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.