Supplementary Material for: Investigator Meditation Practice Predicts Efficacy of Child/Adolescent Mindfulness-Based Interventions: A Meta-Analysis

Introduction: Mindfulness has been shown to benefit children and adolescents. However, predictors of treatment effects of mindfulness-based interventions (MBIs) are less well-known.

Objective: Test the treatment effect of MBIs in children/adolescents; test for moderation by meditation practice history (MPH) of the investigator(s); compare moderation by MPH to other study- and participant-level variables.

Methods: Studies were identified in PubMed and Google Scholar. English-language reports of clinical trials testing an MBI in youth were included. Investigator MPH was collected via online survey distributed to the first, last, and/or corresponding authors of included studies. Data were analyzed using random-effects models. We preformed omnibus, moderator, and multiple publication bias analyses. Treatment efficacy (Hedge’s g and r) was the primary outcome. Secondary analyses included tests for moderation by study- and participant-level characteristics, and investigator MPH.

Results: Data were included from 107 studies, including 1,393 statistics and 8,510 participants. We observed a small-to-moderate significant omnibus effect size (g = 0.33, CI: 0.27-0.39). MBI effects were significantly associated with minutes investigators meditated in the past 24 hours (p=0.05) and number of times investigators meditated in the past 7 days (p<0.01), with those meditating >30 minutes (g=0.51 [0.35-0.66]) and more than 7 times (g=0.52 [0.39-0.65]), respectively, displaying the highest effect sizes.

Conclusion: These findings confirm the benefit of MBIs in youth. We provide novel evidence that greater investigator MPH is significantly associated with better treatment outcomes. The results may invite a new way of thinking about and evaluating the mental health treatment literature and may motivate similar studies in other populations or interventions.