Effects of chronic opioid dependence and HIV-1 infection on pattern shift visual evoked potentials

The goal of the present study was to examine the effects of opioid dependence, alone and in combination with asymptomatic HIV-1 infection, on the pattern shift visual evoked potential (PSVEP). For this purpose, three groups of patients were evaluated, including patients characterized by: (1) a past history (2-4 months abstinent) of DSM-IIIR opioid dependence (i.e. in partial remission); (2) a recent history (7 days abstinent) of opioid dependence with ongoing methadone maintenance; and (3) a recent history of opioid dependence, ongoing methadone maintenance, and asymptomatic HIV-1 infection. A group of healthy, non-drug dependent volunteers was also evaluated. Analyses revealed no PSVEP differences between patients with a past history of opioid dependence and healthy volunteers. There were also no PSVEP differences between methadone-maintained patients with or without HIV-1 infection. Collectively, however, the two methadone maintenance groups exhibited significant delays in the N75 and P100 components of the PSVEP relative to the other two groups. The delay in N75 latency was strongly correlated with self-reported years of heroin abuse, but not with years of cocaine, alcohol, or other drug abuse. These results are interpreted as reflecting an adverse effect of chronic opioid dependence on neural transmission within primary visual areas of the brain.