Barriers to and Facilitators of Implementation of Internet-Delivered Therapist-Guided Therapy in Child and Adolescent Mental Health Services: Systematic Review and Bayesian Meta-Analysis

Abstract BackgroundInternet-delivered therapist-guided therapy (e-therapy) represents a promising approach for enhancing accessibility, treatment fidelity, and scalability within child and adolescent mental health services (CAMHS). ObjectiveThis systematic review aimed to (1) identify and synthesize determinants of implementation, specifically barriers to and facilitators of e-therapy in CAMHS structured according to the Consolidated Framework of Implementation Research (CFIR); and (2) provide pooled benchmark estimates of key implementation outcomes for fidelity, cost-effectiveness, and acceptability. MethodsA PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses)–compliant systematic review was performed across PsycINFO, MEDLINE, Web of Science, CINAHL, Embase, Cochrane, and ProQuest Dissertations & Thesis on June 6, 2025—to identify peer-reviewed studies assessing implementation outcomes or determinants of e-therapy in the context of outpatient CAMHS (ages 8‐18 years). Barriers and facilitators were synthesized qualitatively with thematic analysis applying CFIR. A parallel quantitative synthesis of Proctor et al’s taxonomy of implementation outcomes was performed using Bayesian multilevel random-effects meta-analyses to estimate pooled effect sizes and 95% credible intervals (CIs). By combining quantitative benchmarks of implementation success with qualitative insights into contextual determinants, the review provides an integrated understanding of what drives effective e-therapy implementation in CAMHS. Study quality was assessed using the CASP (Critical Appraisal Skills Programme) checklist, Cochrane Risk of Bias tool, and Risk Of Bias In Non-randomized Studies–of Interventions tool. Small study effects were evaluated using funnel plots, sensitivity analyses, and the Egger test. ResultsFrom 50,026 screened reports, 50 studies published between 2007 and 2025 were included: 18 randomized controlled trials, 17 cohort, and 15 qualitative or mixed methods studies. Most studies originated from Western Europe (n=34), Northern America (n=11), and Oceania (n=5), targeting anxiety (n=24) and depression (n=9), through cognitive behavioral therapy–based programs (n=47), with parallel parent content (n=31). Therapist guidance was primarily asynchronous (n=43). Among the 39 studies reporting determinants, common barriers and facilitators were identified across intervention, organization, therapist, and patient domains, structured via CFIR. Pooled implementation outcomes showed modest dropout rates (~20%, CI 14%‐27%), high module completion (~68%, CI 60%‐75%), low therapist time (24 min per wk per patient, 95% CI 19‐28), and high patient satisfaction (24/32 on Client Satisfaction Questionnaire-8, 95% CI 22‐27; and 76% satisfaction rate, 95% CI 62%‐87%), suggesting e-therapy is resource efficient and acceptable if implemented successfully. ConclusionsThis review provided the first integrated synthesis of pooled benchmarks for implementation outcomes of e-therapy in CAMHS and modifiable determinants to inform future service planning and scale-up. These findings highlighted service-level enablers, such as leadership anchoring, targeted use, technical stability, structured patient flow, and therapist training, that organizations could prioritize to strengthen sustainable e-therapy implementation in CAMHS.