Background This study assessed the effects of heavy drinking with high or low congener beverages on next-day neurocognitive performance, and the extent to which these effects were mediated by alcohol-related sleep disturbance or alcoholic beverage congeners, and correlated with the intensity of hangover. Methods Healthy heavy drinkers age 21–33 (n = 95) participated in two drinking nights after an acclimatization night. They drank to a mean of 0.11 g% BrAC on vodka or bourbon one night with matched placebo the other night, randomized for type and order. Polysomnography recordings were made overnight; self-report and neurocognitive measures were assessed the next morning. Results After alcohol, people had more hangover and more decrements in tests requiring both sustained attention and speed. Hangover correlated with poorer performance on these measures. Alcohol decreased sleep efficiency and REM sleep, and increased wake time and next-day sleepiness. Alcohol effects on sleep correlated with hangover but did not mediate the effects on performance. No effect of beverage congeners was found except on hangover severity, with people feeling worse after bourbon. Virtually no sex differences appeared. Conclusions Since drinking to this level affects complex cognitive abilities, safety could be affected, with implications for driving and for safety sensitive occupations. Congener content affects only how people feel the next day so does not increase risk. The sleep disrupting effects of alcohol did not account for the impaired performance so other mechanisms of effect need to be sought. Since hangover symptoms correlate with impaired performance, these might be contributing to the impairment.

Purpose-No psychometrically established measure of acute hangover symptoms is published and available to use in experimental investigations. The present investigation combined data across three studies of residual alcohol effects to establish the properties of a new Acute Hangover Scale (AHS) based on symptoms supported in previous lab studies.Methods-Professional mariners from a Swedish maritime academy (n = 54) and young adult students/recent graduates of urban U.S. universities (n = 135) participated in one of three withinsubjects' studies of residual effects of heavy drinking (M = .114 g% breath alcohol concentration [BrAC]). All drank placebo one evening and alcoholic drinks another evening followed by an 8-hour sleep period before completing the AHS 10-20 min after awakening.Results-The AHS showed excellent internal consistency reliability the morning after alcohol. The AHS mean score and each item were significantly affected by beverage but not demographics or typical drinking, supporting validity.Conclusions-The AHS is a reliable and valid instrument for assessing acute hangover symptoms in experimental investigations of residual alcohol effects.