Assessment of cognitive functioning of methadone-maintenance patients: impact of adult ADHD and current cocaine dependence.

The purpose of this study was to determine if methadone-maintained patients (MMP) with cocaine dependence (CD) and/or adult Attention Deficit Hyperactivity Disorder (ADHD) exhibited compounded cognitive dysfunction associated with their poly-substance use and/or co-morbid psychiatric diagnoses. The sample consisted of 79 MMP (59% male, 51% Caucasian), maintained on methadone doses ranging from 40-130 mg/day, who were placed into one of four diagnostic categories: (1) a control group (no ADHD, no CD) (n = 24), (2) CD alone (n = 18), (3)ADHDalone (n = 18), and (4)ADHD+ CD(n = 19). The California Computerized Assessment Package (CalCAP) was administered to assess cognitive functioning requiring focused and sustained attention in a standardized fashion. There were no group differences on Simple Reaction tasks. Compared to the control group, the ADHD+ CD group was slower and less accurate on 33% of the Choice Reaction (CR) tasks. Specifically, individuals in the ADHD + CD group and the ADHD alone group performed significantly worse on tasks measuring attention and psychomotor responding. These tasks are associated with broader cognitive skills in working memory, language discrimination and flexibility of cognitive sets that may have implications for treatment outcome. Diagnostic services capable of identifying cognitive deficits among MMP with ADHD and/or CD are needed to maximize the likelihood of treatment success and to serve as an indicator for the efficacy of therapeutic approaches.