Estimation of blood alcohol concentrations in young male drinkers

This research examined individual differences in the ability to self-monitor the effects of alcohol. Thirty-nine male subjects consumed 0.75 ml/kg alcohol and estimated their blood alcohol concentrations (BACs) at peak BAC and on the ascending and descending limbs of the blood alcohol curve. Family history of alcohol dependence did not affect the accuracy of estimation of BACs. Subjects who reported lower levels of subjective intoxication underestimated their BACs more than did subjects who reported higher levels of subjective intoxication. Subjects with less behavioral impairment underestimated their BACs more than subjects with greater behavioral impairment on the ascending limb of the blood alcohol curve. Accuracy was better on the ascending limb compared with peak BAC and the descending limb, and accuracy became worse over time on the descending limb. It appears that cues to the effects of alcohol rapidly become unavailable on the descending limb, which may contribute to decisions concerning further alcohol consumption and driving after drinking.