There's a long running issue that the psychiatric profession have a tendency to label things quickly and simplistically, using not very precise or scientifically robust methods. These 'broad brush' labels get picked up by the media and then by the drug industry, who produce 'medications' for vague or even non-existent conditions. Often these medications have harmful side effects and turn out on close examination and in hindsight to have been the wrong thing entirely. We should never underestimate how powerful the psycho-pharma industry is, the profits to be made from new conditions and the propaganda machine announcing them.
Meanwhile, back in the real world, there doubtless are some children with some sort of real medical issue who display 'ADD' or 'ADHD' and there are also a lot of children who have simply been labelled that, lazily in some cases, in order to medicate them, often with very harmful long term consequences.
This is also of course a gift to reactionary politicians like Duncan Smith, who support a Victorian hang 'em and flog 'em and give 'em five cold showers a day educational methodology.
It's rare for proper scientific discussion or real practical knowledge to burst through all this and for a proper discussion to take place that carefully considers the evidence.