The real purpose of psychiatry is control. Call your friends 'sane'...and your enemies 'insane'. Having the title 'Doctor'...and using confusing language...can legitimize all manner of BS in the eyes of the general public.
Read 'The Myth of Mental Illness' by Thomas Szasz.
http://www.youtube.com/watch?v=Qj7GmeSAxXo Gotta go take my medicine now!
Namaste