Treatment Dropout in Forensic Interventions: A Multilevel Meta-Analysis of Prevalence and Moderators.

Treatment dropout undermines the effectiveness of forensic mental health interventions aimed at reducing recidivism risk or reoffending. This multilevel meta-analysis synthesized controlled studies published since 2015 to estimate treatment dropout prevalence and examine relevant moderators. Searches identified 47 randomized and quasi-experimental studies (N = 9,362), yielding 67 dropout prevalence estimates. Three-level meta-analytic models accounted for statistical dependency among multiple estimates within studies. The pooled dropout prevalence was 28.49%. Age did not significantly moderate dropout rates. Offence type was a significant moderator, with particularly low dropout among individuals convicted of sexual and drugs-related acquisitive (approximately 12%). Program integrity significantly moderated dropout, with higher integrity associated with lower attrition. Trends further suggested higher dropout in treatment-as-usual compared with structured interventions, and lower dropout with greater treatment intensity. Overall, the findings suggest that stronger program integrity and the use of structured interventions may contribute to improved treatment retention in forensic populations.