Impaired decision-making under risk in individuals with alcohol dependence

Background: Alcohol dependence is associated with poor decision-making under ambiguity, that is, when decisions are to be made in the absence of known probabilities of reward and loss. However, little is known regarding decisions made by individuals with alcohol dependence in the context of known probabilities (decision under risk). In this study, we investigated the relative contribution of these distinct aspects of decision-making to alcohol dependence.

Methods: Thirty recently detoxified and sober asymptomatic alcohol-dependent individuals and 30 healthy control participants were tested for decision-making under ambiguity (using the Iowa Gambling Task[IGT]) and decision-making under risk (using the Cups Task and Coin Flipping Task). We also tested their capacities for working memory storage (digit span forward) and dual tasking (operation span task).

Results: Compared to healthy control participants, alcohol-dependent individuals made disadvantageous decisions on the IGT, reflecting poor decisions under ambiguity. They also made more risky choices on the Cups and Coin Flipping Tasks reflecting poor decision-making under risk. In addition, alcohol-dependent participants showed some working memory impairments, as measured by the dual tasking, and the degree of this impairment correlated with high-risk decision-making, thus suggesting a relationship between processes subserving working memory and risky decisions.

Conclusions: These results suggest that alcohol-dependent individuals are impaired in their ability to decide optimally in multiple facets of uncertainty (i.e., both risk and ambiguity) and that at least some aspects of these deficits are linked to poor working memory processes.