Dr. Russell Barkley

So you can see that there's more than just dopamine.

And now we realize that it goes beyond neurochemistry because the genes we're discovering for ADHD, of which we've already found 12, we're guessing there's at least 45 to 50.

There's actually a recent paper from last week that shows that it's probably closer to 500.

But there are multiple genetic sites in the human genome that build and operate your brain.

And ADHD results from having different genes.

pairs of these genes than other people have.

So you and I both might have the dopamine gene DAT1, but your version is different than my version.

You might have seven, eight or nine copies of the DAT1 gene, whereas the average person has four or five.

And those extra versions are wreaking havoc in building the brain.

they're creating a very different brain than other people get.

And we see this very early in the development of the brain where nerve cells that are under the control of these genes are not migrating properly.

They're not growing properly.

They're not reaching the endpoints in the brain where they should be connecting properly.

And it leads to problems with connectivity in different brain centers.

There was literally a paper yesterday published on 32,000 people with ADHD

demonstrating beyond a shadow of a doubt, these functional connection difficulties in children developing ADHD.

So it was just staggering to see the number of different regions that are not connecting as well as they should.

And even when they connect, the connections are quite variable in how well they function, creating a lot of variability in behavior.

So, you know, just to say that we're linking behavior with brain, brain with genes, genes with functional connectedness in the brain.

And you just have to sit back and go, wow.