Dementia Is Linked to Dopamine Levels

HIV-positive people exhibiting early signs of dementia have significantly depleted levels of the brain chemical dopamine, according to a study published in the September issue of the British journal Brain. Brain scans showed that the levels of dopamine-producing cells in 15 HIV-positive adults'some of whom were showing signs of dementia'were 12% to 20% lower than the levels in their HIV-negative peers. 'This study clearly demonstrates that HIV infection damages dopamine- associated brain cells,' according to researcher Nora Volkow. A separate study in the August edition of Annals of Neurology showed that HIV infection may cause damage to parts of the brain and force reserve pathways to take over, which boosts the risks for overload of the brain attention network as well as risks of problems with attention and concentration. Researchers monitoring brain activity in 18 HIV-positive and 18 HIV-negative study subjects say that those infected with HIV had less brain activation in several areas of the brain, including regions affecting visual and cognitive performance.