coursework book recs please!!

hi! for my english coursework we have to write our own fiction writing piece and a creative non fiction piece. our work will based around 2 books that we can chose, but they have to link. i think i have found my fiction book – ‘It’s Kind of a Funny Story’ by Ned Vizzini – but i need a non fiction text as well, and that is where i’m stuck. i want to do my work surrounding my time in a psychiatric hospital and i was hoping to find a non fiction book that reflected this. according to my teacher, non fiction can be pretty much anything, for example an (auto) biography or a collection of letters. i’ve been trying to find some letters about mental health as the basis for my non fiction – but i’ve not had much luck (or maybe i haven’t looked very hard, i’m not sure). i should add that the book has to be classed as ‘literary’ and worthy of academic study.

i’m very open to anything, i just thought letters would be a good place to start! any help appreciated – my fiction text is not set yet either so if you have any other recs for that they are more than welcome!!