Holden Caulfield is the teenage protagonist of the 1951 novel Catcher in the Rye, written by J.D. Salinger. He goes through lots of sadness and issues throughout the story which suggests that he has a few if not many mental disorders such as depression, bipolar disorder, etc. He shows signs of many of the symptoms to support the idea that Holden has problems.
SYMPTOM #1: Lack of Interest.
In the depression research, it states that some of the symptoms are irritability and loss of interest or pleasure in hobbies and activities.
"What I was really hanging around for, I was trying to feel some kind of a good-by. I mean I've left schools and places I didn't even know I was leaving them. I hate that. I don't care if it's a sad good-by or a bad good-by, but when I leave a place I like to know I'm leaving it. If you don't, you feel even worse."
Holden struggles to find things to occupy himself when he is in New York. He tries to do multiple things. He tries almost about everything he can do and always finds himself being disappointed. This could be considered a symptom of depression. Holden seems to create fortifications around himself to disappoint himself in certain situations. For example, he never tries to "break out of his barrier" in order to try new things and have fun.
SYMPTOM #2: Substance Abuse
People with bipolar disorder may also misuse alcohol or drugs, have relationship problems, or perform poorly in school or at work. Family, friends and people experiencing symptoms may not recognize these problems as signs of a major mental illness such as bipolar disorder.
"I was half in love with her by the time we sat down. That's the thing about girls. Every time they do something pretty, even if they're not much to look at, or even if they're sort of stupid, you fall half in love with them, and then you never know where the hell you are. Girls. Jesus Christ. They can drive you crazy. They really can."
Holden may suffer through substance abuse because it states they have a misuse of alcohol or drugs, in which Holden is constantly trying to purchase alcohol at bars and such he goes to, have relationship problems, in which Holden has a fight with Sally and can't find anybody to hang out with, and/or perform poorly in school or at work, in which Holden did throughout his school life and would constantly get kicked out of his schools, finding himself in multiple different types of plights.
In conclusion, I believe Holden may have a few issues involving depression and bipolar disorder. He experiences a lack of interest in most things and has many problems involving his work ethic at school, relationships, and a misuse of alcohol and drugs as he's constantly trying to buy a drink and smokes a lot.