Tolerance to the impairing effects of alcohol on the inhibition and activation of behavior

Rationale Moderate doses of alcohol impair response inhibition and slow response activation, and some recent work has shown that during a single dose, response inhibition recovers from the impairing effects of alcohol more slowly than response activation. Evidence for a possible lag in tolerance development to inhibitory versus activational mechanisms suggests that as blood alcohol declines, drinkers' response inhibition might continue to be impaired despite having an unimpaired ability to activate responses; however, this effect has not been studied across repeated doses. Objective The present study examined how cross-session tolerance to the impairing effects of alcohol develops differentially between response activation and inhibition. Methods Thirty-two healthy adults performed a cued go/no-go task that measured response activation and inhibition. The study tested the degree to which response activation and inhibition developed acute and cross-session tolerances to a moderate dose of alcohol (0.65 g/kg) administered twice on separate days. Results Alcohol slowed response activation and decreased response inhibition during both administrations. Response activation displayed acute tolerance to alcohol impairment during both administrations and cross-session tolerance from the first to second administration. By contrast, response inhibition showed no acute or cross-session tolerance. Conclusion Biased recovery of response activation over inhibition during a single dose and as doses are repeated could contribute to some of the impulsive behavior commonly observed under alcohol.