I don't think PTSD is what you think it is. PTSD is an anxiety disorder. It doesn't make people evil or crazy or radical. In World War 1 it was called Shell Shock, and many soldiers were executed for desertion because of it.

I've never heard of any symptom that Hitler had that sounded anything like PTSD. Antisocial personality disorder or something similar, perhaps, but there are serious problems with trying to diagnose people in the past with mental disorders. He spent half his time in World War 1 at regimental HQ in any case, far behind the front lines.

Take a look over http://www.nhs.uk/Conditions/Post-traumatic-stress-disorder/Pages/Symptoms.aspx and the symptoms of PTSD. You can see that most of them aren't very conducive to running a major belligerent in a world war.

Finally, things like anti-semitism and the belief that the treaty of versaille were humiliations weren't exactly radical beliefs. Many of Hitler's ideas were fairly mainstream in the groups he ran with.

I'd recommend Hitler: A Biography (Kershaw 2008) if you want to know more about how Hitler came to his beliefs and ideology.