Since the discovery of AIDS in 1981 and HIV in 1983, important advances have been made in research into and the prevention and treatment of HIV-associated neurocognitive disorder (HAND). AZT, azidothymidine; CART, combination antiretroviral therapy; HNRC, HIV Neurobehavioral Research Center; MACS, Multicenter AIDS Cohort Study; UCSD, University of California San Diego.