Using a placebo-controlled, multi-centre, double-blinded design, the current pair of studies examined the immediate antidepressant efficacy of ketamine in 76 patients with treatment-resistant major depression. All treatments were served as a single intravenous infusion over a 1 h period, and then patients were taken home and monitored for 24 h for emergence of adverse events (AEs) or clinical worsening of depression scores. The primary efficacy outcome was change from baseline on the MADRS total score during a 14 day treatment window following completion of the 3 treatments within each study. There was no significant difference between ketamine and placebo in response rates at week 1!!