Ketamine-Assisted Psychotherapy for Treatment-Resistant Depression

Inclusion Criteria The following inclusion criteria must be met for all subjects to be considered eligible to participate: 1. 18 years old or older 2. Able to speak, read, and understand English 3. In generally stable health 4. Must have treatment resistant depression, as defined as scoring in the moderate or above range on the HDRS and having failed two adequate trials of antidepressants in the last two years. Exclusion Criteria General exclusion criteria for all subjects include: 1. Uncontrolled hypertension 2. Impaired cardiac status a. Abnormal ECG report in the last month prior to screening 3. Chronic Obstructive Pulmonary Disease 4. Congenital Long QT Syndrome 5. ≥265lbs or 120kg 6. Severe obesity (BMI ≥40) 7. Increased intracranial or cerebrospinal pressure 8. Pregnancy or breastfeeding 9. Hyperthyroidism 10. Prior adverse response to ketamine, including allergic reaction 11. Symptoms of psychosis or prodromal phase 12. Severe personality disorder 13. Autistic Spectrum Disorders 14. Bipolar disorder 15. History of substance abuse, defined as a score of three or more on Drug Abuse scale (prior use of psychedelics allowed) 16. Past-year suicide attempt or ongoing ideation with intent to act 17. All exclusion criteria for magnetic resonance imaging safety: any metallic implants, brain or skull abnormalities, tattoos on large body parts, and claustrophobia. 18. Taking medications that could interact with ketamine. Examples include but are not limited to: any types of stimulants, aripiprazole, diphenhydramine, hydromorphone, escitalopram, fluoxetine, alprazolam, and sertraline. Each subject's current medications will be evaluated for interactions with ketamine before admission into the trial.