Good to know, I've been out of the field for well over a decade so it seems things I take for basic knowledge might have changed.

Though given Psychology's numerous issues in both sample biases, failure to replicate, and general lack of accounting for factors, I don't full trust any that "buck the norm" so to speak. I personally do not like the Big Five test as I saw first hand how easy it was to both game and end up with results that barely reflected the reality of the person during my time working with it.

While anecdotes are just that, I think we can say with some certainty that there is some correlation between higher IQs and some form of mental disordering, even if its not specific to the neuroticism type. I think an important note here is neutroticism the Big Five specific trait and "being neurotic" colloquially don't fully overlap, so someone might be clearly off but not fit the label itself in its specificity. Either way, we have far too much body of evidence of something being unstable in the higher IQs to simply write it off as "study says no."

Still its always good to think about. Personally I think people use IQ itself too fluidly as shorthand for a whole host of things, and it leads to over simplifications like these. Useful for generalized stereotypes, but maybe falls apart beyond it.