I'm just gonna go on a rant because I can. ADD and ADHD are a thing. It just seems to be something that is over diagnosed. Kids will have focus problems when they're young. They're still learning how to behave in school and shouldn't be expected to know how to behave in first and second grade. By the time a kid has been in school for a few years, it might be more common to pay attention and stay calm during a class. I'm not a professional I'm kind of just guessing at all of this.
When I was in grade school, I honestly could not pay attention for the life of me. I would take notes and study, but retaining information and getting myself to not zone out during a class was hard. In sixth grade I was told I have ADD. I was put on medication, Focalin at the time, and things got a little easier for me. A year after that I was put on Vyvanse, which I am still on today. I'm in college now, and I've really noticed the impact my ADD has during my classes and studying when I don't take my meds.
Going back to the over diagnosed thing. What I think is that some people are hearing about ADD or ADHD and bring it up because they believe that's why their child is doing poorly or is acting out in class. I think it might be best to wait until a child is a bit older to really look at the problem, or monitor their study habits and make sure they're just not jerks...because unfortunately some kids are just jerks.
That's my little rant. Don't quote me on anything, since I'm only guessing at stuff here. I'm just a nineteen year old who happens to take Vyvanse so she can get through classes and studying so she can eventually graduate.