HIV-1 infection and intravenous drug use: longitudinal neuropsychological evaluation of asymptomatic subjects.

A previous baseline cross-sectional comparison of cognitive performance of a group of AIDS-free, HIV-seropositive intravenous drug users with seronegative control intravenous drug users revealed no significant differences attributable to HIV. We now present longitudinal follow-up results from the same cohort of 160 intravenous drug users. There were no differences in performance by serostatus group at either 6- or 12-month follow-up visits, although differences by age and education were observed. Improvement in performance secondary to practice effects was comparable in both serostatus groups. These findings confirm that chronic intravenous drug use may be associated with a wide range of neuropsychological deficits, but there is no evidence that such preexisting deficits interact with HIV infection to produce additional cognitive impairment in otherwise asymptomatic intravenous drug users. Together with results from other high-risk groups such as homosexual/bisexual men and hemophiliacs, these results confirm that neurocognitive abnormalities during the presymptomatic stages of HIV infection are rare, regardless of the route of acquisition of the virus.