Biphasic alcohol response differs in heavy versus light drinkers

BACKGROUND: Most studies of risk factors for alcohol-related problems have focused on biological family history as a primary risk factor. However, other factors, such as early-age heavy drinking, are also risk factors for sustained or progressive heavy consumption. Little is currently known about the mechanisms underlying binge or heavy drinking. METHODS: This study examined the acute subjective and objective effects of ethanol in heavy drinkers versus light drinkers. Thirty-four subjects participated in this within-subjects study consisting of three early-evening testing sessions in which subjects consumed a beverage containing either 0.8 or 0.4 g/kg ethanol or placebo. RESULTS: Compared with lighter drinkers, heavy drinkers were more sensitive to the positive stimulant-like effects of ethanol (p < 0.05), especially during the increasing limb of the blood alcohol curve. Heavy drinkers also showed less sedation and cortisol response after alcohol than the light drinkers (p < 0.05). CONCLUSIONS: The results indicate that young adult binge drinkers show a biphasic alcohol response, with heightened sensitivity to stimulant-like alcohol effects and greater tolerance to sedative alcohol effects compared with their light-drinking counterparts.