I promised before to write a blog about how ADHD seems to be better for survival so here it is.
The first thing I'd like to point out is the distinction between living a good life and surviving. They're not the same thing. All that matters for the survival of a species is that it survives long enough to reproduce. Anything above that is a bonus. So I'm not trying to say ADHD is better in general. It's just better for survival.
Tyeada wrote before about our dependence on technology. I tend to think this is a good thing as long as you can manage without the stuff you depend on for a short period of time, just in case you lose it.
Take for example people who wear eye glasses. I think if it weren't for eye glasses, people with bad eyes would have a slightly more difficult time trying to make it in life. It wouldn't be a huge difference but I think it would count enough to weed out the genes related to bad eyes over a few generations.
With ADHD, the kids depend on stimulants like Ritlin to increase the brain activity in the prefrontal cortex. This is the area in charge of impulse control. ADHD doesn't seem to affect the older, more emotional part of the brain -- the amygdala. As long as they can depend on the medication in the early years of their life and be at least somewhat successful with their education, they'll be fine to reproduce.
Then after school, couple young hormones with impulsiveness and you have a group of people more prone to getting pregnant. Hense, it is better for survival.
Below is a map of the incidence of ADHD. I think it looks the way it does because it's hereditary and it seems to be spreading from the east coast westward. The fact that it's a growing population would suggest that it's better for procreation. It could be for other reasons but I don't think it is.