Xenon gas, normally used for anesthesia or diagnostic imaging, may treat post-traumatic stress disorder (PTSD), according to new research from McLean Hospital in Belmont, Mass.

In a study published in PLOS ONE, researchers analyzed whether a low concentration of xenon gas could interfere with the process by which reactivated memories become susceptible to modification, called reconsolidation. PTSD is characterized by re-experiencing of traumatic memories, including flashbacks, nightmares, and distress and physiological reactions induced when confronted with trauma reminders.

"We know from previous research that each time an emotional memory is recalled, the brain actually restores it as if it were a new memory,” Edward G. Meloni, assistant professor at McLean Hospital and an assistant professor of psychiatry at Harvard Medical School said in a press release. “With this knowledge, we decided to see whether we could alter the process by introducing xenon gas immediately after a fear memory was reactivated.”

Using an animal model of PTSD called fear-conditioning, researchers found that a single exposure to the gas dramatically reduced negative responses to fearful memories. For up to two weeks after the test, the mice seemed to no longer remember to be afraid of the fear-inducing environmental cues.

Researchers noted that the inherent properties of a gas such as xenon make it especially attractive for targeting dynamic processes such as memory reconsolidation. Xenon goes in and out of the brain very quickly, suggesting it could be administered at the exact time a memory is reactivated, and for a limited amount of time— key features for potential therapy for humans.

"The fact that we were able to inhibit remembering of a traumatic memory with xenon is very promising because it is currently used in humans for other purposes, and thus it could be repurposed to treat PTSD," Marc J. Kaufman, director of the McLean Hospital Translational Imaging Laboratory said in a press release.

Further testing is needed to address issues such as dosage amounts and times, and whether the findings translate to humans.

"In our study, we found that xenon gas has the capability of reducing memories of traumatic events," Meloni said. "It's an exciting breakthrough, as this has the potential to be a new treatment for individuals suffering from PTSD."