NIMH researchers studied the effects of a single dose of ketamine in depressed patients with bipolar depression and found:
When the patients received ketamine, their depression symptoms significantly improved within 40 minutes, and remained improved over 3 days. Overall, 79% of the patients improved with ketamine, but 0% reported improvement when they received placebo.
Importantly, and for the first time in a group of patients with bipolar depression, they also found that ketamine significantly reduced suicidal thoughts. These antisuicidal effects also occurred within one hour…
“Our finding that a single infusion of ketamine produces rapid antidepressant and antisuicidal effects within one hour and that is fairly sustained is truly exciting,” Dr. Zarate commented. “We think that these findings are of true importance given that we only have a few treatments approved for acute bipolar depression, and none of them have this rapid onset of action; they usually take weeks or longer to have comparable antidepressant effects as ketamine does.”