by Bruce Sylvester: Ketamine reduced suicidal thoughts in a small group of patients with treatment-resistant depression, researchers reported on May 10, 2016 in the Journal of Clinical Psychiatry.
“Our finding that low doses of ketamine, when added on to current antidepressant medications, quickly decreased suicidal thinking in depressed patients is critically important because we don’t have many safe, effective, and easily available treatments for these patients,” said lead investigaor Dawn Ionescu, MD, of the Massachusetts General Hospital Department of Psychiatry, in Boston. “While several previous studies have shown that ketamine quickly decreases symptoms of depression in patients with treatment-resistant depression, many of them excluded patients with current suicidal thinking,” she added.
As background, the authors noted that the risk for suicide attempts is 20 times higher among patients with depression than in the general population. Medications used to treat suicidal thinking, including lithium and clozapine, often have serious side effects. And in prior studies, ketamine treatment has shown efficacy in rapid relief of symptoms of depression.
The investigators enrolled 14 subjects with moderate to severe treatment-resistant depression who had persistent suicidal thoughts for three months or more. Each subject received stable antidepressant treatment plus two weekly ketamine infusions over a three-week period. Initial dose was 0.5 mg/kg over a 45 minute period. After the first three dosings, it was raised to 0.75 mg/kg.
Assessments took place after about 4 hours after each infusion.
During the three-month follow-up phase (after the three-week infusion period ended), investigators assessed each subject every other week.
Assessments in both phases of the study included validated measures of suicidal thinking, in which subjects noted whether they had specific suicide-related thoughts, their frequency and intensity.
Twelve of the 14 subjects completed all treatment visits, most reported a decrease in suicidal thinking, and seven achieved complete remission of suicidal thoughts during active treatment. Of those seven, two maintained remission from both suicidal thinking and depression symptoms throughout follow-up.
Of those seven participants, two maintained remission from both suicidal thinking and depression symptoms throughout the follow-up period.
There were no serious adverse events at either dose.
Ionescu added, “In order to qualify for this study, patients had to have suicidal thinking for at least three months, along with persistent depression, so the fact that they experienced any reduction in suicidal thinking, let alone remission, is very exciting. We only studied intravenous ketamine, but this result opens the possibility for studying oral and intranasal doses, which may ease administration for patients in suicidal crises.”