Check out STRATFOR's recent article about situational awareness. It has relevance for all citizens, especially as terrorism migrates to more of a grassroots threat.
Separately, this article makes one wonder if, while on combat deployments, the sustained "focused awareness" or "high alert" and the subsequent physiological response - adrenaline - is what makes adjustment back home so difficult and contributes a to PTSD. One gets used to functioning at such a high stress and awareness level that the body simply can't adjust immediately when back home where a high level of awareness is not required. The answer seems obvious, but I think most of the studies on PTSD tend to focus on the actual events one experiences while being deployed that causes PTSD versus just the mental state required by humans in a stressful or combat environment to survive. Please feel free to share your thoughts or comments - this is definitely something I have thought about and struggled with since redeployment.