Brain Imaging for HIV-Associated Thinking and Mood Disorders

Background: \- Human immunodeficiency virus (HIV) infection appears to cause problems with blood vessel function. These problems may add to some thinking and mood disorders found in people with HIV infection. Researchers want to evaluate HIV infected patients to see if blood vessel function contributes to thinking and mood disorders, such as early dementia and depression. To do so, they will compare study results between people with and people without HIV infection. Objectives: * To compare the thickness of blood vessel walls between people with and without HIV infection. * To study the relationship between blood vessel thickness and thinking and mood disorders. Eligibility: * Individuals between 25 and 55 years of age who have HIV infection. * Healthy individuals between 25 and 55 years of age. Design: * Participants will be screened with a physical exam and medical history. Blood and urine samples will be collected. * Participants will have imaging studies of the brain and major blood vessels in the head and neck. * Participants will also have neuropsychological testing. These tests will look at memory, learning and thinking ability, attention, and mood. * Participants will have the option of coming back for repeat blood tests every six months and repeat imaging studies and neuropsychological tests every year, over 1- 4 years period.