Acute tolerance to alcohol-induced impairment in cognitive performance.

Abstract

Acute tolerance is a rapid decrease in the effect of alcohol relative to the blood alcohol concentration (BAC) occurring within the duration of a single dose of alcohol. It remains uncertain which cognitive domains are susceptible to acute tolerance, because findings vary between tasks used to measure the effect of alcohol. This study examined acute tolerance in subjective intoxication and in 2 cognitive domains: information processing, measured using the Inspection Time Task (ITT), and response inhibition, measured with the Sustained Attention to Response Task (SART). Forty participants were allocated to either an alcohol or placebo group. After baseline measures, the alcohol group were given an active dose to produce a peak BAC of 0.07%, whereas the placebo group received a placebo beverage. ITT and SART performance were measured at a BAC of 0.05% twice during the course of the dose, once when BAC was ascending and again when descending. The placebo group was tested at equivalent times. When BAC was ascending, the alcohol group showed increased ratings of subjective intoxication and impaired performance on the ITT. Consistent with an acute tolerance effect, ratings of subjective intoxication and impairment on the ITT in the alcohol group were lower when BAC was descending. Performance on the SART was not found to be affected by alcohol. The findings suggest information processing is a domain of behavior that shows acute tolerance to alcohol and that the subjective intoxication felt at a BAC of 0.05% can decrease substantially within the duration of a single dose.