Working memory deficits affect risky decision-making in methamphetamine users with attention-deficit/hyperactivity disorder

Abstract

Methamphetamine (MA) use and Attention-Deficit/Hyperactivity Disorder (ADHD) commonly co-occur and are independently associated with dysregulation of frontostriatal loops and risky decision-making; however, whether their comorbidity exacerbates risky decision-making is not known. This study evaluated 23 participants with histories of MA dependence and ADHD (MA+ADHD+), 25 subjects with MA dependence alone (MA+ADHD-), and 22 healthy adults (MA-ADHD-), who completed the Iowa Gambling Task (IGT) as part of a larger neuropsychiatric research evaluation. Results showed a significant interaction between ADHD, MA, and working memory, such that individuals with working memory deficits in the MA+ADHD+ cohort demonstrated the strongest propensity to select cards from "disadvantageous" versus "advantageous" decks on the IGT. This effect was not better explained by other psychiatric, substance use, neuromedical, or cognitive factors. Findings suggest that working memory deficits may moderate the expression of risky decision-making in MA users with ADHD.