In the new study, researchers at the Naval Health Research Center in San Diego reviewed detailed medical records of 696 troops who had been wounded in Iraq between 2004 and 2006, determining whether and when morphine was used in treatment. Military doctors used the drug for most serious injuries — generally in the first two hours after the injury — but sometimes administered others, like anti-anxiety medications.
The study found that 243 of the servicemen and women were given a diagnosis of post-traumatic stress within two years of their injury. When the severity of the wounds was taken into account, researchers calculated that the diagnosis was half as common in those who had received morphine as in those who had not.
Age, sex and the cause of injury did not significantly alter the findings, said Troy Lisa Holbrook, the study’s lead author. “This is just one paper, one analysis, but it’s exciting because of the strength of the finding,” Dr. Holbrook said. “A lot of people have been looking for a secondary preventive to interrupt the formation of traumatic memories.”
…The drugs appear to blunt the emotional charge of traumatic memories in several ways. Most obviously, they kill the pain when it is most excruciating; often, they scramble the ability to recall what exactly happened. Opiates also inhibit the production of a chemical messenger called norepinephrine, which is thought to enhance fear signals in the brain.
This is a pretty big deal if it holds up in future trials. One caveat I’ve not had time to check out is whether the morphine was often applied as part of an more robust medical response in general, which itself might reduce later PTSD symptoms. I hope the DOD soon follows up with another, larger study, for as Ben Carey notes, the has some substantial implications if indeed it holds up.