What’s Wrong with Holden Caulfield in _The Catcher in the Rye_?
Holden Caulfield suffers from post traumatic stress disorder. The fictional cause is the death of his beloved little brother, Allie.
The reason that The Catcher in the Rye is so powerful is that it is a true book (I don’t say that it is a true story). Holden is J.D. Salinger, himself, and Holden’s PTSD is Salinger’s PTSD.