Abstract
BACKGROUND: Childhood obesity and mental health disorders are increasingly prevalent. While lifestyle interventions are widely recognized as effective for managing obesity in children and adolescents, their effects on mental health remain unclear. This study aimed to systematically evaluate the effects of lifestyle interventions on mental health outcomes among children and adolescents with overweight or obesity. METHODS: In this systematic review and meta-analysis, we searched five databases (PubMed, Embase, MEDLINE, CENTRAL and CINAHL) for relevant randomised controlled trials (RCTs) or non-randomised studies of interventions (NRSIs) published from database inception to December 7, 2024, without language restrictions. Lifestyle interventions are defined as structured programs that promote health-related behavioural changes across diverse domains, such as physical activity, dietary adjustments, cognitive training, and psychosocial support. We included studies that assessed the effects of lifestyle interventions on mental health outcomes among children and adolescents with overweight or obesity. Two reviewers independently screened records for eligibility, extracted study-level data and assessed risk of bias of RCTs and NRSIs via the revised Cochrane Risk of Bias Tool for randomised controlled trials (RoB 2) and the Risk of Bias in Non-randomised Studies-of Interventions (ROBINS-I), and certainty of the evidence by the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach. RCTs were prioritized as the primary source of evidence, while NRSIs served as supplementary evidence. A random-effects meta-analysis model was performed to calculate pooled standardized mean differences (SMDs) and 95% confidence intervals (CIs). Subgroup analyses stratified by age, body mass index (BMI) category, intervention type, theoretical framework, duration, and World Bank income region, were further conducted to identify potential sources of heterogeneity. The review protocol was registered in PROSPERO, CRD42024571061. FINDINGS: We identified 20,359 records, of which 26 studies (17 RCTs and nine NRSIs) involving 3511 children and adolescents with overweight or obesity were included. Mental health outcomes assessed included depression, anxiety, self-concept, self-efficacy, negative affect, quality of life, and emotional functioning. Lifestyle interventions evaluated encompassed physical activity, health education, emotion regulation, diet, and multicomponent approaches. Among RCTs, reductions in depression (SMD = -0.24, 95% CI: -0.39 to -0.10, I-square [I (2)] = 0.0%) and improvements in quality of life (SMD = 0.24, 95% CI: 0.04-0.44, I (2) = 44.0%) were observed, with moderate certainty. Subgroup analyses revealed greater reductions in depression among adolescents and participants with obesity, in programs that involving multicomponent approaches, lasting below three months, using behavioural and cognitive theory, or being conducted in high-income countries (HICs). For quality of life, greater improvements were observed among participants with overweight or obesity, in programs based on behavioural and cognitive theory, or in those conducted in low- and middle-income countries (LMICs). Meanwhile, among NRSIs, reductions in depression (SMD = -0.22, 95% CI: -0.33 to -0.11, I (2) = 11.5%), as well as enhancements in self-concept (SMD = 0.19, 95% CI: 0.09-0.29, I (2) = 0.0%), quality of life (SMD = 0.52, 95% CI: 0.23-0.81, I (2) = 86.2%), and emotional functioning (SMD = 0.40, 95% CI: 0.21-0.60, I (2) = 0.0%) were noted. However, the effects on other mental health outcomes, including anxiety, negative affect, and self-efficacy, remain inconclusive. INTERPRETATION: Lifestyle interventions modestly improve depressive symptoms and quality of life in children and adolescents with overweight or obesity, with additional benefits for self-concept and emotional functioning observed in NRSIs. These findings underscore the potential of lifestyle interventions to address both physical and mental health. Future research should focus on evaluating long-term psychological outcomes and developing cost-effective, culturally tailored interventions. FUNDING: This study was supported by National Natural Science Foundation of China (72474196).