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.
A single infusion of ketamine, compared to midazolam as an active placebo, did not reduce suicidal ideation scores on the Beck Scale for Suicidal Ideation at 24 hours in patients with mood and anxiety disorders who were at elevated risk for suicidal behavior. A significant difference favoring ketamine emerged at 48 hours, but the effect was no longer significant by the end of 7 days. The intervention was well tolerated with no dropouts during the primary assessment period. The findings support the safety and tolerability of ketamine for suicidal ideation but larger studies are needed.
Ketamine given intravenously at 0.5 mg/kg over 40 minutes was safe and well tolerated in a large group of patients with treatment-resistant depression. Across 205 infusions in 97 participants, the antidepressant response rate was 67%. Only about 2% of infusions were stopped due to adverse effects, and the overall dropout rate was 3%. Common temporary side effects in the first four hours included drowsiness, dizziness, poor coordination, blurred vision, and feeling strange or unreal. About one third of participants had changes in blood pressure or heart rate. There were small but significant increases in psychotomimetic and dissociative symptoms, but no lasting psychotic effects, medical complications, or increased substance use among those followed long-term.