Ketamine was significantly more effective than a commonly used sedative in reducing suicidal thoughts in depressed patients, according to researchers at Columbia University Medical Center (CUMC). They also found that ketamine's anti-suicidal effects occurred within hours after its administration.
The findings were published online last week in the American Journal of Psychiatry.
According to the Centers for Disease Control and Prevention, suicide rates in the U.S. increased by 26.5 percent between 1999 and 2015.
"There is a critical window in which depressed patients who are suicidal need rapid relief to prevent self-harm," said Michael Grunebaum, MD, a research psychiatrist at CUMC, who led the study. "Currently available antidepressants can be effective in reducing suicidal thoughts in patients with depression, but they can take weeks to have an effect. Suicidal, depressed patients need treatments that are rapidly effective in reducing suicidal thoughts when they are at highest risk. Currently, there is no such treatment for rapid relief of suicidal thoughts in depressed patients."
Most antidepressant trials have excluded patients with suicidal thoughts and behavior, limiting data on the effectiveness of antidepressants in this population. However, previous studies have shown that low doses of ketamine, an anesthetic drug, causes a rapid reduction in depression symptoms and may be accompanied by a decrease in suicidal thoughts.
The 80 depressed adults with clinically significant suicidal thoughts who enrolled in this study were randomly assigned to receive an infusion of low-dose ketamine or midazolam, a sedative. Within 24 hours, the ketamine group had a clinically significant reduction in suicidal thoughts that was greater than with the midazolam group. The improvement in suicidal thoughts and depression in the ketamine group appeared to persist for up to six weeks.
Those in the ketamine group also had greater improvement in overall mood, depression, and fatigue compared with the midazolam group. Ketamine's effect on depression accounted for approximately one-third of its effect on suicidal thoughts, suggesting the treatment has a specific anti-suicidal effect.
Side effects, mainly dissociation (feeling spacey) and an increase in blood pressure during the infusion, were mild to moderate and typically resolved within minutes to hours after receiving ketamine.
"This study shows that ketamine offers promise as a rapidly acting treatment for reducing suicidal thoughts in patients with depression," said Dr. Grunebaum. "Additional research to evaluate ketamine's antidepressant and anti-suicidal effects may pave the way for the development of new antidepressant medications that are faster acting and have the potential to help individuals who do not respond to currently available treatments."