Brain Imaging Targets ADHD Differences
Findings Could Lead to Better Treatments
Nov. 20, 2003 -- A brain imaging study has pinpointed exactly where the brains of children with attention deficit hyperactivity disorder differ from those of other children. Researchers say the finding could one day lead to better drugs and behavioral interventions to treat kids with ADHD.
Earlier studies have shown that children with ADHD tend to have brains that are slightly smaller than normal, and researchers have long suspected that the disorder is caused by a dysfunction in the frontal lobes of the brain, which control emotions and impulses.
The new study, published in the Nov. 22 issue of the journal The Lancet, is the most detailed look at the brains of kids with attention deficit hyperactivity disorder ever undertaken.
Differences in Both Sides of Brain
Investigators at UCLA used magnetic resonance imaging (MRI) to compare the brains of 27 children with ADHD to those of 46 children without the disorder. They found that the region of the brain associated with attention and impulse control, located on the bottom of the frontal lobes of the brain, was smaller in the ADHD kids than in the other children.
"We would expect that the abnormalities would be in this region, and this is what we found," lead investigator Elizabeth Sowell, PhD, tells WebMD.
The researchers also found that children with ADHD had larger areas of the outer layers of the brain.
Previous research has indicated that the differences were limited to the right side of the brain, but Sowell and colleagues found that they occurred on both sides.
Sowell says pinpointing the exact location associated with ADHD could help in the development of new drugs for the treatment of the disorder. Child psychiatrist and senior investigator Bradley S. Peterson, MD, says brain imaging may also allow clinicians to better utilize the therapies that are already in use.
"One of the next steps is to see if these brain differences are predictive of treatment responses," he tells WebMD. "I think it is reasonable to assume that this will be the case. Imaging may help us predict who is going to respond to certain kinds of treatment."
ADHD symptoms disappear with age in some children, but not others. Peterson says brain imaging may also prove useful for distinguishing between the two. He says studies to test all of these theories are planned.