Search for biological markers for PTSD

NY Times   Over the past decade, about half a million veterans have received diagnoses of post-traumatic stress disorder or traumatic brain injury. Thousands have received both. Yet underlying the growing numbers lies a disconcerting question: How many of those diagnoses are definitive? And how many more have been missed? 

No one can say. Though PTSD is hardly new, diagnoses still largely rely on self-reported symptoms. And while severe brain injuries are often clearly diagnosable, finding evidence of mild T.B.I.’s, particularly older ones, can be all but impossible. [...]

Dr. Marmar faces deep skepticism that biological signals can be found for psychiatric disorders like PTSD or depression, which his group is also studying, or even a less severe brain injury.

But while previous quests have failed to produce results that could be replicated, private foundations and the government still seem willing to finance new efforts, amid the growing tally of disabled veterans.