Prevalence of Dropout and Influencing Factors in Digital Psychosocial Intervention Trials for Adult Illicit Substance Users: Systematic Review and Meta-Analysis

Abstract

Background: Illicit drug use has become a significant global public health issue, and digital interventions offer new approaches to address this challenge. However, there is a gap in existing research on the dropout rate of adult illicit drug users receiving digital psychosocial interventions. Objective: This study aims to evaluate the dropout rate of adult illicit drug use following digital psychosocial interventions during treatment and the longest follow-up, as well as its predictive factors. Methods: Following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, studies published up to August 27, 2025, were searched in the Web of Science, PubMed, PsycINFO, Embase, and Cochrane Controlled Trials Register. Randomized controlled trials of digital psychosocial interventions for adult illicit drug users that reported dropout rates were included. Two researchers independently screened studies, extracted data, and assessed bias risk using the Cochrane risk of bias tool (ROB 2.0). A random-effects model in Comprehensive Meta-Analysis software (CMA 4.0) was used for meta-analysis, along with heterogeneity testing, sensitivity analysis, and publication bias assessment. Finally, a moderating analysis was conducted based on the extracted data. Results: A total of 41 studies involving 9693 participants and reporting 48 dropout rates were included. The mean dropout rate in the intervention group after 18 studies was 22% (95% CI 0.13‐0.36), which was lower than the control group’s 26% (95% CI 0.16‐0.39). High heterogeneity was observed between studies (Q=396.18, df=17, P