I think that's the whole house, not just bedrooms.

That would imply ADHD was profoundly more widespread in the generations of our grandparents and before, since 10 or more people sharing an apartment or living space was incredibly common.

entirely possible that it was, but it was less of an issue when you have to haul water 3km a day and then work in the fields.

kinda like autism numbers are going up, but that might simply be because of increased diagnosis. or how "gay" isn't a new thing that's just trending -- the romans and greeks (and ottomans, and the tang dynasty, etc.) were also pretty damn gay too.

all super common stuff, just not logged as much

Idk, my grandma and my family from her generation had no problem taking a plane ride without entertainment, and didn't compensate with conversation or the seat back screen.

That makes even less sense.

It's a recent development among poor lower class stressed people, not among calm, comfortable successful people