Repeated ketamine infusions ease PTSD symptoms

Repeated ketamine administration is effective in the reduction of symptom severity in individuals with chronic post-traumatic stress disorder (PTSD), suggests a study.

The authors randomized 30 individuals with chronic PTSD to receive six infusions of either ketamine (0.5 mg/kg) or midazolam (0.045 mg/kg; psychoactive placebo control) over 2 consecutive weeks. Clinician-rated and self-report assessments were administered 24 hours after the first infusion and at weekly visits.

Change in PTSD symptom severity, assessed with the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5) from baseline to 2 weeks (after completion of all infusions), was the primary outcome. Secondary ones included the Impact of Event Scale–Revised, the Montgomery-Åsberg Depression Rating Scale (MADRS), and side effects measures.

From baseline to week 2, patients on repeated ketamine infusions had a significantly greater improvement in CAPS-5 and MADRS total scores than those on midazolam. The mean CAPS-5 total score was 11.88 points lower in the ketamine group than in the midazolam group (d, 1.13, 95 percent confidence interval, 0.36–1.91) at week 2.

Significantly more participants in the ketamine group were treatment responders compared to the those in the midazolam group (67 percent vs 20 percent). Among ketamine responders, the median time to loss of response was 27.5 days following the 2-week course of infusions.

Overall, ketamine infusions were well tolerated, with no serious adverse events reported.

“Further studies are warranted to understand ketamine’s full potential as a treatment for chronic PTSD,” the authors said.

In previous proof-of-concept randomized controlled trial of single-dose intravenous ketamine infusion, individuals with PTSD demonstrated significant and swift reduction in PTSD symptoms 24 hours postinfusion.