Ketamine For Suicidal Ideation

Inclusion Criteria:

* English speaking Male or female patients, 18-80 years
* Patients have voluntarily admitted themselves to an inpatient psychiatric unit at MSH or, regarding the outpatient population, have clinically significant suicidal ideation without intent to harm themselves
* Women of childbearing potential must have a negative pregnancy test
* Clinically significant suicidal ideation and score of ≥4 on MADRS item 10 for suicidality
* 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

Exclusion Criteria:

* Lifetime history of schizophrenia or other primary psychotic disorder
* Current presence of psychotic symptoms
* Lifetime history of a clearly established psychotic episode
* Established diagnosis of Schizoid, Schizotypal or Paranoid personality disorder
* Urine toxicology screen positive for drugs of abuse on admission
* Substance abuse or dependence within the preceding 1 month
* Anticipated discharge within 7 days of study enrollment (for patients in the inpatient arm)
* Women who plan to become pregnant, are pregnant or are breast-feeding
* Concurrent course of electroconvulsive therapy (ECT)
* Any unstable medical illness including hepatic, renal, gastro-enterologic, respiratory, cardiovascular, endocrinologic, neurologic, immunologic, or hematologic disease
* Clinically significant abnormal findings of laboratory parameters, physical examination, or ECG
* The presence of any known or suspected contraindications to midazolam or ketamine including, but not limited to, known allergic reactions to these agents or acute intermittent porphyria
* Uncontrolled hypertension, defined as BP systolic \>160 or BP diastolic \>100 on medications
* Arrhythmia requiring medication
* Severe coronary artery disease, defined as Canadian Cardiovascular Status III or IV