I have ADHD. I've had it since I was a young child. It has been diagnosed independently at various points in my life by several psychiatrists and psychologists, most of whom are ADHD specialists. I have no doubt that ADHD continues to be overdiagnosed, especially by family physicians who don't have enough knowledge and experience on the subject. However, there are also a lot of people on Slashdot who know even less about it but still go on and on about how ADHD doesn't exist and parents just need to be more tolerant. It's not all about the parents.
Right now, I'm in the home stretch of a PhD in computer science. Getting to this point would have been nearly impossible if it weren't for getting treatment for the ADHD. At first, I tried to do without the medicine. I don't like it and I worry about the long-term effects. However, I wasn't getting things done and I was sinking into a hole to a point where I knew I couldn't possibly finish the PhD if I didn't get treatment. As it stands, medication is one component of the overall plan for coping with my inability to concentrate on my work and get things done normally. I've learned a lot of strategies from reading bits here and there, and just studying the problem as I worked my way through undergrad and now grad school. There are dozens of tactics that I use regularly that have worked well. As one example, I carry a supply of earplugs everywhere I go and use them whenever I need to study or work. There's no silver bullet, but together, they have helped a lot.
That said, without the medicine, I don't think I could accomplish what I'm trying to do. That's not a lack of confidence. It's just a realization that if you have to read 5+ research papers a week on top of a bunch of other stuff, it's not going to work if it takes you an hour to read two pages - 4-5 hours for a 10-page conference paper of any substance. Before I got on the medicine, people around me thought I might end up dropping out.
While I totally agree that overdiagnosis of ADHD is a problem, it would be kinder if folks here would recognize that for some people, ADHD it really is an important component of the problem and getting treatment can help them get on their way.
There are a variety of perspectives out there, but one that is gathering steam (and makes a lot of sense to me personally) is Thomas Brown's work on executive functioning. A couple of references: