Meth and the Amazing Shrinking Brain

HIV-positive people who use crystal methamphetamine are putting themselves at high risk of impaired brain function, according to a study in the August issue of the American Journal of Psychiatry. Researchers studying brain scans and cognitive tests of 103 HIV-positive and HIV-negative meth users discovered that HIV and meth together can cause significant loss of memory, motor control, verbal reasoning, and information processing speed. While it's been known that both meth use and HIV infection independently affect brain function, researchers discovered that the two together cause significant additional cognitive impairment. Meth use was shown to increase the volume of the brain's parietal cortex (which affected study subjects' awareness of their surroundings) and the basal ganglia (which control motor function and motivation). Meanwhile, HIV decreased brain volume in the cerebral cortex, which is associated with reasoning and memory; in the hippocampus, which is linked with learning and memory; and in the basal ganglia. Researchers found no link between the amount of meth used and changes in brain size, but their findings did indicate that younger meth users had a greater amount of affected brain area than older users. Dan Bowers reported in his Clinic column in the August 2005 issue of HIV Plus that meth use also may stimulate HIV replication and boost the risk of kidney disease and stroke.