Brain development found to be slower in children with ADHD

Brain development found to be slower in children with ADHD
Children play in a playground as the sun sets in this file photo from June 5, 2004. (John Kolesidis/Reuters)CHICAGO (Reuters) - Children and teenagers with attentiondeficit hyperactivity disorder have developmental delays of upto three years in some regions of the brain, U.S. researcherssaid on Monday.
"The sequence in which different parts of the brain maturedin the kids with ADHD was exactly the same as in healthy kids.It's just that everything was delayed by a couple of years,"said Dr. Philip Shaw National Institutes of Health's NationalInstitute of Mental Health.
Shaw said the delays are most pronounced in regions of thebrain that are important for controlling thought, attention andplanning.
ADHD is a condition suffered by about 2 million U.S.children that often becomes apparent in preschool and earlyschool years. Children with ADHD have a tougher timecontrolling their behavior and paying attention.
Shaw said the study helps settle the question of whetherthe brain develops differently in children with ADHD or is justdelayed. "This is very much in favor of a delay," said Shaw,whose study appears in the Proceedings of the National Academyof Science.
The finding was based on imaging studies involving 223children and teens with ADHD and 223 without the disorder.
Researchers used magnetic resonance imaging, or MRI, scansto look at the brain structure at various ages, measuring thethickness of the developing cortex, a key area for attentionand impulse control.
While prior imaging studies have mostly relied on measuringthe four lobes of the brain, Shaw and colleagues used a newtechnique that enabled them to measure the thickness of braintissue in 40,000 different sites in the cortex.
They focused on the age at which cortex thickening peaksduring childhood, then starts to thin after puberty as unusedneural connections are pruned.
They found that in children with ADHD, the cortex reachedpeak thickness at an average age of 10.5, compared with age 7.5in normal children.
"The delay was carried forward into adolescence," Shaw saidin a telephone interview.
He said the study was not able to answer the question ofwhy some kids grow out of ADHD, nor does it address anyquestions about the benefits of treating children.
"What I wouldn't take away from this study is: 'Just sitand wait three years and your kid will be OK,"' Shaw said.
"We know ADHD is a real problem for children and theirfamilies and the schools, and it does need treatment," he said.
Treatment often includes drugs like Ritalin, ormethylphenidate, a stimulant intended to lower impulsivenessand hyperactivity and boost attention. It also may includebehavioral strategies to help children and their familiesmanage the disorder.
A study published in September found that fewer than halfof U.S. children who meet diagnostic criteria for ADHD receivetreatment.
(Reporting by Julie Steenhuysen, editing by Will Dunham andStuart Grudgings)