Opiate Suicide Study in Patients With Major Depression

The investigators hypothesize that patients who receive buprenorphine following ketamine will demonstrate significantly greater anti-suicidal effects over the course of the study and maintained until four weeks of buprenorphine than will placebo. Buprenorphine subjects will also demonstrate longer times to recurrence than will those who receive ketamine followed by placebo. As secondary analyses, the investigators will test whether there is a relationship of improvement in sleep and pain to change in suicide ratings. Aim 2: To assess the potential role played by the opioid properties of a single infusion of ketamine, investigators will for the ketamine portion determine ketamine and metabolite blood levels during and after the infusion as well as pupillary changes and correlate them to anti-suicidal response at Day 1. Investigators will also collect blood to determine buprenorphine blood levels, prolactin as well as collecting data on pupillary changes and then assess for potential relationships with anti-suicidal response.