After returning from the iraq war, caddell was plagued by nightmares of the attacks. in addition, he avoided anything associated with the war and was hypervigilant for danger. he has been home for nearly six months, but these symptoms continue. caddell might have

I believe the answer is: post-traumatic stress disorder

post-traumatic stress disorder is most commonly caused by over-exposure to fight or flight situation that put themselves on a constant state of anxiety.
This disorder is usually triggered by a certain traumatic event such as the death of close ones, or a gruesome horror that is not commonly seen by normal people.