It is also important to collect information about the family history/background to rule out any serious emotional disturbances.

And maybe a bit more than that. A lot of "ADHD" is the result of what might be called home antischooling - when what goes on in the home environment makes it impossible for the kid to learn anything either there or at school. Things like sexual abuse and parents keeping the kids awake all night with drunken arguments are the well-publicized ones. But even in the absence of anything that might attract police intervention, a kid is never going to learn to sit and think (either at home or school) while living in a home environment where there is never any silence, nobody ever settles down to a sustained task that takes any time, and the only escape from non-stop TV and videos is being left alone in your room to play millisecond-response computer games all evening.

One peculiarly sick situation I know of in a Scottish region near here: the local authority set up a very effective network for parents of kids with ADHD. The parents were largely in control of it but professionals were on call as needed. They used a wide range of interventions, everything from Ritalin to ensuring that kids ate meals on a regular schedule, laid off junk food and Red Bull, and didn't have TVs or computers in their bedrooms. None of this stuff is rocket science and it didn't take too long before the parents figured out how to manage the problem. It didn't take much longer before a lot of them decided not to manage it. The benefits paid out to families with an ADHD kid were high enough to make a substantial difference to the weekly budget. An ADHD kid was effectively an extra wage earner, so long as they stayed messed up enough.

Something like that is equally a problem for home-based or school-based education, but the answer is never going to come from the parents.