A preliminary study by researchers at the National Institute of Mental Health has found that a single intravenous dose of ketamine can provide symptom relief for some individuals with treatment-resistant depression (Zarate ZA et al. Arch Gen Psychiatry. 2006;63:856-864).
In the randomized, placebo-controlled, double-blind crossover study, 18 treatment-resistant depressed patients were assigned to receive either a single intravenous dose of ketamine or placebo. Ketamine improved depression symptoms within 1 day in 71% of patients receiving the drug, and 29% of these were nearly symptom-free.
Hampton T. Ketamine for Depression. JAMA. 2006;296(12):1458. doi:10.1001/jama.296.12.1458-a