Having read Heavier than Heaven, I felt I could relate to alot of his internal struggles and inability to figure out who to trust, the need to be recognised for talent, and yet the need for isolation. (Bear in mind the hidden track on Nevermind "Endless, Nameless" is Kurt having a meltdown and smashing his guitar because he couldnt get his guitar parts right) there is also a Youtube video where he gets annoyed and requests on the microphone that the floodlights be turned off because theyre too bright for him. However, there was also a deep, psychotic deppressiveness to him, perhaps if he was, it was comorbid with bipolar?