Researchers are learning more about the brains of children who have attention deficit disorder.
A new study finds that crucial parts of their brains develop more slowly than the brains of other children.
According to the research, the parts of the brain that lag behind -- by as much as three years -- suppress inappropriate thoughts and actions, focus attention, and remember things from moment to moment.
The researchers, led by Doctor Philip Shaw of the National Institute of Mental Health, report their findings in the Proceedings of the National Academy of Sciences.
He says finding that the brain eventually matures in many of these children "should be reassuring to families."
But not all children outgrow it. And a co-author says researchers are trying to find out the difference between those who do and those who don't.