The impact of neuropsychological functioning on adherence to HAART in HIV-infected substance abuse patients

Abstract

This study assessed the frequency of neuropsychological impairment and its relationship to adherence in a sample of HIV-infected injection drug users (IDUs) in treatment. One hundred eight participants recruited between September 2006 and October 2008 completed psychodiagnostic and neuropsychological assessments and monitored HAART adherence over a 2-week period via the use of Medication Event Monitoring System (MEMS) electronic pill caps and self-report. Assessment of concurrent functioning included clinician-rated scales of depression and substance use severity, and a battery of neuropsychological tests. Findings from individual neuropsychological tests were converted to Z scores relative to standard norms and averaged to form a composite score (NPZ). NPZ was generally poor (mean = -1.505, standard deviation = 1.120), with 76.9% of the sample being classified as highly impaired. Self-reported adherence was significantly higher than MEMS cap adherence. In contrast with previous studies, overall neuropsychological functioning was not a significant predictor of electronically monitored or self-reported adherence. However, examiner-rated current global severity of substance use and delayed word list recall emerged as significant predictors of self-reported adherence. Additionally, estimated premorbid verbal intelligence emerged as a significant predictor of the discrepancy between electronically monitored and self-reported adherence. Given the extent of neuropsychological impairment in this sample, future studies should examine the degree to which the impact of neuropsychological impairment may moderate interventions for this population, and the extent to which skills to cope with neuropsychological problems may boost the potential efficacy of such interventions.