First thing: insanity. Well, to be fair I don't believe I'm insane primarily because I'm a multiple, even a fractured one. I believe I'm insane because of the OCD, the panic attacks, the walls breathing at night and the radio talking to me.

You consider yourself mentally ill, or you consider yourself insane? As ksol1460 pointed out, sanity is really a legal term concerning the ability to judge one's actions as being right or wrong.

*shrugs* Well, I always figured a lot of the "this character walked into my head" was just a description of the person's subjective experience-- that they weren't necessarily out to prove this person existed as a real separate individual.