HIV-positive patients with past alcohol abuse appear to have a higher risk for cognitive problems than peers without such a history, suggesting that alcohol may make the brain more vulnerable to the later, infectious insult, according to an article in the February issue of the American Journal of Psychiatry.

American researchers evaluated 33 participants (12 HIV-negative, 21 HIV-positive) who met criteria for previous alcohol abuse. Those participants were compared with 47 people (18 HIV-negative, 29 HIV-positive) who reported no previous alcohol abuse or dependence. All subjects were analyzed through a battery of tests including an extensive neuropsychological examination, a diagnostic interview, and a number of psychiatric rating scales.

HIV-positive participants with a history of alcohol abuse showed statistically significant impairments in verbal IQ (decrease of 7.7 percent), verbal reasoning (decrease of 5.2 percent), and reaction time (approximately 10 percent slower with each hand) compared with HIV-positive patients without previous dependence on alcohol.

People in the study who had previous alcohol abuse but were HIV-negative showed no significant loss of cognitive function, suggesting that a history of alcohol abuse either adds to problems caused by HIV infection or that it has an interactive association with the infection’s effects on the brain, said Dr. Robert Bornstein, senior author of the study.

“This study suggests that previous alcohol abuse may create a point of vulnerability that is exacerbated by the effects of the virus on the brain. In contrast, in the absence of HIV infection, a past history of chronic alcohol abuse, combined with current abstinence from alcohol, appears to cause no significant cognitive impairment,” Bornstein noted. “There appears to be just enough alteration to cognitive function to make the brain more susceptible to the damaging impact of a second, independent process.”

“The findings related to abuse history cannot be attributed to current use of alcohol,” he said, noting that all participants with a history of dependence had no recent abuse experience. “But the findings also show that even if patients with HIV infection and a history of alcohol abuse make a significant lifestyle change by abstaining from alcohol, they are not protected from the apparent adverse effects of alcohol abuse when combined with HIV infection.