I think the symptoms/behavior comes first, and the screens come after. My son
cannot sit still. He’ll wiggle, jump, run and try to touch/lick everything in existence if he’s not entertained, and what he finds entertaining is exactly the things I mentioned before.
And youtube.
It’s literally the only way to get him to sit still for any amount of time (that I’ve found anyway), so that’s what restaurant time has become.
Doesn’t mean he always wants to or gets to watch a video, especially if he can run about outside instead, but if we’re eating in a restaurant that’s otherwise dreadfully boring to him, yeah.