Executive control deficits in substance-dependent individuals: A comparison of alcohol, cocaine, and methamphetamine and of men and women

Abstract

Substance dependence is associated with executive function deficits, but the nature of these executive defects and the effect that different drugs and sex have on these defects have not been fully clarified. Therefore, we compared the performance of alcohol- (n  = 33; 18 women), cocaine- (n = 27; 14 women), and methamphetamine-dependent individuals (n = 38; 25 women) with sex-matched healthy comparisons (n = 36; 17 women) on complex decision making as measured with the Iowa Gambling Task, working memory, cognitive flexibility, and response inhibition. Cocaine- and methamphetamine-dependent individuals were impaired on complex decision making, working memory, and cognitive flexibility, but not on response inhibition. The deficits in working memory and cognitive flexibility were milder than the decision-making deficits and did not change as a function of memory load or task switching. Interestingly, decision making was significantly more impaired in women addicted to cocaine or methamphetamine than in men addicted to these drugs. Together, these findings suggest that drug of choice and sex have different effects on executive functioning, which, if replicated, may help tailor intervention.

Keywords:

• Decision making
• Cognitive control
• Alcohol dependence
• Cocaine dependence
• Methamphetamine dependence
• Sex

Supported by National Institute on Drug Abuse (NIDA) R01 DA022549 and R01 DA11779. We thank Cynthia Cutshall and Jill Arnold for their invaluable assistance in testing the participants of this study and collecting the data. The authors would also like to thank Mariette Huizinga for providing the computerized tasks and Rupa Gupta for helpful comments during the process of writing the manuscript. Finally, we thank the anonymous reviewers for their constructive remarks on earlier versions.