Abstract
Substance Dependent Individuals (SDIs) usually show deficits in real-life decision-making, as illustrated by their persistence in drug use despite a rise in undesirable consequences. The Iowa Gambling Task (IGT) is an instrument that factors a number of aspects of real-life decision-making. Although most SDIs are impaired on the IGT, there is a subgroup of them who perform normally on this task. One possible explanation for this differential performance is that impairment in decision-making is largely detected on the IGT when the use of drugs escalates in the face of rising adverse consequences. The aim of this study is to test this hypothesis, by examining if several real-life indices associated with escalation of addiction severity (as measured by the Addiction Severity Index -ASI-) are predictive of risky decisions, as revealed by impaired performance on different versions of the IGT. We administered the ASI and different versions of the IGT (the main IGT version, a variant IGT version, and two parallel versions of each) to a large sample of SDI. We used regression models to examine the predictive effects of the seven real-life domains assessed by the ASI on decision-making performance as measured by the IGT. We included in regression models both ASI-derived objective and subjective measures of each problem domain. Results showed (i) that several aspects of real-life functioning associated with addiction severity were moderate predictors of IGT decision-making performance; (ii) that the combined assessment of decision-making using different versions of the IGT yielded better predictive measures than assessment using isolated versions of the IGT; and (iii) that objective measures of real-life functioning were better predictors of decision-making performance on the IGT than subjective measures based on SDI's insight about their problems. These results support the notion that decision-making deficits as measured by the IGT are associated with a rise in real-life adverse consequences of addiction.