Background: Despite a large number of empirical reports of impaired decision making in substance use disorders, the underlying factors contributing to such deficits remain to be elucidated. This study examined the potential influences of personality traits, affective symptoms, and pharmacological variables on decision making, as measured by the Iowa Gambling Task (IGT) in a sample of opioid-dependent patients.
Methods: A total of 46 opioid-dependent patients taking part in an opiate maintenance outpatient program and 46 healthy control subjects performed the IGT. Personality traits and affective symptoms were examined by using Zuckerman Sensation-Seeking Scale, the State-Trait Anxiety Inventory and Beck Depression Inventory. In addition, Cloninger Temperament and Character Inventory was administered in the patient group. Information on current and life-time substance use was acquired with a standardized interview.
Results: Opioid-dependent patients performed significantly worse on the IGT than controls. This difference disappeared after statistically controlling for trait anxiety, state anxiety, disinhibition, depressive symptoms, and lifetime alcohol consumption. Trait and state anxiety and self-directedness were significantly associated with the IGT final score. Hierarchical regression analyses suggested that self-directedness differentially moderated the relationships between the anxiety variables and IGT performance.
Conclusions: The decision-making impairments observed in opioid-dependent patients are influenced by current levels of anxiety and the personality markers trait anxiety and self-directedness. Differences in decision making between opioid-dependent and healthy individuals may also be due to differences in other personality facets, affective symptoms, and alcohol consumption. Amount of opioid and other substance intake did not show any effects. These results indicate that psychological characteristics may have a higher impact on decision-making performance than drug-induced pharmacological effects.