A review of existing literature on ketamine use in people with dementia found only three case reports. One case used subcutaneous ketamine for depression, one used intramuscular ketamine for acute agitation, and one used S-ketamine as anesthesia during electroconvulsive therapy for depression and catatonia. No significant adverse effects were reported. The evidence remains limited, and high-quality prospective studies are needed before ketamine can be used to treat behavioral disturbances in dementia.
In an open-label clinical trial, a single intravenous infusion of ketamine (0.5 mg/kg) was safe and well tolerated in 13 patients with mild cognitive impairment and major depressive disorder. No serious adverse events occurred. Depression severity, measured by the Montgomery-Asberg Depression Rating Scale, dropped from a mean of 27.4 before treatment to 5.7 at 24 hours after the infusion—a large-magnitude improvement. For 8 of the 13 patients, this improvement persisted for up to one month, with a mean score of 12.1 and at least a 50% reduction. These findings suggest ketamine may be effective for depression in this population, but larger randomized controlled trials are needed to confirm efficacy and assess cognitive effects.