The International Herald Tribune, has an article on how post-traumatic-stress-disorder (PTSD) sometimes manifest years and decades after a traumatic event. For example, some World War II and Korean War veterans did not show symptoms of PTSD for 30-years.
As the Center for Disease Control (CDC) states PTSD can be very difficult to diagnose, which may be part of the reason why symptoms are sometimes undetected and able to brew over time.
What is at stake is that the VA is not prepared to handle delayed symptomatic cases of PTSD. The VA is currently overwhelmed with the PTSD cases of PTSD of veterans that served in Iraq, Afghanistan, Gulf War, and Vietnam. If additional doctors are not hired to assist the expected increase of the delayed symptomatic cases of PTSD a lot of veterans will suffer broken homes, lost jobs, substance abuse, and homelessness.