A systematic review of the next‐day effects of heavy alcohol consumption on cognitive performance

BACKGROUND AND AIMS: Studies examining the next‐day cognitive effects of heavy alcohol consumption have produced mixed findings, which may reflect inconsistencies in definitions of ‘hangover’. Recent consensus has defined hangover as ‘mental and physical symptoms, experienced the day after a single episode of heavy drinking, starting when blood alcohol concentration (BAC) approaches zero’. In light of this, we aimed to review the literature systematically to evaluate and estimate mean effect sizes of the next‐day effects of heavy alcohol consumption on cognition. METHODS: Embase, PubMed and PsycNET databases were searched between December 2016 and May 2018 using terms based on ‘alcohol’ and ‘hangover’. Studies of experimental designs which reported the next‐day cognitive effects of heavy alcohol consumption in a ‘hangover’ group with BAC < 0.02% were reviewed. A total of 805 articles were identified. Thirty‐nine full‐text articles were screened by two independent reviewers and 19 included in the systematic review; 11 articles provided sufficient data to be included in the meta‐analysis; 1163 participants across 19 studies conducted since 1970 were included in the analysis. Data for study design, hangover severity, BAC at testing and cognitive performance were extracted and effect estimates calculated. RESULTS: The systematic review suggested that sustained attention and driving abilities were impaired during hangover. Mixed results were observed for: psychomotor skills, short‐ (STM) and long‐term memory (LTM) and divided attention. The meta‐analysis revealed evidence of impairments in STM [g = 0.64, 95% confidence interval (CI) = 0.15–1.13], LTM (Hedges’ g = 0.59, 95% CI = 0.01–1.17) sustained attention (g = 0.47, 95% CI = 0.07–0.87) and psychomotor speed (Hedges’ g = 0.66, 95% CI = 0.31–1.00) during alcohol hangover. CONCLUSION: The research literature suggests that alcohol hangovers may involve impaired cognitive functions and performance of everyday tasks such as driving.