Suggest me a book for the mentally ill.

Not just for the mentally unstable, but one thats mainly about a character thats mostly alone and empty. I want a book that perfectly displays the heaviness and pain of depression, BPD, or other illnesses. I also wish it wouldnt have any romance at all(dark or not.) I get frustrated easily with fictional characters sometimes, so any villain or abusive, drug addict love interest or a too realistic, hateable secondary character should be few to none in this book(like girl in pieces with the domestic abuse.) It may be a novel, educational book, biography, or what. I dont want it too disturbing, yet disturbing enough to display mental illnesses(if it doesnt contradict one another too much.) I just want something that could make me feel atleast abit more real and less alone with my experiences.

Please tell me if my request is too contradicting or specific. This would be my second book to read.

Edit: Thank you everyone for all the books. Now i just have to find a place where these are known and sold in a southeast asian countey.