Effects of heavy drinking on next-day neurocognitive performance

Background: Residual effects the day after heavy drinking may cause cognitive and physical impairment in functions critical to safety-sensitive occupations. Methods: We conducted a double blind, randomized, placebo-controlled, crossover study of effects of heavy drinking (mean BrAC 0.11 g% ± 0.01) on next-day sustained attention/reaction time (psychomotor vigilance test- PVT), neurocognitive performance (neurobehavioral evaluation system-NES3), and subjective performance (self-report questionnaires). Participants were 97 healthy current students or recent graduates from Boston-area colleges (60 women, mean age 24.8 ± 2.7 years). Participation included evening beverage consumption of alcohol (high or low congener) or placebo (counterbalanced), and testing the following morning when BrAC was at zero. Sleep was assessed with polysomnography. Results: The morning following alcohol, PVT median reaction time (ms) was significantly slower than under placebo conditions (230.8 ± 31.6 vs. 221.2 ± 24.6, p < .0001). Change scores for NES3 testing showed a significant deficit in visuospatial information processing (0.3 ± 1.2, p < .05) and an increase in anger (0.1 ± 0.5, p < .05) on a mood scale. Participants also self-reported greater impairment in performance on the post-alcohol mornings (p < 0.0001). Significant differences were observed on several measures of sleep architecture and continuity, indicating greater sleep disturbance following alcohol. Further analyses will evaluate beverage congener and sleep disturbance as possible mediators of cognitive outcomes. Conclusions: Our findings suggest that heavy drinking may affect next-day reaction time, visual perception, and mood state, even when blood alcohol is at zero. These findings could have implications for alcohol-related, occupational regulations.