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A new study published in the American Journal of Psychiatry looked at repeated Ketamine administration for chronic post-traumatic stress disorder (PTSD).

“This study was the first randomized controlled trial to examine the efficacy of repeated ketamine infusions in improving PTSD symptoms in individuals suffering with chronic PTSD,” study author Adriana Feder told us. “We had conducted an earlier proof-of-concept trial of a single ketamine infusion in patients with this condition. Based on our initial findings from that study, we wanted to see whether a course of repeated ketamine infusions would result in similarly rapid PTSD symptom improvement, and would additionally maintain symptom improvement for a longer period of time in patients with this condition.”

Researchers hypothesized that a course of repeated ketamine infusions would result in rapid symptom improvement when administered to individuals with PTSD, and that this improvement would be maintained for a longer period of time.

“Many individuals with chronic PTSD do not get better with currently available treatments, or improve only partially, or have difficulty tolerating these treatments,” Feder told us. “Given this clear need for new treatments for this disabling condition, several years ago we started studying ketamine as a potential new treatment for this condition.”

According to the Recovery Village, 70% of adults experience at least one traumatic event in their lifetime. Twenty per cent of people who experience a traumatic event will develop PTSD. About eight million people have PTSD annually, and 1 in 13 people will develop PTSD at some point in their life.
Researchers conducted a double-blind randomized control trial, in which half of the study participants were randomly assigned to receive six ketamine infusions and the other half six infusions of the psychoactive placebo control midazolam, administered over two consecutive weeks. All participants had chronic PTSD which had lasted 15 years on average.

Two-thirds of participants in the ketamine group showed a rapid and robust improvement in PTSD symptoms, compared to only 20% of participants who received midazolam infusions. Symptom improvement on average persisted for several weeks, and was accompanied by improvement in depressive symptoms, which are also often present alongside PTSD symptoms.

“Based on our earlier study of a single infusion of ketamine (compared to midazolam) for chronic PTSD, we had anticipated positive results from this new study, but were surprised by the robustness of the clinical response, and heartened to see that those who felt improved continued to feel better for several weeks,” Feder told us. “PTSD is often chronic and can greatly impact a person’s ability to function in life. Currently approved treatments for PTSD can take weeks or months to work, and they don’t work or work only partially for a substantial proportion of individuals who seek treatment.”

Feder believes results from this new study are very encouraging, as they show that ketamine infusions can rapidly treat PTSD symptoms in many individuals with chronic PTSD, and that repeated infusions can maintain this improvement for longer.

“Going forward, we and others plan to evaluate interventions that can potentially maintain improvement over longer periods of time –for example administering additional infusions after the initial course of six, perhaps further spaced out over time, or adding a brief, trauma-focused psychotherapy to a course of six infusions to see if these approaches can maintain the initial response to ketamine over time.”