AIDS dementia complex typically occurs after years of HIV infection and is associated with low CD4+ T cell levels and high plasma viral loads. It is sometimes seen as the first sign of the onset of AIDS. Prevalence is between 10-24% in Western countries and has only been seen in 1-2% of India-based infections.
With the advent of highly active antiretroviral therapy (HAART), the incidence of ADC has declined in developed countries, although its prevalence is increasing. HAART may prevent or delay the onset of ADC in people with HIV infection, and may also improve mental function in people who already have ADC.

Dementia only exists when neurocognitive impairment in the patient is severe enough to interfere markedly with day-to-day function. That is, the patient is typically unable to work and may not be able to take care of him or herself. Before this, the patient is said to have a mild neurocognitive disorder.

Adapted from Wikipedia, the free encyclopedia. Accessed on April 30.