The biggest longitudinal study of soldiers returning from Iraq, led by VA researcher Charles Milliken and published in 2007, seemed to confirm that we should expect a high incidence of PTSD. It surveyed combat troops immediately on return from deployment and again about six months later and found around 20 percent symptomatically "at risk" of PTSD. But of those reporting symptoms in the first survey, half had improved by the second survey, and many who first claimed few or no symptoms later reported serious symptoms. How many of the early "symptoms" were just normal adjustment? How many of the later symptoms were the imposition of a trauma narrative onto other problems?

[Major Matt] Stevens [who served in Iraq as a medic and experiences combat-related dreams], for one, is certain these screens are mistaking many going through normal adjustment as dangerously at risk of PTSD. Even he, though functioning fine at work and home and in society, scored positive in both surveys; he is, in other words, one of the 20 percent at risk. Finally, and weirdly, both screens missed about 75 percent of those who actually sought counseling a finding that raises further doubts about the evaluations' accuracy. Yet this study received prominent media coverage emphasizing that PTSD rates were probably being badly undercounted.

A few months later another study the first to track large numbers of soldiers through the wars in Iraq and Afghanistan provided a clearer and more consistent picture. Led by U.S. Navy researcher Tyler Smith and published in the British Medical Journal, the study monitored mental health and combat exposure in 50,000 U.S. soldiers from 2001 to 2006. The researchers took particular care to tie symptoms to types of combat exposure. Among some 12,000 troops who went to Iraq or Afghanistan, 4.3 percent developed diagnosis-level symptoms of PTSD. The rate ran about 8 percent in those with combat exposure and 2 percent in those not exposed.

These numbers are about a quarter of the rates Milliken found. But they are a close match to PTSD rates seen in British Iraq War vets and to rates [Richard] McNally [of the Harvard Department of Psychology] calculated for Vietnam veterans. The contrast to the Milliken study, along with the consistency with British rates and with McNally's NVVRS calculation, should have made the Smith study big news. Yet the media, the VA and the trauma psychology community almost completely ignored the study. "The silence," McNally wryly noted, "was deafening." [my emphasis]