One dose of intravenous ketamine can provide significant and rapid relief for symptoms of major depressive disorder and PTSD when other treatments have failed. Researchers recently conducted a randomized controlled trial to determine the drug’s efficacy and safety for the treatment of PTSD when administered repeatedly over the course of two weeks. Thirty participants with chronic PTSD received six infusions of either intravenous ketamine or placebo over the study period. After two weeks, the ketamine group showed a significant reduction in symptom severity compared to the control group, without serious adverse effects. To learn more, see the study in the American Journal of Psychiatry.