Acute alcohol decreases performance of an instrumental response to avoid aversive consequences in social drinkers.

Background: Recent studies demonstrated that alcohol impairs inhibitory control of behavioural responses.

Aims: We questioned whether alcohol via its disinhibiting effects would also impair the inhibition of an instrumental avoidance response in the presence of a safety signal.

Design: Thirty-six moderate social drinkers were randomly allocated to receiving either alcohol (0.8 g/kg) or placebo before performing an instrumental avoidance procedure. White noise of 102 db was used as aversive outcome presented at a variable interval schedule in S+ trials, while no noise was presented in S- trials. An instrumental response (repeated space bar presses to avoid the noise presented at a variable interval) abolished the noise. The Stop Signal task and the affective Go/No-Go task were administered as inhibitory control tasks.

Results: Alcohol did not change the avoidance response rate in the presence of S- (safety signal). However, participants under alcohol performed the avoidance response to a lower extent than placebo subjects in S+ trials. Alcohol impaired performance in the Stop Signal task and increased the number of commission errors in the affective Go/No-Go task. Conditioned attentional and emotional responses to the S+ as well as knowledge of stimulus-response outcome contingencies were not affected by alcohol.

Conclusions: Acute alcohol may decrease the motivation to avoid negative consequences and thus might contribute to risky behaviour and binge drinking.