Intranasal Ketamine in Treatment-Resistant Depression

Inclusion Criteria: 1. Male or female patients, 21-65 years; 2. Women of childbearing potential must agree to use a medically accepted means of contraception for the duration of the study; 3. Primary diagnosis of major depressive disorder as assessed by the SCID-P; 4. Current depressive episode; 5. History of a failure to respond to at least one (1) adequate pharmacotherapy trials in the current major depressive episode; 6. Subjects must have scored ≥ 30 on the IDS-C30 at Screening ≥ 24 at Treatment Day #1 and #2; 7. Each subject must have a level of understanding sufficient to agree to all tests and examinations required by the protocol and must sign an informed consent document; 8. Subjects must be able to identify a family member, physician, or friend who will participate in the Treatment Contract and serve as an emergency contact. Exclusion Criteria: 1. Women who plan to become pregnant, are pregnant or are breast-feeding; 2. Any unstable medical illness including hepatic, renal, gastroenterologic, respiratory, cardiovascular, endocrinologic, neurologic, immunologic, or hematologic disease; 3. Clinically significant abnormal findings of laboratory parameters, physical examination, or ECG; 4. Lifetime history of schizophrenia, schizoaffective disorder, bipolar disorder, OCD, mental retardation, pervasive developmental disorders, or Tourette's syndrome; 5. Drug or alcohol abuse or dependence within the preceding 6 months; 6. Lifetime abuse or dependence on ketamine or phencyclidine; 7. Patients judged by study investigator to be at high risk for suicide. 8. Previous participation in a ketamine study at Mount Sinai