Dropout From Face-to-Face, Multi-Session Psychological Treatments for Problem and Disordered Gambling: A Systematic Review and Meta-Analysis

Objective: The aims of this systematic review and meta-analysis were to examine the overall prevalence of dropout from psychological treatments for problem gambling and gambling disorder and to examine how study, client, and treatment variables influenced dropout rates. Method: A systematic search was conducted to identify studies of cognitive and/or behavioral therapies and motivational interventions for problem gambling and gambling disorder. Meta-analysis was used to calculate an overall weighted dropout rate. Random effect meta-regressions were used to examine covariates of dropout rates. Mixed-effect subgroup analyses were used to examine moderators of dropout rates. Results: The systematic search identified 24 studies (31 dropout rates) comprising 2,791 participants. Using a random-effects model, the overall weighted dropout rate was 39.1%, 95% CI [33.0%, 45.6%]. Increases in the percentage of married participants were significantly associated with lower dropout rates. Dropout rates were significantly higher when dropout was defined as attending all sessions of a treatment protocol compared to when defined as attending a prespecified number of sessions different from the total in the protocol and when defined as study therapists judging participants to be dropouts. Insufficient reporting of some gambling-related variables and other psychological symptom variables prevented a thorough examination of covariates and moderators. Conclusions: A large proportion of individuals drop out of treatment for problem gambling and gambling disorder. Future research should examine the reasons for dropout across marital statuses and should adopt dropout definitions that consider session-by-session symptom change. Public Health Significance Statement This review suggests that a significant proportion of individuals drop out of psychological treatments for problem gambling and gambling disorder. This review also recommends that the field adopt symptom-based dropout definitions to determine the adequate dosage of psychological treatment for problem gambling and gambling disorder.