Acute alcohol tolerance on subjective intoxication and simulated driving performance in binge drinkers.

High rates of binge drinking and alcohol-related problems, including drinking and driving, occur among college students. Underlying reasons for the heightened impaired driving rates in this demographic group are not known. The authors hypothesized that acute tolerance to the interoceptive cues of intoxication may contribute to these maladaptive decisions to drive in binge drinkers. Groups of binge-drinking and non-binge-drinking college students (N = 28) attended sessions during which they received a moderate dose of alcohol (0.65 g/kg) or a placebo. The development of acute tolerance to subjective ratings of intoxication and simulated driving performance was assessed by comparing measures taken during the ascending phase and descending phases of the blood alcohol curve. Compared with placebo, alcohol increased ratings of intoxication and impaired multiple aspects of simulated driving performance in both binge and non-binge drinkers. During the descending phase of the blood alcohol curve, binge drinkers showed acute tolerance to alcohol’s effect on subjective intoxication, and this effect was accompanied by an increased rating of willingness to drive. By contrast, non-binge drinkers showed no acute tolerance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Tonic and phasic processes in the acute effects of alcohol.

This article presents a novel method for measuring the acute effects of alcohol. One hundred twenty nonproblem drinkers aged 21-28 participated in 3 alcohol administration sessions that produced peak blood alcohol concentrations (BACs) near .09 g%. Subjective intoxication ratings were taken at multiple points across rising and falling BACs. Mathematical modeling techniques decomposed intoxication ratings into a tonic component sensitive to BAC level and a phasic component sensitive to BAC rate of change. This model provided a good fit to observed data. Tonic and phasic gain parameters showed high repeatability across sessions. The average phasic gain parameter was about 4 times larger than the average tonic gain parameter, indicating that subjective intoxication is usually more affected by BAC change than by BAC level. The associations of drinking practices with tonic and phasic gain parameters varied by gender and family history of alcoholism. Tonic-phasic modeling allows individual and group differences in the acute effects of alcohol to be studied as time-dynamic processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Alcohol-impaired speed and accuracy of cognitive functions: A review of acute tolerance and recovery of cognitive performance.

Much research on the effects of a dose of alcohol has shown that motor skills recover from impairment as blood alcohol concentrations (BACs) decline and that acute tolerance to alcohol impairment can develop during the course of the dose. Comparable alcohol research on cognitive performance is sparse but has increased with the development of computerized cognitive tasks. This article reviews the results of recent research using these tasks to test the development of acute tolerance in cognitive performance and recovery from impairment during declining BACs. Results show that speed and accuracy do not necessarily agree in detecting cognitive impairment, and this mismatch most frequently occurs during declining BACs. Speed of cognitive performance usually recovers from impairment to drug-free levels during declining BACs, whereas alcohol-increased errors fail to diminish. As a consequence, speed of cognitive processing tends to develop acute tolerance, but no such tendency is shown in accuracy. This "acute protracted error" phenomenon has not previously been documented. The findings pose a challenge to the theory of alcohol tolerance on the basis of physiological adaptation and raise new research questions concerning the independence of speed and accuracy of cognitive processes, as well as hemispheric lateralization of alcohol effects. The occurrence of alcohol-induced protracted cognitive errors long after speed returned to normal is identified as a potential threat to the safety of social drinkers that requires urgent investigation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)