current event post: US Soldier kills Afghan civilians

This was topic I had recently posted about but now that more details have emerged I would like to revisit this issue. So the reports are that this soldier who killed 16 unarmed Afghan civilians mostly women and children, was suffering from sever battle fatigue. To make matters worse his company witnessed a brutal attack on one of their fellow soldiers which may have been the breaking point for the suspected soldier who killed the civilians. This soldier was on his fourth Afghan tour wile also have a number of tours in Iraq. My question is should there be a limit on soldiers and the amount of combat tours they can have in a certain amount of time? I think there needs to be at the very least a review process by a clinical doctor to evaluate the mental and even physical condition of the soldiers who have seen heavy combat. This tragic event that cost the lives of innocent civilians seems like it could have been avoided  had there been a limit or review process. I'm not trying to take the soldier off the hook for what happened but there may have been a few warning signs that went unnoticed. The mental fatigue that is caused by high amount of stress that our soldiers face day in and day out and yet most of them are able to endure it and continue to serve their country is amazing. However they will take that stress home with them from the battlefield and I believe that is due to prolonged periods of deployment and recurring military tours. I'd like to get your feedback on this issue, its a serious one that I think we take for granted.