The study showed that ketamine acutely reduced suicidal thoughts when patients were assessed 24 hours after a single infusion.
This reduction in suicidality was maintained when patients received repeated doses over the next two weeks.
Corresponding author Rebecca Price called the findings encouraging.
"If these findings hold up in larger samples of high-risk suicidal patients, IV ketamine could prove an attractive treatment option in situations where waiting for a conventional antidepressant treatment to take effect might endanger the patient's life," she said.
However, since this was a preliminary study in a small group of depressed patients, researchers said further research is needed to replicate these results.
The results were published in Biological Psychiatry. (ANI)