View clinical trials related to Cocaine Abuse.
Filter by:Background: - Dopamine is a chemical signal linked to the rewarding effects of drugs. Certain genes make these effects sensitive to the time of day they are taken. Cocaine can affect these genes in the brain. Researchers want to measure brain dopamine at different times of day. Objectives: - To look for changes to a person s biological clock in the function of the dopamine reward system. To test if cocaine disrupts this. Eligibility: - Adults age 21-55 with a cocaine use disorder. - Healthy volunteers age 21-55. Design: - Participants will be screened with medical history, physical exam, interview, and blood and urine tests. Their breath will be tested for alcohol and recent smoking. - Participants will have 3 overnight clinic visits. - Visit 1: They will have blood and urine collected and a heart test. - A plastic tube (catheter) will be placed into a vein in each arm by needle. - Participants will have a PET scan in a donut-shaped machine. They will lie on a bed that slides in and out of it, wearing a cap. A radiotracer (measures dopamine) and a drug (blocks dopamine removal) will be injected via catheter. Vital signs will be measured and blood will be drawn throughout. - Visit 2: repeats Visit 1, except at night. - Visit 3, participants will have urine collected. - They will have MRI scans in a metal cylinder surrounded by a magnetic field. They will lie on a table that slides in and out of it, with a coil over their head. - Participants may answer questions, take computer or paper tests, and perform simple actions. - For 1 week, participants will wear a wrist device that measures daily activity.
Background: - Brain imaging studies, genetic research, and investigations of stress have provided more information about the role of dopamine in processing reward and punishment, and in vulnerability to substance dependence. Researchers are interested in learning more about how the brain responds to rewards, including drugs of abuse, and how these responses may involve genetic factors or previous stressful events. - Researchers intend to use the drug amphetamine to increase levels of dopamine in the brain and study the effects through two kinds of scanning: functional magnetic resonance imaging (fMRI) and positron emission tomography (PET). Objectives: - To examine the relationship among dopamine function, brain activity, reward processing, genetic profile and exposure to stress in normal healthy adults. - To examine the variation in these factors between normal healthy adults and individuals with current cocaine-dependence. Eligibility: - Individuals 18 to 45 years of age who are either current cocaine users or healthy volunteers with no history of substance abuse or dependence. Design: - The study will consist of an initial evaluation session and six study visits, four of which will involve fMRI scans (3 hours each) and two of which will involve PET scans (8 to 9 hours each). - Cocaine-using participants will enter the inpatient clinical research ward at the National Institute on Drug Abuse Addiction Research Center the night before each scanning session and will be discharged the following day. Healthy volunteer subjects will not be required to stay overnight and will arrive as outpatients for the PET session. Participants will not be released until researchers have determined that participants are not experiencing significant effects of the drug. - Initial session (1): Participants will complete questionnaires about past reactions to stressful situations, and will be trained to do thinking tasks that will be performed in fMRI visits. The tasks will be practiced in a mockup of an MRI machine. - MRI sessions (2-5): Participants will receive either oral amphetamine or a placebo, and will perform thinking, short-term memory, and reward tasks during MRI scanning as directed by researchers. - PET sessions (6-8): Participants will receive either oral amphetamine or a placebo, and will provide blood samples during the PET scanning sessions. Participants will have short breaks during the PET scanning sessions.