Faster alcohol metabolism is associated with increased stimulation and within session consumption

Variability in subjective response (SR) to alcohol predicts drinking and the development of Alcohol Use Disorders (AUDs). Although both alcohol pharmacokinetics (i.e., absorption and metabolism) and SR are impacted by aspects of the drinking situation (e.g., rate of consumption), relations between individual differences in pharmacokinetics and SR have received little attention. The current study examined the extent to which alcohol pharmacokinetics impact SR and drinking during a single alcohol administration session. A total of 119 (67% male) social drinkers were administered a dose of alcohol with a target blood alcohol concentration (BAC) of 0.08g%. The Biphasic Alcohol Effects Scale was administered twice at matched ascending and descending limb BACs following alcohol consumption to assess SR. Pharmacokinetic properties (absorption and metabolism) were inferred using multiple BAC readings to calculate the area under the curve during the ascending limb (absorption) and descending limb (metabolism). Following completion of SR measures, an ad libitum taste rating task utilizing nonalcoholic beer was implemented to assess voluntary 'alcohol' consumption. Results indicated that participants who metabolized alcohol more quickly maintained a greater level of subjective stimulation on the descending limb. Faster metabolism was indirectly related to ad lib nonalcoholic beer consumption through greater maintenance of stimulant effects. Absorption did not significantly predict SR or within session drinking. The results increase understanding of SR variability and suggest that heightened stimulation that is sustained across limbs of the BAC curve may increase risk for excessive consumption. Individual differences in alcohol metabolism may be an identifiable biomarker of this high risk pattern of SR.