Decision-Making Task Performance and Patterns of Methamphetamine Use in People Assigned Male at Birth Who Have Sex With Men

This study aims to determine whether performance on the Iowa Gambling Task (IGT), a simulation of risk-taking when faced with loss, is associated with greater frequency of methamphetamine (MA) use and challenges reducing or stopping MA use. The parent mSTUDY is a Los Angeles County-based longitudinal study of substance use and HIV risk in predominately Black/African American and Latinx people assigned male at birth who have sex with men. The IGT was offered for a limited timeframe to mSTUDY participants, of whom 192 consented to and completed this one-time task. Separate random intercept binary logistic regressions tested whether the IGT total score and subscore for Blocks 4 and 5 (last 40 card draws) were associated with the outcomes, testing positive for MA in urine and self-reported inability to control or cease MA use in the past 6 months. Separate random intercept ordered logistic regressions tested whether IGT total score and subscore were associated with self-reported frequency of MA use in past 6 months. Higher IGT subscores for Blocks 4 and 5 (lower risk-taking) were associated with lower odds of testing MA-positive (adjusted odds ratio, AOR = 0.97, 95% CI [0.95, 0.99], p = .025) and less frequent MA use in the past 6 months (AOR = 0.96, 95% CI [0.94, 0.99], p = .006). Higher IGT total scores (lower risk-taking) were also associated with less frequent MA use (AOR = 0.99, 95% CI [0.97, 0.99], p = .038). Findings from this analysis suggest that IGT performance may be a useful indicator of MA use severity in nontreatment-seeking people.