INCLUSION CRITERIA:
Age: Participants will be males and females, 20-50 years of age.
IQ: IQ, as measured by 4 subscales from the Wechsler Adult intelligence Scale-Revised (WAIS-R), must be greater than 80.
Medication status: No current use of any psychotropic medications or benzodiazepine.
EXCLUSION CRITERIA:
Because factors such as psychiatric disease, or CNS disease, can influence functional brain activity, these factors are exclusionary.
Psychiatric History: Participants will be assessed using DSM-IV criteria via standardized psychiatric interviews conducted by trained examiners (i.e., SCID). All participants will be free of any current or past psychiatric disorder. In addition, participants with a first degree relative with depression will also be excluded.
Severe acute and chronic medical illnesses (e.g., cardiac disease, diabetes, epilepsy).
CNS disease: History of brain abnormalities (e.g., neoplasms, subarachnoid cysts), cerebrovascular disease, infectious disease (e.g., abscess), or other neurological disease, or history of head trauma (defined as loss of consciousness greater than 3 min).
Currently on any regular medication that would interfere with study results (with exception of contraceptive pill).
Currently breast feeding or pregnant (as documented by pregnancy testing at screening or at days of challenge studies).
Lactose intolerance is an exclusion criterion.
Additional exclusion criteria for fMRI studies:
Metal or electronic objects: Metal plates, certain types of dental braces, cardiac pacemakers, etc., that are sensitive to electromagnetic fields contraindicate MRI scans.
Claustrophobia: participants will be questioned about potential discomfort in being in an enclosed space, such as an MRI scanner.
Warren Grant Magnuson Clinical Center (CC)