Will Kids Outgrow ADHD?

New findings that attention-deficit hyperactivity disorder may stem from a developmental delay that children could outgrow, rather than a cognitive deficit, have raised questions for parents of the 4.4 million children diagnosed with the disorder.

The findings from a National Institute of Mental Health study, published online by the Proceedings of the National Academy of Sciences, compared brain scans of 446 children with and without the disorder. The brains of children with ADHD appeared to develop normally but more slowly, lagging on average about three years behind other children.

We spoke with several experts about what the findings might mean for parents.

Why the sudden change in thinking?

It's not really sudden. Scientists have long suspected that ADHD may be tied to delays in brain development, but until now there has been little biological evidence. In the new study, biological differences were most evident in the cortex, the part of the brain that governs attention, planning and judgment. On average, in children with ADHD, thickening of the cortex appeared to peak at age 10.5, compared with age 7.5 in children without the disorder.

"It helps present a better, non-stigmatized, biological explanation for why . . . some kids have ADHD symptoms," said William Coleman, professor of developmental and behavioral pediatrics at the University of North Carolina and chairman of the Committee of Psychosocial Aspects of Child and Family Health at the American Academy of Pediatrics. "They're not bad, not lazy, not unmotivated. They don't have bad parents. They just have a developmental lag."

Does this mean that my child will outgrow his ADHD symptoms by the time he's a teen?

Perhaps.

"[The study] doesn't show that the brains of kids with ADHD completely 'normalize' by age 12 or so," the study's lead author, Philip Shaw, wrote in an e-mail last week. "We only looked at one aspect of brain development. Many other structural and functional brain differences persist in the brains of teens with ADHD."

"While a lot of people with ADHD do improve with age, as many as two-thirds still have symptoms of the disorder which persist into adulthood," Shaw said. Among possible explanations: There may be more than one genetic variant of the disorder, or perhaps some kids with ADHD have other conditions that are responsible for their symptoms.

"The primary problem may be a learning disability," Coleman said. "[Researchers] say that once the cortex thickens, kids get better, but if they have ongoing, undiagnosed problems, their symptoms may persist."

So, should I stop giving my child stimulant medications, such as Ritalin, to help with attention problems?