Independent effects of HIV infection and cocaine dependence on neurocognitive impairment in a community sample living in the southern United States

Background: Prior studies have established that methamphetamine and HIV can have additive deleterious effects on neurocognitive functioning, but there has been relatively little research on other stimulants like cocaine. This study investigated the effects of cocaine and HIV on neurocognitive impairment in a large, well-characterized sample. Methods: The sample included 193 adults across four groups: HIV-positive cocaine users (n = 48), HIV-negative cocaine users (n = 53), HIV-positive non-drug users (n = 60), and HIV-negative non-drug users (n = 32). Cocaine users met criteria for lifetime dependence and had past-month cocaine use. A comprehensive battery assessed substance abuse and neurocognitive functioning. Results: Participants were mostly male (66%) and African-American (85%), with a mean age of 46.09 years. The rate of global impairment was 33%, with no significant main effects across groups on likelihood of impairment. There were main effects for cocaine on processing speed and executive functioning, with cocaine users having greater impairment (F=9.33 and F=4.22, respectively), and for HIV on attention, with HIV-infected persons having greater impairment (F=5.55). There was an interaction effect for executive functioning, with the three patient groups having greater impairment than controls (F=5.05). Nonparametric analyses revealed significant additive impairment in the presence of both HIV and cocaine for processing speed. Conclusions: While cocaine does not appear to increase vulnerability to global HIV-associated neurocognitive impairment, it does have independent adverse effects on executive functioning and processing speed. Given prior evidence that domain-specific deficits predict real-world impairments, our results may help explain the poorer behavioral and functional outcomes observed in HIV-infected cocaine users. (C) 2015 Elsevier Ireland Ltd. All rights reserved.