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, Setting And Participants: 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. Searched databases included: PsycINFO, Web of Science, Medline, Cochrane Library and ProQuest Dissertations and Theses. Included as participants were 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% confidence interval (CI) = -0.07, 0.12, p = 0.60, indicating no significant difference. Larger effect sizes were found for studies using non-alcoholic control drinks (Hedges' g = 0.30, 95% CI = 0.01, 0.58) compared to placebo beverages (Hedges' g = -0.03, 95% CI = -0.13, 0.06), Cochran's Q = 4.67, p = 0.03.

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.