Brain Networks and Addiction Susceptibility

Study Summary

Background: \- The risk for becoming addicted to drugs varies from person to person, even among those using similar drugs in a similar way. Researchers do not fully understand why some people become addicted to drugs and others do not. Studies suggest that under certain life circumstances, some genes may increase the risk for addiction. This study will use genetic information, computer tasks, magnetic resonance imaging (MRI), and other tests to see what brain networks may be related to drug addiction. Objectives: \- To better understand brain networks that may be related to susceptibility to drug addiction. Eligibility: \- Healthy non-smoking volunteers between 18 and 55 years of age. Design: * This study will have one screening visit and four all-day study visits. For male participants, the visits will be about 7 days apart over 5 to 7 weeks. Female participants will have the visits scheduled to coordinate with their menstrual cycle. * This study involves small doses of three approved drugs: two oral dopamine drugs and a nicotine patch. For each scanning session, participants will have three study drugs. However, only one pill or patch will be the real drug; the other two will be placebos. Some participants may have only placebos during a visit. * Participants will be screened with a physical exam and medical history. Blood and urine samples will be taken. Other tests will be given to ensure that participants are not smoking or using drugs while they are in the study. * During the all-day scanning visits, participants will receive two pills and one patch in the morning and they will be trained on simple computer tasks. In the afternoon, participants will have MRI scans and we will measure their brain activity while they rest and while they perform computer tasks in the scanner. Participants will also answer questionnaires during the scanning visits.

Interventions

• DRUG Oral methylphenidate and Oral haloperidol