From Vietnam Veterans Against the War, http://www.vvaw.org/mc/ptsd.php
The Diagnostic and Statistical Manual, III & IV says that someone may have PTSD if:
The person has been exposed to a traumatic event that is “outside the usual range of human experience and that would be markedly disturbing to almost anyone”;
The duration of the disturbance (symptoms in criteria below) is more than 1 month;
It causes significant distress in social, occupational or other important areas of functioning.
Persistent avoidance of stimuli associated with the trauma and numbing of general responsiveness (not present before the trauma) as indicated by three or more of the following:
Persistent symptoms of increased arousal (not present before the trauma) as indicated by 2 or more of the following:
Combat related PTSD is unique to each person's experience and personality but the problems seem to come in a mixture from two sources; memories of life threatening experiences and memories of what the veteran witnessed and did in the struggle to survive. Helping veterans deal with and control the anxiety and depression (fear and guilt) is best left to professional therapists. In addition to treatment, medical records and opinions from mental health professionals are critical to getting a discharge upgraded or obtaining VA benefits.
If going for treatment isn't possible, anything is better than nothing, even sitting around a local Legion hall and talking about your experiences. If you want to do more, start your own “rap” group. There are even PTSD workbooks for individuals to work alone. You can ask the local rape trauma hotline for a list of trauma therapists. And, of course, suicidal and homicidal plans or behavior require an immediate call to 911 and emergency treatment.