I'm not sure one way or the other about the schizophrenia link, but it is interesting.

As far as IQ goes I completely agree. If anything I'd say that most of the people I've known who are into conspiracy theories have above average IQs.

It's one of many reasons I'm not a believer in the IQ cult. There are so many other factors that lead to success in any area. Some are biological and some are intellectual and cultural. Someone with a high IQ but insane beliefs is at a large disadvantage vs. someone with a more average IQ and more rational beliefs. If anything a high IQ person with irrational beliefs will more effectively delude themselves and others.