Does Acute Alcohol Consumption Increase Risk-Taking while Gambling? A Systematic Review and Meta-Analysis.

AIMS To estimate the effect of acute alcohol consumption on risk-taking while gambling, examine blood alcohol concentration as a moderator, and explore possible moderators of this effect. DESIGN A systematic review and meta-analysis was completed. A Boolean search strategy was used to identify studies that included (a) alcohol consumption as an independent variable; (b) a gambling or risk-taking task; (c) a control or placebo comparison; (d) human participants; and (e) English publications. Descriptive information, sample characteristics, and experimental data were extracted from each study. SETTING Searched databases included: PsycINFO, Web of Science, Medline, Cochrane Library, and ProQuest Dissertations and Theses. PARTICIPANTS Experiments that compared the effects of alcohol and non-alcoholic or placebo beverages on risk-taking while gambling. MEASUREMENT Comprehensive Meta-Analysis version 3.3.070 was used. Standardized mean differences of risk-taking while gambling between the experimental and control conditions were calculated when studies did not report effect sizes. Random effects models were used for overall effect and meta-regressions while mixed effects models were used for subgroup analyses. FINDINGS Twenty articles containing 47 alcohol versus control comparisons met inclusion criteria. The overall Hedges' g for the difference between groups consuming alcohol and groups consuming a placebo or non-alcoholic drink control was 0.03, 95% CI [-.07, 0.12], p =.60, indicating no significant difference. Larger effect sizes were found for studies using non-alcoholic control drinks (Hedge's g = .30, 95% CI [.01, 0.58]) compared to placebo beverages (Hedge's g = -0.03, 95% CI [-0.13, 0.06]), Q(1)=4.67, p = .03. CONCLUSIONS Finding that acute alcohol consumption had no reliable effect on risk-taking while gambling was consistent with existing animal research. No support was found for the relation between alcohol dose and risk-taking. The significantly larger effect size for experiments using non-alcoholic versus placebo beverages suggests the potential role of expectancy effects.