Inclusion Criteria:

1. Patients will be aged 18-55, have no significant neurologic history, must meet DSM-IV criteria for a diagnosis of major depression and be free of antidepressant or other psychotropic medication for a minimum of two weeks before enrollment.
2. If a subject is talking psychiatric medication he/she may be weaned off of the medication by their treating physician prior to study enrollment. Such a course of action would only be advised if the current medication was not considered to be of any benefit to the subject.
3. In particular, if a patient is on antidepressant medication which is of benefit, we would not advise tapering off medication -- and subsequent risk of relapse -- in order to participate in the study. The same line of thinking applies to all psychiatric diagnoses and associated medications candidate subjects may be taking.

Exclusion Criteria:

1. Significant head trauma with loss of consciousness.
2. Active abuse of alcohol or illegal substances.
3. Excluded psychiatric diagnoses include: Bipolar Affective Disorder, primary psychotic disorders (Schizophrenia, Schizoaffective disorder), Obsessive-Compulsive Disorder.
4. Pregnant or nursing women.

5. Any contraindication to being scanned in the 3T scanner at the Lucas Center such as having a pacemaker.

   or any implanted device that has not been cleared for scanning at 3 Tesla.

6. Any significant neurologic history (i.e., seizure, stroke, multiple sclerosis).
7. Use of psychotropic medications within 2 weeks of enrollment.