Not my area of expertise, so it should be taken with a boulder of salt, but there are other studies that seem to indicate a much higher correlation. Part of the problem may be that “creative” is a nebulous term. One Swedish study found that people with artistic backgrounds have a 1.9x likelihood of developing schizophrenia and 1.62x odds of developing bipolar disorder.

I suspect (with nothing to support it) that there is a range where people with mental illness are able to interpret the world differently than normies (and thus make connections that normies do not), but also a point where that perception gets so out of joint that they can no longer function in reality. So in the former case, it may help in creative pursuits, but the latter may hamper it.