Creativity evolved as a coordinated package of ability (especially high general intelligence), a creative mode of thinking (inner directed), spontaneous interest, and the motivation to pursue this -creative-ability-interest.
Therefore, high Psychoticism Creativity is an adaptive phenomenon - 'designed' (by natural selection) for the purpose of a proportion of individuals in the population being creative (e.g. innovating in ways beneficial to the group, solving difficult problems afflicting the group etc.).
So, the creative way of thinking, i.e. the 'flight of ideas', wide associations, awareness of the stream of consciousness, tendency to have visions and to get non-logically-derived ideas are not examples of mild pathology, not in their essence mini-Psychotic-illnesses - but they should instead be considered hard-wired systems for creativity.
This is emphasized by the way in which the creative way of thinking does not stand alone, but is linked to ability, interests and motivations - all of these being strikingly inner-originating, and inner-fuelled.
Thus, creativity is a coordinated package: an adaptive package.
(And, conversely, creativity is NOT - except perhaps very unusually - a rare and accidental combination of pathologies which 'just happen' to yield beneficial results.)