Motivational-interviewing-informed interventions for problem gambling and gambling disorder: A systematic review and meta-analysis.

OBJECTIVE

To conduct a systematic review of motivational interviewing (MI) integrity in randomized controlled trials and to conduct a meta-analysis on the effect of MI-informed interventions compared to control conditions on gambling behavior and gambling disorder symptom severity at posttreatment and follow-up.

METHOD: Five databases were searched to identify published and unpublished studies of randomized controlled trials. Studies randomizing participants to a MI-informed intervention or a control condition that did not receive MI were eligible. A random-effects meta-analysis of Hedges's g effect sizes representing outcomes of MI-informed interventions versus control at posttreatment and follow-up was conducted.

RESULTS

Seven studies representing 796 participants were identified. MI-informed interventions varied greatly in their descriptions, and no intervention met the proposed criteria for establishing MI integrity in clinical trials (Miller & Rollnick, 2014). Outcomes between conditions were almost equivalent for gambling frequency (g = -0.04), gambling expenditure (g = -0.03), and gambling disorder symptom severity (g = 0.01) at posttreatment. Similarly, there was almost no difference in each outcome at follow-up (gs = -0.02, -0.02, and -0.10).

CONCLUSIONS

Overall, the findings indicated limited available knowledge to establish the integrity of MI and the efficacy of MI-informed interventions among individuals with problem gambling and gambling disorder. Based on the available evidence, previous meta-analyses have overestimated the isolated effect of MI-informed interventions on gambling behavior and gambling disorder symptom severity. Future research will require objective fidelity monitoring to ensure adherence to MI and use study designs that isolate the effect of MI interventions on gambling outcomes. (PsycInfo Database Record (c) 2025 APA, all rights reserved).