Follow-up effects of mindfulness-based interventions on anxiety in adolescents: a systematic review and meta-analysis of randomized controlled trials

Anxiety is one of the most prevalent mental health problems in adolescence, and its onset often coincides with the secondary school years. Mindfulness-based interventions (MBIs) have shown short-term benefits for reducing anxiety in young people, but the durability of these benefits after treatment remains uncertain. To inform clinical and school-based practice, a quantitative synthesis focused specifically on follow-up effects is needed. We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) evaluating MBIs in adolescents aged 10–19 years and reporting anxiety outcomes at follow-up assessments conducted at least 3 months after the intervention. The review followed PRISMA 2020 guidelines and was prospectively registered in PROSPERO (CRD420251234254). Major databases (PubMed, Embase, Web of Science, Cochrane Library, Scopus and CNKI) were searched from inception to November 2025. Two reviewers independently screened studies, extracted data and assessed risk of bias using the Cochrane RoB 2 tool. Standardized mean differences (SMDs; Hedges’ g) with 95% confidence intervals (CIs) were calculated under a random-effects model. Pre-specified subgroup analyses were conducted by age group (10–14 vs. 15–19 years), intervention type (MBSR/MBCT vs. mindfulness-based stress prevention, MBSP), and follow-up interval (3–6 vs. ≥6 months). Univariable meta-regression explored the impact of mean age and total intervention duration on effect sizes. Certainty of evidence for key outcomes was rated using GRADE. Eleven randomized controlled trials ( n = 9,856 adolescents) were included. Overall, MBIs were associated with a modest reduction in anxiety symptoms at follow-up assessments ≥ 3 months after treatment (SMD = − 0.30, 95% CI − 0.44 to − 0.16; I² = 79%). Subgroup analyses indicated a moderate effect at 3–6 months (SMD = − 0.40, 95% CI − 0.56 to − 0.25; I² = 52%) but a very small effect at ≥ 6 months (SMD = − 0.09, 95% CI − 0.14 to − 0.05; I² = 0%), with a significant difference between subgroups ( p < 0.001). MBIs may confer a modest follow-up benefit on adolescent anxiety, driven mainly by outcomes measured at 3–6 months. Evidence at ≥ 6 months is limited and of low certainty, and does not support a firm conclusion regarding maintenance of effects. Future trials should test whether maintenance-focused components, such as booster sessions or ongoing practice support, improve durability.