Executive functions among individuals with methamphetamine or alcohol as drugs of choice: preliminary observations

Substance dependent individuals (SDIs) are frequently, but not invariably, impaired on tasks of executive functions. In this study, we examine patterns of executive performance among subjects with different self-reported "drug of choice" (defined as substance used>80% of the time prior to abstinence). Subjects were 33 abstinent SDIs receiving inpatient treatment and 19 non-SDI normal controls (NC) well-matched on age, sex, ethnicity, and VIQ, who were assessed using the Iowa Gambling Task (GT) and a delayed non-match to sample task (DNM): measures of decision making and working memory, respectively. Seventeen SDIs identified alcohol (AL group) and 16 SDIs identified methamphetamine (METH group) as their drug of choice. Overall, the METH group performed more poorly than the NC and AL groups on both tasks, with the largest differences observed in working memory. The AL group was not significantly impaired overall compared to NCs on either task, but showed subtle abnormalities of GT performance similar to the METH group. These preliminary findings suggest that self-reported drug of choice on admission to treatment may be associated with different patterns of executive performance during early recovery.