Repeated intravenous (IV) ketamine infusions significantly reduce symptom severity in individuals with chronic post-traumatic stress disorder (PTSD) and the improvement is rapid and maintained for several weeks afterwards, according to a study conducted by researchers from the Icahn School of Medicine at Mount Sinai. The study, published September XX in the American Journal of Psychiatry, is the first randomized, controlled trial of repeated ketamine administration for chronic PTSD and suggests this may be a promising treatment for PTSD patients.