Sorry, Lord Bear; while I can fully tolerate a man like that, I already
married one!
What Trippin calls a psychopath was known as sociopath in the DSM-IIIR and antisocial personality in the DSM-IV. For a good example, look at Faith on Buffy the Vampire Slayer or consider such serial killers as Ted Bundy.
There is so much insanity and similar problems in the world that it is difficult to say that all of it correlates with intelligence. Certainly schizophrenia (which is NOT multiple personality disorder) does seem to correlate. It is theorized that artist Paul Cezanne was schizophrenic. Usually these folk are thinking of all sorts of amazing things; the problem is they often have difficulty relating to the rest of the world on its terms.
Perhaps that's the thing we consider insane, simply not being part of the world around you. This could be as small as being a little airheaded like Einstein, or as big as not being able to talk to people because you can't hear them over the roaring in your own head. So if that's the case, then it does correlate with intelligence as the cab survey suggests: smarter people are too busy thinking of other things to be fully in the moment.