The New York Times has, lately, been exploring attention and focus issues from a variety of angles. This got my attention, because I've long been convinced that our society has it wrong when it attempts to "cure" "deficit" children. (Sorry about those quotes, but I needed both pairs to get across my dubiousness about both judgments.)
I've never read deeply on the matter. This reluctance came out of fear, because as one of my own children appeared to more and more consistently fit into the diagnosis of attention deficit, I also realized that all the symptoms applied to me as well - certainly in my scattershot childhood, if less so now. (Few would argue that I am unsuccessful at focusing now. More on that some other time.) I did not want to dig deeply into the matter because I was, to be blunt, afraid "they" would finally convince me to try to change both my child and myself.
(They did, actually. I tried to foist medication on my child several times. Luckily, he had the fortitude to resist. I feel such grief when I consider all the times I tried to make him think he was *wrong* - that there was something fundamentally wrong with him. If I could un-drag him to those professionals, if I could take back the judgement words - well, past is past, as a character in my current novel often says.)
If you're curious about the subject, or if you have a gloriously distracted person in your life, you might find some gentle commentary here. No numbers, no statistics, just some musing and gorgeous illustrations. (The one with the child looking out the window will be familiar to most of us - who *hasn't* allowed her mind to wander elsewhere during a boring lecture? But the butterfly wing one resonated with me as a terrifying consequence of our focus-mad world: we attack what is most gorgeous and creative about our own children.)
If you want a more scientific article, try this one - an early supporter of Ritalin and its ilk recants, convincingly.