Alcohol-induced performance impairment in heavy episodic and light social drinkers

Objective: The purpose of this study was to examine performance effects of alcohol in young adult heavy drinkers (HDs) and light drinkers (LDs). Prior research has shown that HDs have alterations in subjective alcohol response in comparison with LDs, with greater reported stimulant-like effects and reduced sedative-like effects. It is unclear whether these quantitative differences extend to performance and objective effects. Method: Thirty-four subjects participated (20 HDs and 14 LDs) in three early evening individual alcohol challenge sessions. Subjects were examined on eye movement and psychomotor performance tasks before and several times after consuming either 0.8 g/kg or 0.4 g/kg ethanol or placebo beverage. Results: Alcohol produced similar impairment for the groups in psychomotor performance and saccadic velocity measures, with blood alcohol concentration dependent group differences on the smooth pursuit task and a marginally lower threshold for impairment for HDs on the saccadic latency task. Covarying for personality differences (i.e., disinhibition and boredom susceptibility traits) and family history of alcoholism did not significantly alter the findings. Conclusions: Despite prior findings of differential subjective response to alcohol in HDs and LDs, alcohol-induced performance impairment was comparable between the groups. Our findings suggest HDs may be particularly at risk for alcohol-related consequences because their greater sensitivity to positive alcohol effects and/or tolerance to sedative effects may not be accompanied by a lesser degree of alcohol-induced performance impairment.