One aspect of Attention Deficit Disorder is a fixation with video games and television, being able to concentrate on media for hours but real life for mere seconds.
Young people exposed to lots of television (as I was as a child) learn to appreciate the editing process on a subconscious level. At an early age we learned the abbreviated vocabulary of film editing. A policeman reaches for a door handle and instantly he's in the squad car. No time is wasted with walking out to the car, filling up the tank, getting stuck in traffic or filling out the proper paperwork. Movies and TV just get to the point.
ADD is an existential frustration with how badly real life is edited.
A good screenwriter or film editor knows that if you see a rifle above the fireplace in the first act, it must go off in the third; but those of us raised with such assumptions are filled with angst that real life is nothing but a collection of unfired rifles! So our brains train themselves to weed out every piece of unneeded information. Every rifle that we feel will not go off we erase from our attention immediately. We constantly scan our surroundings and judge them, and take in only the things that are guaranteed to be of value (or entertainment value) once things get interesting.
ADD is not a disease, it is a vestigial survival instinct.
The human race never would have lasted if cavemen took mental note of the scent of every blossom of honeysuckle in valleys filled with Sabertooth tigers. So we rapidly shift our focus and trim the bits that don't pop out at us. This is not a disorder, it is an amazing skill that took millions of years to hone.
As our role in the world continues to change, which other evolutionary advantages will we feel the need to medicate into submission?