Their entire high IQ sample comes from Mensa. So this should be restated something like "Inclination to join Mensa correlates with mental and physical disorder"
Based on the posts though, the members didn't seem any smarter than the average person on HN and the discussions were generally less interesting.
The blind typically have incredible touch for reading Braille. Some also have incredible hearing. These are not physiological benefits that they get at birth; their coping mechanisms train them.
The most mentally unhealthy people are the ones that are on the lower end, but still within what we expect to function in society.
Source sadly not being verifiable since it is my psychologist wife that works with mental health in school with intelligence testing and extra resources to help those who need it.
> While the ideal would be to individually test all participants for IQ we found no scientific data that would give reason to discredit Mensa members in any country from being representative of those with high cognitive ability.
https://ac.els-cdn.com/S0160289616303324/1-s2.0-S01602896163...
I think this entire paper is bogus, it reeks of lazyness. They did not have a control group either, they used general statistics:
> Although the national surveys would likely capture a broad range of intelligence, statistically only 2% of the national data would include those with a gifted cognitive ability such those who qualify for membership in American Mensa, Ltd.
Which is false, 2% of the population does not join mensa.