Grim (I mean serious content warning-level grim) in places, but well worth your time is Emma Seaber's thesis on anorexic life-writing as occult practice - tl;dr how do you externalise and manage chaotic and "ugly" (socially unavowable) emotional and physical extremity? How can writing itself function as an occult machine (very Burroughsian, actually)? What if a journal or diary starts to become something more like a grimoire?
Although one of the points Seaber makes quite strongly is that the stereotype of "the anorexic" as always adolescent, always a girl, is completely misleading, I still think this way of relating to writing as a magical technology is very "adolescent": what do you turn to when you want to stabilise a life-process that is no longer governable by the control routines that have managed it up until now? Adolescents glom onto books, records, systems of signifiers, all of which are accorded magical powers of attraction - they have a special affinity for me, and through them I can start negotiating affinities with others. But some people start creating their own canonical mini-universes, which may not be meant for sharing (or may carry a plea for a very special and hard-to-find sort of sharer, that one person who really "gets" you etc).