• INCLUSION CRITERIA:

Controls:

1. No psychiatric or severe chronic medical illness at the time of the study, and by history. This includes the absence of substance abuse histories, learning disabilities and all DSM IV disorders. The investigators will evaluate medical histories and medical conditions that are judged not to interfere with the study may be allowed.
2. No use of psychotropic substances in the last 3 months.
3. There is no upper age limit the lower age limit is 18 years.

Patients:

1) Schizophrenia, any subtype or schizoaffective disorder according to DSM IV, as detailed in protocol # 89-M-0160 ("Inpatient evaluation of neuropsychiatric inpatients", Dr. Jose Apud, principal investigator) and # 95-M-0150 ("A Longitudinal Investigation of Siblings of Schizophrenic and Manic-Depressive Patients", Dr. Daniel R. Weinberger, principal investigator).

EXCLUSION CRITERIA:

Controls and patients:

1. Impaired hearing.
2. Pregnancy (only for purpose of MRI procedures under separate protocols)
3. Head trauma with loss of consciousness in the last year or any evidence of functional impairment due to and persisting after head trauma. Patients or healthy volunteers with a known risk from exposure to high magnetic fields (e.g. patients with pace makers) and those who have metallic implants (e.g. braces) in the head region (likely to create artifact on the MRI scans) will be excluded from participating in the fMRI studies.

Patients:

1. Coexistence of another major mental illness at the time of the study. If the patients experienced other mental illnesses in the past (e.g. a learning disability or major depression), then this should be judged to be fully recovered.
2. Criteria for substance abuse met in the last 6 months.
3. Criteria for substance dependence met in the last year. If criteria for dependence were met in the past, then the duration of the disorder was less than 3 years, or not judged to have produced long-term brain changes to allow the patient to be in the study.
4. Major concurrent medical illness likely to interfere with the acquisition of the task.
5. Concomitant medications which could interfere with performance on the task.
6. Presence of dyskinetic movements of the face and tongue (likely to interfere with eyeblink measures), or of gross involuntary movements of the whole body (likely to interfere with positioning in the MRI scanner).