I found this info on a combat-veteran's site:

PTSD Characteristics in Veterans:

INTRUSIVE THOUGHTS AND FLASHBACKS
Replaying military experiences in their minds, searching for alternative outcomes. Flashbacks triggered by everyday experiences: helicopters, smells, green tree lines, popcorn popping, rainy days.

ISOLATION
He has few friends. Isolates family emotionally and sometimes geographically. Fantasizes about being a hermit, moving away from his problems. Believes no one can understand and no one would listen if he tried to talk about his experiences. Isolates himself from his partner, family and others with a "leave me alone" attitude. He needs no one.

EMOTIONAL NUMBING
Cold, aloof, uncaring, detached. Constant fear of losing control -- "I may never stop crying".

DEPRESSION
Sense of helplessness, worthlessness and dejection. Lacks self-esteem and suffers from great insecurity. Feels undeserving of good feelings. Seems unable to handle it when things are gong well.

ANGER
Quiet, masked rage which is frightening to the veteran and to those around them. Unable to handle or identify frustrations. Unexplainable, inappropriate anger.

SUBSTANCE ABUSE
Used primarily to numb the painful memories of past experiences. Heavy use of alcohol, nicotine, caffeine and other drugs.

GUILT/SUICIDAL THOUGHTS AND FEELINGS
Self-destructive behavior. Hopeless physical fights, single car accidents, compulsive blood donors. Self-inflicted injuries to feel pain -- many accidents with power tools. High suicide rate. As soon as things are well off, doing something to lose it all, or walking away from it. Survivor's Guilt when others have died around them.

ANXIETY OR NERVOUSNESS
Uncomfortable when people walk close behind them or sit behind them. Conditioned suspicion, he trusts no one. Startled responses.

EMOTIONAL CONSTRICTION
Unresponsive to self, therefore unresponsive to others. Unable to express or share feelings, can not talk about personal emotions. Unable to achieve intimacy with family, partner or friends.

DENIAL
Unable to admit that he has any of the above symptoms or that he may have PTSD. May deny that his military experience could have anything to do with his attitude. In extreme cases, will deny that he was even in the military. Unwilling to seek help. Trusts no one.