Before I went to med school, I was similarly skeptical about the med/pharma industry. But like the global warming debate, once you understand the science, you begin to realize how facile the conspiracy theories are.

Here's the science behind ADHD: Functional MRI allows us to image actual brain activity. And there are clear differences between the brains of those diagnosed with ADHD and those diagnosed without (and yes, they do these studies blind, so researchers can't be biased).

And more recently they have found that stimulants such as methylphenidate (aka Ritalin) and others actually reverse these changes. Here is a recent study, plus a metareview (which compared several such studies):

http://www.ncbi.nlm.nih.gov/pubmed/23247506 http://www.ncbi.nlm.nih.gov/pubmed/23660970

Of course, we could still have an interesting philosophical discussion about what we label a medical condition and what are variations of normal that nevertheless have a biological basis. Clearly, ADHD is not on par with debilitating psychiatric conditions such as schizophrenia or a bipolar manic episode.

But ADHD can cause functional impairment in school, jobs, and personal relationships; it can lead to decreased happiness and satisfaction in life (and not only for the person affected, but also their families, partners, and colleagues); there are clear neurophysiological differences underlying it; and we have treatments that can make an important difference. So why not use them?

And as for the big drug companies? Most of the ADHD drugs are generic these days, so they don't profit.