Use of Ketamine to Enhance Electroconvulsive Therapy (ECT) in Depression

Inclusion Criteria: 1. Male or female patients: 18 to 59 years 2. Women of childbearing potential must agree to use a medically accepted means of contraception for the duration of the study 3. DSM IV MINI diagnosis of major depressive episode (MDD), unipolar or bipolar 4. Pretreatment 24-item Hamilton Rating Scale for Depression score \> 21 5. ECT is clinically indicated 6. Patient has the capacity to provide informed consent. Exclusion Criteria: 1. DSM-IV diagnosis of schizophrenia, schizoaffective disorder, or mental retardation 2. Current primary diagnosis of anxiety disorder, obsessive- compulsive disorder, or eating disorder that precedes the onset of the current episode of depression 3. Current diagnosis of delirium, dementia, or amnestic disorder 4. Baseline Mini Mental State Exam (MMSE) score \< 24 and a total score falling two standard deviations below the age- and education-adjusted mean 5. Any active general medical condition or CNS disease which can affect cognition or response to treatment 6. Current (within the past three months) diagnosis of active substance dependence, or active substance abuse within the past week 7. Lifetime history of ketamine or PCP abuse or dependence 8. ECT within three months 9. The presence of any known or suspected contraindication to methohexital or ketamine including but not limited to known allergic reactions to these agents, uncontrolled hypertension arrhythmia severe coronary artery disease and porphyria 10. Pregnancy