Predictors of decision-making on the Iowa Gambling Task: independent effects of lifetime history of substance use disorders and performance on the Trail Making Test

Abstract

Poor decision-making and executive function deficits are frequently observed in individuals with substance use disorders (SUDs), and executive deficits may contribute to poor decision-making in this population. This study examined the influence of lifetime history of an alcohol, cocaine, heroin, or polysubstance use disorder on decision-making as measured by the Iowa Gambling Task (IGT) after controlling for executive ability, demographic characteristics, and current substance use. Participants (131 with lifetime history of SUD and 37 controls) completed the IGT and two neuropsychological tests: the Trail Making Test and the Controlled Oral Word Association Test. Control participants performed significantly better than those with a lifetime SUD history on the IGT, but performance on the neuropsychological tests was comparable for the two groups. A lifetime SUD diagnosis was associated with performance on the IGT after controlling for covariates, and Trail Making Test performance was associated with IGT performance in both SUD and control participants.

Figure 1

Mean Iowa Gambling Task net scores for participants scoring below vs. above the median difference between completion times on Trail Making Test Parts A and B. Larger differences between Parts A and B indicate more impaired performance.

Figure 2

Mean Iowa Gambling Task net scores on each of five blocks of 20 draws. Data are presented separately for participants with substance use disorders performing below vs. above the median difference between completion times on Trail Making Test Parts A and B and for Control participants performing below vs. above the median. Larger differences between Parts A and B indicate more impaired performance.