Well if you read any Josoph Heller you would know that you just asked me a paradoctal question. You see if I were rational enough to acknowledge my own mental ill being then obviosly I could not be in the state of mental ill being. So there for some one that, as you put it, was insane they could not very well tell you that.
But then if you read any Orson Wells, you could state that insanity is a matter of public perseption.
And then of course, I like cheese.