Morphine prevents PTSD! or does it?

Interesting headlines in clinical neuroscience. It looks like a shot of morphine after injury is correlated with slightly lower risks of developing post-traumatic stress disorder. But despite the promising headline’s like:

Morphine found to help stave off PTSD in wounded troops

Morphine shows promise against post-traumatic stress disorder

and intriguing speculation about the neurochemistry involved:

It is not known whether morphine’s apparently protective effect arises directly from the relief of traumatic pain or indirectly by blocking the brain circuits that lay down traumatic memory.

the actual study results don’t actually seem that impressive to me:

In the new study, Holbrook and her colleagues looked at the records of 696 wounded forces. About 40 percent had been injured by improvised explosive devices, generally roadside bombs; about 20 percent by gunshots and 10 percent by mortar rounds. About 70 percent received morphine within an hour of being hurt.

Most people developed PTSD, diagnosed from one month to two years after their injuries occurred. Those who had received morphine, however, were somewhat less likely. Sixty-one percent had the disorder, compared with 76 percent of people who hadn’t gotten the drug — which researchers said translated into a 53 percent reduction in risk.

I’m up too late to try working backwards to figure out how they calculated the percent reduction in risk, but if 76% of people get PTSD without morphine, and 61% of people get it with morphine, aren’t we talking about 15% fewer people in the patient population getting PTSD?

Overall, this is a very strange study to choose to write up in medical news, since, as the Washington Post article mentions, the science would have to be much, much better to make morphine shot a routine post-traumatic procedure (though it doesn’t mention why. My intuition is that it might have something to do with the fact that morphine addiction has historically been, and continues to be, a serious problem among veterans.

(Quotes taken from David Brown’s Washington Post article, linked above.)

[Via http://ptsdinthemedia.wordpress.com]