The Edinburgh cohort of HIV-positive drug users: The effects of depressed mood and drug use upon neuropsychological function

The effect of the human immunodeficiency virus (HIV) on cognitive function drug users is subject to the effects of drug use and depression. The current study tested the effect of these potential confounders in 244 HIV-positive drug users (147 asymptomatic, 97 symptomatic) and 42 confirmed HIV-negative drug users. No difference was found between HIV-positive and HIV-negative groups for measures of drug use, negative mood, or verbal IQ. Symptomatic HIV-positive patients were significantly more impaired on measures of non-verbal performance intelligence and memory than HIV-negative or HIV-positive asymptomatic patients. Structural modelling of the data suggested associations between failing CD4 count and impaired non-verbal performance; low mood, greater benzodiazepine use and poorer memory; and higher opiate use and slight impairment on non-verbal performance. Drug use and low mood did not act upon low CD4 count to affect non-verbal cognitive performance. Our results suggest cognitive impairment in HIV-positive drug users attributable to HIV illness can be detected, and that concurrent drug use and mood are not major confounders, provided such factors are recognized to begin with.