The U.S. Department of Defense wants to limit troops to only three incidents of concussion, from roadside bombs, per combat tour. Troops that reach this limit, are given a non-combat job for the rest of their tour. But the marines have been using a similar policy, for over a year, in Afghanistan, and are satisfied with it. The marine criteria is more complex, taking into account all sources of concussion. However, most of the troops exposed to combat injury are army.
What spurred this idea is the discovery that physical injuries (to the brain) can now be detected (with more precise instruments like MRI), and often treated. In the last few years, it has become clear that there are several sources of PTSD (post-traumatic stress disorder), and concussions from explosions is more of a factor than previously thought. Many troops, because of exposure to roadside bombs, and battlefield explosions in general, have developed minor concussions that, like sports injuries, could turn into long term medical problems. Often these concussions were accompanied by some PTSD. Medical experts believe that the proposed policy would have long term benefits, in that it would prevent permanent brain injuries and PTSD, including cases that could require a soldier or marine to be retired early on medical disability.
Combat commanders, and many of the troops pulled out of combat, are opposed to the proposal. The commanders feel that sending units into action with fewer troops makes it more likely that they will suffer still more casualties. Infantrymen tend to be reluctant to leave their buddies in the lurch, unless physically unable to continue fighting. The military may change this by convincing troops that, like boxers, hockey or football players, too many concussions will lead to serious problems down the line, or even sooner.
Another problem with this proposal is that roadside bombs are only one of several sources of concussions. But the military medicine experts believe that roadside bombs are, by far, the biggest source of these concussions, and the resulting brain injuries. The proposed "three bombs and you're out" (of combat) rule, is not expected to pull more than one or two percent of troops out of action. But this would have a higher impact on combat units, which always suffer most of the casualties. Thus infantry units might lose another 5-10 percent of their troops.
U.S. combat troops are more frequently admitting to having "combat fatigue" (PTSD), mainly because they can now refer to at something other than a "mental condition." All this is the result of U.S. Department of Defense and the Veterans Administration (VA) efforts to document the connection between concussions, and other brain trauma, and PTSD conditions. There is a PTSD epidemic right now, created by the unprecedented exposure of so many troops, to so much combat, in so short a time.
The U.S. Army now mandates a mental health evaluation for everyone in the army. Those who have not been in combat, will serve as a baseline for comparing to those who have. Moreover, the army wants to find out to what extent non-combat operations (training can often be quite intense) can add to the stress that could eventually lead to PTSD. The basic idea here is to "mainstream" PTSD, trying to convince all the troops that PTSD is just another occupational hazard, not something you should try and hide, and hide from. You can't, and increasingly, the army won't let you. The records sharing recognizes that PTSD symptoms many not show up until years after the soldier has left the military. This is part of a broad trend in medicine, where better diagnostic tools enable diagnosing more people with problems that were largely ignored in the past.
In the last year, the army developed a new program to detect, and treat, the many PTSD sufferers it believes it has. This was accomplished by performing screening during the delivery of routine medical care, including annual checkups. Doctors are given a script that uses some simple and non-threatening questions to discover if the soldier might have PTSD. If further questioning reveals there may be some PTSD, the soldier is offered treatment as part of regular medical care, not a special PTSD program. It was those programs that put off many troops. While most troops now accept that PTSD is not a sign of mental weakness, but a very real combat hazard, many still avoid special PTSD treatment programs. By making PTSD treatment (which is usually just monitoring, and the use of some anti-stress medication for a while), part of regular medical care, much of the stigma disappears.
The army has, over the years, developed a set of guidelines for how to recognize the symptoms of combat fatigue (or PTSD). With all the attention PTSD has gotten in the media of late, troops are more willing to seek treatment, or at least admit there is a problem. While extreme cases of PTSD are pretty obvious, it's the more subtle ones that army wants to catch now. These are easier to cure if caught early.