14 October 2002
different view of attention deficit
Researchers say the problem may be genetic and develop prenatally.
Brain scans of 152 children show anatomical variations.
Shari Roan, Times Staff Writer
brains of children with attention deficit hyperactivity disorder
are clearly different from those of normal children, a new brain-imaging
study has shown, providing further evidence that the problem is
study of 152 children casts doubt on lingering theories that ADHD
is caused by food allergies or isn't a real illness. Instead, the
research shows, children with the disorder have anatomical differences
in several parts of the brain, which probably accounts for the symptoms
of restlessness, poor concentration, distractibility and talkativeness
they typically experience.
looks like the whole brain is involved with ADHD, but some parts
are more affected than others," said Dr. Francisco X. Castellanos,
director of the Institute for Pediatric Neuroscience at the New
York University Child Study Center and lead investigator of the
brain scans taken over 10 years, the study compared the children
with ADHD with 139 normal children in the same age range. Although
Castellanos calls brain studies on ADHD "primitive," the
study produced several findings that should enhance the understanding
of a disorder that affects about 5% of children.
studies suggested that the front part of the brain is altered in
ADHD children, but this study showed differences in several regions
of the brain.
brains of ADHD children were 3% smaller in volume compared with
brain differences remained the same through a child's development,
which suggests the differences are fixed.
brain differences among ADHD children who took medication, such
as Ritalin, and those who did not were similar. That suggests that
it's not the medication that causes brain differences, as some researchers
have suggested, Castellanos said.
medication helps resolve the symptoms of ADHD in some children,
"medication didn't change the brain," Castellanos said.
study did show, however, that children with ADHD who took medication
were similar to normal kids in terms of the brain's white matter,
which contains nerve fibers. Although far from proven, that could
suggest that medication enhances the normal development of that
part of the brain, he said.
fact that the brain differences remain largely unchanged suggests
that the cause of ADHD occurs prenatally -- it could be genetic
-- or early in life, giving researchers more avenues to explore
regarding the causes of ADHD and variations of the disorder, he
research also should reassure parents, teachers and children with
the disorder that no one is to blame for difficulties children encounter.