Meth Use, HIV Infection Linked to Changes in Brain Structure That Can Impair Cognitive Functions, Study Says

Methamphetamine use and HIV infection might significantly alter the size of a person's brain structure, leading to cognitive function impairments such as difficulties learning or processing information, according to a study published in the August issue of the American Journal of Psychiatry, CQ HealthBeat reports (CQ HealthBeat, 8/11). Terry Jernigan of the University of California-San Diego and colleagues conducted brain scans to examine structural volume changes in 103 adults from four groups: HIV-positive meth users, HIV-negative meth users, HIV-positive people who did not use meth and HIV-negative people who did not use meth. Researchers also assessed participants' thinking and reasoning abilities through a series of tests that studied information processing speed, attention or working memory, learning and delayed recall, abstraction or executive functioning, verbal fluency and motor functioning.

Study Findings, Next Steps
The researchers found that meth use increased the volume of the brain's parietal cortex, which helps people understand and pay attention to their surroundings, and the basal ganglia, which affects motor function and motivation. HIV infection was linked to volume loss in the cerebral cortex, which is used for thought, reasoning and memory; the basal ganglia; and the hippocampus, which is needed for memory and learning. The extent of size increase in the parietal cortex was linked to deteriorated cognitive function, according to the study. Researchers saw no link between the amount of meth used and changes in brain size. However, the findings suggest that younger meth users were more affected in some areas of the brain than older meth users. Researchers also found a link between the severity of HIV-infection and the loss of brain matter (NIH release, 8/11). In addition, the study found that concurrent meth use and HIV infection might cause greater cognitive impairment than each condition on its own (CQ HealthBeat, 8/11). According to Nora Volkow of NIH's National Institute on Drug Abuse, which supported the study, the findings could lead to better therapies and could be a useful guide for future studies (NIH release, 8/11).

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