Open-label trial · 2026
Single ketamine infusion in 13 older adults with depression and mild memory loss
- Original title
- KET-MCI: A Pilot Safety and Tolerability Study of Single Infusion Intravenous Ketamine for Older Adults with Depression and Mild Cognitive Impairment.
- Authors
- Fremont R, Karim A, Estevez TP, et al.
- Journal
- The American journal of geriatric psychiatry : official journal of the American Association for Geriatric Psychiatry, 2026
- Molecules
- Ketamine
- Conditions
- Depression, Other
- Participants
- 13
- Evidence grade
- Very low
- Source
- Read the original paper
The question
Is a single intravenous dose of ketamine safe and tolerable for older adults who have both major depression and mild cognitive impairment? The study also took a first look at whether depression scores changed.
What they did
Between November 2023 and March 2025, researchers enrolled patients who had mild cognitive impairment (early memory and thinking problems that fall short of dementia) alongside major depressive disorder with moderate to severe symptoms. Each person received one intravenous ketamine infusion at 0.5 mg/kg. Safety and tolerability were the main focus. Depression was measured with the Montgomery-Asberg Depression Rating Scale (MADRS) before the infusion and 24 hours afterward. Everyone knew what they were receiving; there was no placebo comparison.
What they found
Thirteen patients received the infusion and completed all study procedures. No serious adverse events were reported, and all participants tolerated the procedures. Average depression scores fell from 27.4 (standard deviation 6.4) at baseline to 5.7 (standard deviation 4.7) at 24 hours, with improvement seen in all patients. Eight individuals still showed at least a 50% improvement one month later, with an average MADRS of 12.1 (standard deviation 6.9).
The fine print
Only 13 people took part, and there was no placebo or comparison group, so the large drop in depression scores cannot be attributed to ketamine alone. Everyone knew they were receiving active treatment, which can inflate reported improvement. Follow-up ran to one month and only some participants maintained gains; effects on memory and thinking were not reported here. This summary is based on the published abstract only.
What it means
In this small first-step study, a single ketamine infusion was tolerated by older adults with depression and early cognitive problems, and depression scores dropped sharply. Larger randomized trials are needed before any conclusion about how well it works, or how it affects thinking, in this group.
Evidence grade: Very low. A small open-label pilot with 13 people, no placebo group and no comparison arm, so results cannot be separated from expectation effects.
This summary is based on the study’s published abstract.