How did the past lead to Holden Caulfield's current problems? (catcher in the rye)?

I completely agree with etherealjanne but i think you must also look into his lack of attachment with his parents along with the death of his brother. and you could extend that into his awkward nature with girls is tied to his relationship with, oh i forget her name sorry, and how that rejection led to his social discomfort on the date he goes on in the book, but it isn't really a main idea i'm just throwing it out there.