Ketamine for Treatment Resistant Late-Life Depression

Inclusion Criteria

• Male or female patients, 55 years of age,
• Participants must fulfill DSM 5 criteria for a Major Depressive Episode (Unipolar), based on a structured diagnostic interview, the DSM 5 M.I.N.I. 7.0
• Participants must have a history of at least one previous episode of depression prior to the current episode (recurrent MDD) or have chronic MDD (of at least two years' duration),
• Participants have not responded to two or more adequate trials of FDA-approved antidepressants, determined by Antidepressant Treatment Response Questionnaire (ATRQ) criteria.
• Participants must score 14 or greater on the Quick Inventory of Depressive Symptomatology-Self Report (QIDS-SR), and score 27 on the Montgomery Asberg Depression Rating Scale (MADRS),
• Each participant 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.

Exclusion Criteria

• Patients currently on fluoxetine,
• History of schizophrenia, schizoaffective disorder or any psychotic disorder, or bipolar disorder,
• Documented history of a psychotic disorder in a first-degree relative,
• Current diagnosis of obsessive-compulsive disorder (OCD) or eating disorder [bulimia nervosa or anorexia nervosa],
• Alcohol or substance use [except nicotine] within the preceding 6 months,
• Patients with any clinically significant personality disorder that would, in the investigator's judgment, preclude safe study participation,
• Patients judged to be at serious and imminent suicidal or homicidal risk,
• Serious, unstable medical illnesses including respiratory [obstructive sleep apnea, or history of difficulty with airway management during previous anesthetics], cardiovascular [including ischemic heart disease and uncontrolled hypertension], and neurologic [including history of severe head injury],
• For study entry, patients must be reasonable medical candidates for ketamine or midazolam infusion, as determined by a board-certified physician co-investigator during study Screening,
• Clinically significant abnormal findings of laboratory parameters [including urine toxicology screen for drugs of abuse], physical examination, or ECG,
• Hypertension (systolic BP >160 mm Hg or diastolic BP >90 mm Hg),
• Patients with one or more 11 seizures without a clear and resolved etiology,
• Patients starting hormonal treatment (e.g., estrogen) in the 3 months prior to Screening,
• Past intolerance or hypersensitivity to ketamine, or history of recreational use of phencyclidine (PCP) or ketamine,
• Past intolerance or hypersensitivity to midazolam,
• Age-related cognitive decline or mild dementia suggested by a score of 25% decrease in depressive symptoms as reflected by the QIDS-SR score from Screening to Randomization,
• Patients who have received electroconvulsive therapy (ECT) in the past 6 months prior to Screening,
• Patients currently receiving treatment with vagus nerve stimulation (VNS) or repetitive transcranial stimulation (rTMS).