models and cluster-robust variance estimation to account for within-study dependence and to compute pooled Hedges' g. Mean effects at postintervention were small-to-medium on overall mental well-being (g = 0.35) across cognitive (g = 0.35), social (g = 0.36), emotional (g = 0.38), and behavioral (g = 0.31) domains. Sensitivity analyses (e.g., excluding high-risk and low-reliability studies) produced similar results. Follow-up effects adjusted for baseline were 0.22, and the maintenance of effects from postintervention to follow-up was only 0.04. Exploratory moderator analyses revealed three significant moderators, including study design, control group, and intervention target. Child-focused interventions yielded the largest effects, exceeding those targeting family and child, the occupational role (e.g., teachers), or family member only. Though these results support some promises of universal interventions for enhancing early mental well-being, interpretation warrants caution. Between-study heterogeneity was substantial, some studies exhibited a high risk of bias, and publication bias was present. Future research should prioritize rigorous designs with follow-up assessments and booster strategies to support maintenance and include implementation-relevant outcomes (e.g., fidelity), while adhering to transparent reporting. (PsycInfo Database Record (c) 2026 APA, all rights reserved).