The role of self-efficacy in internet-based interventions for mental health: A systematic review and meta-analysis

Introduction: Internet-based interventions (IBI) increase access to evidence-based treatments for mental disorders, but knowledge of their mechanisms of change is limited. Self-efficacy, a key factor in psychotherapy, is especially relevant in IBI due to its self-help focus. We investigated self-efficacy and related constructs as outcomes, predictors/moderators, and mediators in randomized controlled trials. Methods: A systematic search was conducted across PsycINFO, PubMed, CINAHL, and Web of Science. Two reviewers selected studies, extracted data, and assessed bias. Effects were quantified using random effect models and supplemented by narrative syntheses and box score visualizations. Results: 70 studies (N = 17,407 participants) were included. IBI showed moderate effects on self-efficacy in within (d = 0.47) and between (d = 0.46) comparisons, with guided interventions having the largest effect (d = 0.66). Findings on self-efficacy as a predictor/moderator were mixed, though some studies suggested individuals with lower self-efficacy benefit more. Self-efficacy emerged as a mediator through which IBI affected treatment outcomes. Conclusion: Self-efficacy appears influential in IBI efficacy and may itself be a valuable treatment target. However, mixed results and methodological limitations in mediator studies highlight the need for further research, particularly on long-term effects.