I have a Neanderthal toe (also called a Celtic toe) on my left foot. That toe is much shorter than the toe next to it. I also would have been diagnosed with Attention Deficit Disorder when I was a kid, although the diagnosis didn't exist at that time.
I know a woman who has two Neanderthal toes - and she is schizophrenic.
The late Stan Gooch claimed that such "disorders" such as bipolar disorder, ADD and schizophrenia are not true disorders. They're adaptations to the environment and come from our Neanderthal ancestry. (He also predicted, correctly, that Neanderthals had red hair).
Gooch called it the Hybrid-Origin Theory and believed that Cro-Magnons and Neanderthals interbred.
Recent research has found that those of European ancestry average some 4% Neanderthal DNA. So it turns out Gooch was right. Of course some people will have more Neanderthal DNA and some will have less. I have wondered for a few years about the relationship between Neanderthal toes and various "disorders."
My left foot would be controlled by the right side of my brain. So it seems to me there is something different about right side of my brain. I have never seen any research about this but I'd like to see it, especially since my schizophrenic friend has those two toes.
To me it's not surprising that on the Myers-Briggs test I come up as an INTJ - Introverted Intuitive Thinking Judging. INTJs make up about one percent of the population. We operate on intuition first and reason second - and intuition is supposed to be due mostly to the right side of the brain.
So I'm an INTJ with a Neanderthal/Celtic toe on my left foot, and who has ADD without Hyperactivity.
I have also come to the conclusion that what we eat affects our brain. I personally don't eat sugar or grains. I eat what is commonly called the Paleolithic Diet - which I'm sure is what the Neanderthals ate.
I don't much believe in Evolutionary Psychology, which is mostly an embarrassment, but I'll accept Dr. Emily Dean's definition:"I tend to think in terms of the human body and gut and neurons working outside design specs, thus breaking down (that is 'my' version of evolutionary psychiatry."
Concerning nutrition, she wrote this: "Part of my major hypothesis is that the industrial/digital age and processed, low-nutrient food has brought out more severe and different phenotypes of underlying vulnerabilities, and has also brought out seemingly new illnesses ('atypical depression')."
Since changing what you eat affects your emotional health, then psychiatric "disorders" can be cured by nutrition. And this is exactly what I have noticed. I have read of several cases of people "curing" themselves of bipolar disorder by quitting grains. Some said they ceased taking medication they had been on for 20 years.
I am unfortunately outside the design specs. I've known it since I was 12. My teachers knew it long before I but were too ignorant to realize what was going on (they blamed the problem on me).
The writer and radio personality Thom Hartmann called people with ADHD "Hunters in a Farmer's World." I think he was a point - a big one. He claims that what he calls "hyperfocus" comes from our hunter/gatherer past. (I also have that hyperfocus, as do all INTJs).
Hyperfocus is defined as "an intense form of mental concentration or visualization that focuses consciousness on a narrow subject, separate from objective reality and onto subjective mental planes, daydreams, concepts, fiction, the imagination, and other objects of the mind."
It's why Adam Smith, author of The Wealth of Nations, would go for walks and night and got so absorbed in thinking he once fell into a ditch. I've done the exact same thing.
Some kids don't do very well in school at all. I was one of them. People like me aren't made in sit in ranks and rows in school. I can't imagine Neanderthals doing that, either.
Thom Hartmann has made the comment, "...those who think ADHD is a 'top down' problem, such as a failure of cognition, inhibition, or even poor parenting, are totally and utterly wrong." In other words, people are born with it.
We need more research on all of this.