A single intravenous infusion of ketamine produced greater improvement in depression severity 24 hours later than the active placebo midazolam in patients with treatment-resistant major depression. In a randomized controlled trial of 73 participants, the ketamine group scored 7.95 points lower on the Montgomery-Åsberg Depression Rating Scale than the midazolam group. Response rates were 64% for ketamine and 28% for midazolam, with an odds ratio of 2.18 favoring ketamine. The findings support NMDA receptor modulation as a mechanism for rapid improvement in severe, chronic depression, though more information on durability and safety is needed before clinical use.
A single intravenous dose of ketamine (0.5 mg/kg) rapidly reduced posttraumatic stress disorder (PTSD) symptom severity more than the active placebo midazolam in patients with chronic PTSD. Twenty-four hours after infusion, the ketamine group showed a mean reduction of 12.7 points on the Impact of Event Scale-Revised compared to midazolam. Ketamine also lessened comorbid depressive symptoms and improved overall clinical presentation. The treatment was generally well tolerated without persistent dissociative symptoms. These results suggest ketamine may offer a novel pharmacologic approach for chronic PTSD, though replication is needed.