PET Imaging of the Dopaminergic and Serotonergic Systems in Treated HIV Positive Subjects

Background: Human immunodeficiency virus (HIV) infection is a serious disease with no cure. Some people with HIV have depression and other mood problems. They can have problems with thinking and memory. Researchers think 2 chemicals in the brain may cause those problems. The chemicals are serotonin and dopamine. The researchers want to take images to learn more about those chemicals in HIV patients. Objective: To learn how HIV affects serotonin and dopamine in the brain. Eligibility: Adults ages 18-70 with HIV who have been on antiretroviral treatment for at least 1 year Healthy adults ages 18-70 All participants must be already enrolled in protocol 13-N-0149. Design: * Participants will be screened with a urine drug test. The results could be shared with insurance companies. * Participants who could be pregnant will have a pregnancy test. * Participants may have a physical exam and blood tests. * Participants will have 1 or 2 positron emission tomography (PET) scans. A needle will guide a thin plastic tube (catheter) into an arm vein. A radioactive drug will be injected into the plastic tube. This is a tracer that helps researchers understand the PET images. * Participants who have the dopamine scan will have to fast for 4-6 hours before the scan. They will take a pill to help direct the tracer to the brain one hour before the scan. * Each scan will last about 1.5 hours. * Participants will be asked to drink a lot of fluids and empty their bladder frequently for the rest of the day after each scan.