N-methyl-D-aspartate Antagonist (Ketamine) Augmentation of Electroconvulsive Treatment for Severe Major Depression

Inclusion Criteria: 1. males and females between the ages of 18-65, 2. DSM-IV diagnosis of Major Depressive Disorder (MDD), without psychotic features 3. HAM-D-28 score of 20 or higher 4. requiring ECT treatment as part of their psychiatric care Comorbid anxiety disorders (OCD, Generalized anxiety, panic disorder) will be allowed as long as the clinician administering the SCID believes that they are not the primary diagnosis. Exclusion Criteria: 1. MDD with a score of \<20 on the HAM-D 28, 2. Other DSM-IV primary diagnoses including major depressive disorder with psychotic features, bipolar disorder, schizoaffective disorder, schizophrenia, dementia 3. any history of psychosis 4. substance use disorder (abuse or dependence with active use within the last 6 months), and any lifetime history of ketamine abuse or dependence; 5. organic mental disorders; 6. seizure disorder or chronic antiepileptic medications; 7. severe or unstable medical illness, including history of closed head injury resulting in loss of consciousness, medical contraindication to anesthesia or to ECT (i.e. recent myocardial infarction, increased intracranial pressure) 8. current treatment with memantine 9. pregnancy, or females of reproductive age who are not using an accepted method of contraception (birth control pill, IUD, combination of barrier methods). 10. known hypersensitivity to ketamine