Day 11: (visit 2) assessments will include psychiatric ratings (including Hamilton Depression Rating Scale and Clinician's Global Impression) and a battery of neuropsychiatric assessments. Adverse events and concomitant medications will be reviewed and recorded. Subjects will be admitted to the GCRC for collection of blood samples to measure ACTH and cortisol levels. Samples will be collected hourly beginning at 1pm and ending at 4pm.