IV Ketamine Not a 'Silver Bullet' for Depression, but Does Help Some

FRIDAY, Feb. 9, 2024 (HealthDay News) -- Nearly half of Veterans Health Administration (VA) patients with treatment-resistant depression who received intravenous (IV) ketamine saw a meaningful drop in depression scores by the end of six weeks of infusions, according to a study published online Jan. 8 in The Journal of Clinical Psychiatry.

Paul N. Pfeiffer, M.D., from the University of Michigan Medical School in Ann Arbor, and colleagues used data from the VA electronic medical records for 215 patients treated with IV ketamine infusions for depression in fiscal year 2020, with up to 12 months of follow-up.

The researchers found that participants had a mean of 2.1 antidepressant medication trials in the past year and 6.1 antidepressant trials in the 20 years prior to their first ketamine infusion. During the first five months of infusions, frequency of infusions decreased from every five days to every three to four weeks, with a mean of 18 total infusions over 12 months. After six weeks of treatment, 26 percent of participants had a response (50 percent improvement in the Patient Health Questionnaire-9 [PHQ-9] score) and 15 percent had remission (PHQ-9 score ≤5). At weeks 12 and 26, these improvements were similar. There were no associations between demographic characteristics and comorbid diagnoses with six-week PHQ-9 scores.

"These findings ratchet down the hype about ketamine a bit, because we don’t see dramatic improvement after just one infusion, or strong response in most patients," Pfeiffer said in a statement. "It's not a silver bullet. But when we see these patients in our clinic, who have been through every treatment available and nothing has worked, to have even a quarter achieve a significant measurable response is very good."

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