Repeated ketamine infusions may reduce symptom severity in chronic PTSD
Repeated ketamine infusions appeared efficacious in reducing symptom severity among individuals with chronic PTSD, according to study results published in American Journal of Psychiatry.
“We embarked on this study in response to the critical need for the development of novel, effective interventions for the treatment of chronic PTSD, as currently available treatments do not work for a substantial number of individuals who suffer from this condition,” Adriana Feder, MD, of the department of psychiatry at Icahn School of Medicine at Mount Sinai, told Healio Psychiatry. “We decided to conduct this randomized controlled trial to evaluate the efficacy of a course of six intravenous ketamine infusions, administered over 2 consecutive weeks, encouraged by promising findings from our earlier proof-of-concept trial studying the efficacy of a single ketamine infusion for chronic PTSD.”
Feder and colleagues randomly assigned 30 individuals with chronic PTSD 1:1 to six infusions of 0.5 mg/kg of ketamine or 0.045 mg/kg of midazolam, which served as the psychoactive placebo control, across 2 consecutive weeks. Further, they administered clinician-rated and self-report assessments 24 hours after the first infusion, as well as at weekly visits. Change in PTSD symptom severity according to the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5) from baseline to 2 weeks, served as the primary outcome. The Impact of Event Scale-Revised, the Montgomery-Åsberg Depression Rating Scale (MADRS) and side effect measures served as secondary outcome measures.
Results showed a significantly greater improvement in CAPS-5 and MADRS total scores among the ketamine group vs. the midazolam group from baseline to 2 weeks. The mean CAPS-5 total score at 2 weeks was 11.88 points lower among the ketamine groups vs. the midazolam group. A total of 67% of those in the ketamine group were treatment responders, vs. 20% in the midazolam group. The median time to loss of response among ketamine responders was 27.5 days after the 2-week course of infusions. Participants did not exhibit serious adverse events, and ketamine infusions appeared well tolerated overall.
“This is the first evidence from a randomized controlled trial that a course of repeated ketamine infusions can result in rapid and clinically significant improvement in PTSD symptoms in individuals with chronic PTSD, even if they have had this condition for over a decade or longer,” Feder said. “In our study, two-thirds of individuals in the ketamine group improved significantly, and their symptoms remained improved on average for several weeks. These findings represent a significant step forward in the development of ketamine as a viable treatment for this condition."