2 Clinical Trials for Various Conditions
Background: - Previous research has shown that dopamine, a brain chemical, is involved in decision making. Different genes influence how much dopamine people have in their brains and how that affects their behavior. Researchers will study if genes associated with dopamine affect decision making and impulsiveness. All participants will take tests; some will have brain images taken. Researchers will study the test responses and images; they will look for how differences in these genes affect different types of decision making. Objectives: - To see if genes involved in a brain chemical, dopamine, are related to impulsiveness on behavioral tests. Eligibility: - Healthy adults ages 18 to 55. Design: * Participants will be screened with a medical history and physical exam. * All participants in this study will have at least 1 outpatient visit to the NIH Clinical Center. Each visit will last 2 4 hours. At the first visit: * A blood sample will be taken only from participants that have not been previously enrolled in 95-M-0150 * Participants will be given tests of their memory, attention, concentration, and thinking. * Some participants will have a second visit. It will be scheduled as soon as possible after the first. At the second visit: * Participants will have an MRI (magnetic resonance imaging). They will have to lie in a scanner for up to 2 hours. The MRI uses magnets, radio waves, and computers to produce detailed pictures of the brain. * Participants will repeat the tests from the first visit. Some will be done during the MRI.
Background: - People who are dependent on alcohol drink even when they know something bad might happen. Researchers want to learn more about why they do this. Objectives: - To study brain response when a person plays a game in different threat conditions. Eligibility: * Healthy right-handed adult heavy drinkers age 21 60 * Healthy right-handed adult light drinkers age 21 60 Design: * Participants will be screened with medical history, physical exam, and blood and urine tests. They will have an EKG and psychiatric interview. * Participants will have one or two clinic visits. * Participants will be asked about their alcohol drinking. * They will choose a snack and alcoholic beverage that they must drink in 5 minutes. After their breath alcohol content (BrAC) is zero, they will play a game in the MRI scanner. * The scanner is a metal cylinder that takes pictures of the brain. Participants lie on a table that slides in and out of the cylinder. They will be in it for about 90 minutes, lying still for up to 20 minutes. * During the MRI, participants will play a simple computer game to earn food or drink points under different threats of electric shock. Points can be exchanged for food or alcohol after the game. Sometimes, participants will receive a mild electric shock through a metal disk on the wrist. Electric shocks will only happen if the participant tries to earn a reward point. * After the MRI, participants use their points for another drink and snack. They will stay at the clinic until their BrAC is low, usually within 3 hours. Participants cannot drive themselves home. * Participants will have a follow-up phone call the next day.