My non-medical opinion. I think for many it is diet, exersize, and boredom related. Modern life has so many running in pointless hamster wheels and then we wonder why we can't focus on the many pointless, artificial tasks. Stop eating sugar and processed food carbs. Get to 10% or less body fat. Lift weights 2 or 3X a week and go to failure. Do stuff that you find mentally stimulating. This formula solves most problems, IMO. There is nothing wrong with needing more stimulation than most - just try to be productive about it.