Schizophrenia is the price we pay for minds poised near the edge of a cliff

"The persistence of schizophrenia is an evolutionary enigma. It is a disabling psychiatric condition that reduces the likelihood of having children, and yet it has roughly 1% lifetime prevalence worldwide. Traditional evolutionary hypotheses, such as those invoking kin selection, mutation-selection balance, and evolutionary mismatch don’t quite explain this."

Much the same could be said for gayness. If it were genetic, it should have been eliminated by evolution by now. Which suggests that it's not.

There are some differences in incidence of schizophrenia in populations.[1] Birth order matters, slightly, with prevalence higher for firstborns. (This is the reverse of homosexuality and left-handedness.) Migrants have higher rates of schizophrenia than non-migrants. Women vs. men, about the same. Rural vs. urban, about the same.

What the original paper suggests is that they didn't discover anything significant. It's more like a discussion of feedback control problems near a cliff, but by people who don't know about that part of control theory.

The title is overly dramatic for the results.

[1] https://journals.plos.org/plosmedicine/article?id=10.1371/jo...