Day 18: (visit 3) assessments will include psychiatric ratings (including Hamilton Depression Rating Scale and Clinician's Global Impression). Adverse events and concomitant medications will be reviewed and recorded. Clinical laboratory assessments will be completed (including a urine pregnancy test for females, comprehensive metabolic panel, comprehensive blood count, urine toxicology, and ECG.) Final visit: (visit 4) will occur 24-72 hours after the last ECT treatment. 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. A urine pregnancy test will be completed for females.