A test of alcohol dose effects on multiple behavioral measures of impulsivity.

BACKGROUND

Acute alcohol administration affects impulsive behavior, although these effects vary as a function of alcohol dose, assessment instrument, and time of measurement following administration.

METHODS

We concurrently examined the dose-dependent effects of alcohol on three distinct types of impulsivity tasks (continuous performance [IMT], stop-signal [GoStop], and delay-discounting [SKIP] tasks). Ninety healthy alcohol drinkers were assigned to one of the three task groups (n=30 each), each group experienced placebo, 0.2, 0.4, 0.6, and 0.8 g/kg alcohol doses across 5 experimental days, and task performance was assessed at 0.5h before and 0.25, 1.0, and 2.0 h after alcohol administration. We hypothesized that impulsive responding on all tasks would be increased by acute alcohol administration both across time and during the peak BrAC, but the magnitude would depend on the task being tested. Analyses included the time course and the peak BrAC effects. Task comparisons of peak behavioral changes following each dose are illustrated using standardized scores.

RESULTS

While alcohol consumption increased impulsive responding during all three tasks to some extent, our hypothesis was only partially supported. During the IMT, the 0.6 and 0.8 g/kg doses produced increased impulsive responding across time and at the peak BrAC. However, during the GoStop and SKIP, impulsivity increased across time regardless of the alcohol dose size, with no differences in impulsive responding among dose conditions at peak BrAC.

CONCLUSIONS

This study demonstrated alcohol-induced changes in impulsivity are not uniformly affected by alcohol. These data, in conjunction with previous studies, further support that impulsivity is not a unitary construct.