Here's a lecture by Robert Sapolsky where he goes into some theories involving schizotypal individuals (and other mental disorders) and culture: https://www.youtube.com/watch?v=4WwAQqWUkpI
Long story short, the theory goes that being schizotypal (but not full-blown schizophrenic) could be an advantageous trait in human society, usually by filling some spiritual, ritual, or religious role in the group. These people are high status in their societies, and have many chances for passing on their genes.