I think Holden Caulfield is/was being treated for tuberculous meningitis
When Holden is addressing us in the “present tense” context of The Catcher in the Rye , it’s clear to the readers that his current environment is purposefully vague. However, the brief amount of description of his surroundings suggests to a fairly likely theory that he is being held in some sort of mental health facility. At the beginning of the book, Holden says that he’s going to “just tell you about this madman stuff… just before I got pretty run-down and had to come out here and take it easy” (3). It’s very clear to us by the end of the book that Holden is not only having a mental health crisis, but also a physical one. This would align well with the fact that the time period of The Catcher likely doesn’t have very good resources for mental health conditions, and provide a societal motivation for why the people around him would choose to have him go to some sort of psychiatric ward— if not for his rampant depression, than for the potential tuberculosis he might have ca...