Function of Catecholamines in the Brain During Depression

Study Summary

This study will explore brain function related to depressive symptoms and will examine DNA for genes that may be involved in depressive disorders, particularly genes that regulate synthesis and metabolism of the brain neurotransmitter catecholamine. It will compare findings in patients with major depressive disorders who are in remission with those in normal, healthy volunteers. Patients with remitted major depressive disorders and healthy normal volunteers between 18 and 60 years of age may be eligible for this study. Candidates are screened with a psychiatric and medical history, physical examination, electrocardiogram, and blood and urine tests. Participants undergo the following tests and procedures in up to eight visits to the NIH Clinical Center: Memory Tasks and Problem Solving and Brain Imaging Subjects are tested with measurements of intelligence or memory ability. They also undergo magnetic resonance imaging (MRI), a test that uses a magnetic field and radio waves to produce images of the brain. For this procedure, the patient lies on a table that is moved into the scanner (a narrow cylinder), and wears earplugs to muffle loud knocking and thumping sounds that occur during the scanning process. The MRI lasts about 60 minutes. Catecholamine Depletion Study For this study, subjects take capsules containing either AMPT (a drug that temporarily reduces brain catecholamine activity) or a placebo (lactose capsules, which do not affect brain catecholamine activity) at 9 a.m., 2 p.m., and 7 p.m. on one visit and return the next day to take additional capsules at 7 a.m. and noon. In addition to the study medication, subjects keep a low-monoamine diet (e.g., no chocolate, cheese, smoked meats, and various other foods that will be enumerated) and do not smoke, drink alcohol, or take in food or drink containing caffeine. After taking all the study capsules, the subjects have positron emission tomography (PET) and functional MRI (fMRI) scans, as follows: * fMRI: