Dr. Russell Barkley

They're either inherited or they come about through what we call new or de novo mutations.

I'll come back and explain that in a moment because that's fascinating.

But the second is that about 25 to 35% of the cases, particularly in boys more than girls, are acquired.

and most of the acquired injuries are occurring during pregnancy so if we break down that 25 to 35 percent at least two-thirds to three-quarters of them have had this problem due to something happening during pregnancy to the developing brain and the executive networks of the brain that leave the individual with this disorder now what could that be multiple infections that the mother has premature delivery that leads to being in a neonatal intensive care unit

leads to brain hemorrhaging in these brain areas.

We also have maternal obesity and type 2 diabetes that the mother may have.

That's kind of questionable, but that's there.

Maternal consumption of alcohol, very well proven.

If you're consuming alcohol at a high rate, you're poisoning your child's frontal lobe.

And we could go on it.

We thought smoking might be in there, but it turned out that smoking was just an index that the mother had adult ADHD.

And when you controlled for the mother's ADHD, smoking went away.

So that was kind of a marker, not a cause.

So you've got all of these, just about anything

that can happen during a pregnancy that might impact that brain, and particularly the frontal area, which is one of the most sensitive areas to injury in humans because it's so new in evolution, can cause that.

So you've got all these acquired cases, about 10% of whom acquire it after birth, through what?

Head trauma.

lead poisoning, other exposure to toxins, heavy exposure to pesticides probably.

But the biggest ones are the toxins such as lead, but especially close-head trauma.

And that can lead to this as well.