Okay, I lied. ADHD is real, but it's heavily over diagnosed. But almost everyone diagnosed with it shows off symptoms, this most likely just a placebo. Diagnoses of the disorder shows an age bias. Students in the same grade but different birth days are diagnosed differently. Children with earlier birthdays are less likely to be diagnosed than children with later birth days. So when there's a class filled with 10 and 11 year olds, the 10 year olds are more likely to be diagnosed. Not only that, but there's also a gender bias. Females are less likely to be diagnosed than males. This is just because of gender bias, and not because of the minor differences between the male and female brain. http://psycnet.apa.org/journals/ccp/80/1/128/ http://bjp.rcpsych.org/content/184/1/8.short I didn't really read this second link because if I do, I'm going to have to do a bunch more research on it. So I'll just leave it here for you guys. Now, this subject is somewhat deep and I'm not sure if three links are enough but that's what I'll leave here for now. And I encourage everyone go out and do research on the subject by themselves, either it be for or against my point.