I like the idea of the experiment! Is it generally accepted that one would see same-day behavior changes when switching between an ADHD drug and a placebo?
That's a good point, I'm not sure. The friends I've seen use the drug as a study aid certainly respond to it quickly but the scientific rigor of the experiment didn't much matter: I think my parents were skeptical that I really had a problem anyway, and lo and behold, I'm an adult now and I never did actually have a problem. When you tell the parents of every boy in the class their kid has ADHD, the claim becomes pretty weak.