Post-traumatic stress is estimated to afflict more than 300,000 veterans of Iraq and Afghanistan, but until now, it's been labeled a "soft disorder" – one without an objective biological path to diagnosis. That may have changed this week, after researchers at the University of Minnesota and the Minneapolis VA Medical Center announced they'd found a distinct pattern of brain activity among PTSD sufferers.

The team used a brain imaging method called magnetoencephalography (MEG), which measures how the brain processes information. They scanned the brains of 74 U.S. veterans with PTSD, and 250 civilians without the disorder. By spotting specific brain biomarkers, they said they0 managed to accurately diagnose PTSD sufferers with 90 percent accuracy.

MEG machines are a fast, sensitive and accurate way to measure electric activity in the brain. Whereas CT scans and MRIs record brain signals every few seconds, MEGs can do it by the millisecond, catching biomarkers and brain activity that the other tests inevitably miss.

The study could be a breakthrough for the military, who've been scrambling to address a surge in post-traumatic symptoms among newly returning vets. Right now, troops are evaluated by mental health experts, but diagnosis is a crap-shoot: Symptoms can take years to show up, and vary from person to person, even among those exposed to the same traumas. The Pentagon has pushed for more objective, systematized diagnosis tools, like portable at-home sleep monitors and genetic testing to detect PTSD vulnerability. They've even launched a program to create stress-mitigating pharmaceuticals.

Of course, a study on 74 vets is only a start. Next up, the researchers want to evaluate 500 vets, alongside 500 civilians, to further validate their findings. And since PTSD is a complex disease, with new causes, symptoms and potential treatments popping up every week, it's hard to see how one set of biomarkers could pump out a definitive diagnosis for every tested veteran. Some PTSD symptoms, like depression and anxiety, are also highly personal – pretty tough to reduce to a single scan and an objective diagnosis.

Then there's the potential for the scans to impact how medical care is doled out and paid for. Dr. Apostolos Georgopoulos, the lead researcher on the discovery, hopes the breakthrough will speed treatment and simplify insurance coverage. But unless the scans are subjected to major clinical scrutiny, PTSD treatment to those whose MEG scans match a set of biomarkers might mean some ailing vets slip through the cracks – a grim picture that's already a reality.

Photo: U.S. ARMY

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