Objective
Cognitive-behavioral therapy (CBT) is a first-line treatment for anxiety and depressive disorders, but its preventive efficacy remains uncertain. This study systematically reviewed and meta-analyzed randomized controlled trials of universal CBT-based interventions across all age groups, evaluating their effects on anxiety, depression, and quality of life.

Methods
We included randomized controlled trials of universal CBT programs delivered to general populations without prior risk or symptom screening. Eligible outcomes were depressive and anxiety symptoms and quality of life. Risk of bias was assessed using the Cochrane Risk of Bias tool. Separate three-level meta-analyses were conducted for each outcome, and subgroup analyses were performed by participant age and provider profession.

Results
Seventeen RCTs (n = 10,809 participants) met inclusion criteria. Pooled effect sizes were SMD = –0.02 (95% CI: –0.12 to 0.09) for quality of life, SMD = –0.09 (95% CI: –0.20 to 0.01) for depressive symptoms, and SMD = –0.03 (95% CI: –0.18 to 0.13) for anxiety symptoms. None reached statistical significance. Subgroup analyses confirmed no significant effects in children/adolescents or adults. Interventions delivered by psychologists were more effective than those delivered by teachers (SMD = 0.18), although overall preventive effects remained negligible.

Conclusions
Universal CBT interventions did not demonstrate significant preventive benefits for anxiety, depression, or quality of life across age groups. These findings suggest that universal CBT should not be adopted as a population-wide prevention strategy, and future research should prioritize targeted, data-driven approaches.