Caulfield Went to mental hospital ????

I love this book, I am about to finish reading it the second time, now I like it Even More.
Purpose today I went online to see the different interpretations others give to this book, and I Was That surprised no one saw His Brother's death as a possible cause of all his "problems" .However, It Was not about that, That I wanted to write, it is about the end of the story. Why, in this release of the book, there is not a single ward mentioning That he Went to mental hospital? I mean, I just read the last chapiter online, and complitly It was different, there he talks about His Time in mental institution, in my book, not a ward about that.