No scientific proof, ( this is psychological after all) but I can see how bad parenting, high stress home environments could create ADD symptoms in children. High levels of fear and anxiety would certainly cause children to have trust issues ( authority issues) trouble concentrating(fear) and no structure to promote good study habits.
I didn't hear all of the show, but there was a researcher who was theorizing about how gratification has been for millenia our prime motivation, hunt and gather to eat, and that the concept of prolonged gratification ( ie. farming, investing, studying) are late developments and brings with it a different kind of stress that not all people are able to operate successfully. This researcher studies addiction, and was saying that things that push our instant gratification buttons are actually a survival mechanism, motivating us to hunt and gather, thus feel good. Their idea was that the motivation to hunt and gather things to survive and feel good is one of the mechanisms behind intractable addictions.