holy king
Deity
As far as charges of mental illness, I don't think there is any evidence for it unless we assume that everyone who claims to talk to God is mentally ill.
well, if he talks back it most probably is a form of "illness". (one that may very well still give you the possibilty to not be dangerous to society/yourself or even function within it like the norm. so it's more of a mental "problem" then...)
that may either have neurological or psychological reasons.