Researchers who pinpointed brain differences in people with attention-deficit/hyperactivity disorder (ADHD) say their findings show the condition should be considered a brain disorder.
The international study — the largest of its kind — included more than 1,700 people with ADHD and more than 1,500 without the disorder. Participants were between the ages of 4 and 63.
“We hope that this will help to reduce stigma that ADHD is ‘just a label’ for difficult children or caused by poor parenting. This is definitely not the case, and we hope that this work will contribute to a better understanding of the disorder,” said study author Martine Hoogman.
ADHD is characterized by inattention, overactivity and impulsivity that can interfere with learning and relationships.
Brain scans revealed that five brain regions in those with ADHD were smaller than in those without ADHD. The greatest differences were seen in children, according to Hoogman. She is a postdoctoral researcher at Radboud University Medical Center in Nijmegen, the Netherlands.
“These differences are very small — in the range of a few percent — so the unprecedented size of our study was crucial to help identify these. Similar differences in brain volume are also seen in other psychiatric disorders, especially major depressive disorder,” Hoogman explained.
The study, published Feb. 15 in The Lancet Psychiatry, refutes the notion that ADHD is the result of poor parenting, the researchers said.
“The results from our study confirm that people with ADHD have differences in their brain structure, and therefore suggest that ADHD is a disorder of the brain,” Hoogman said in a journal news release.
In an accompanying editorial, Dr. Jonathan Posner hailed the findings.
“This study represents an important contribution to the field by providing robust evidence to support the notion of ADHD as a brain disorder,” he wrote. Posner is an associate professor of psychiatry at Columbia University Medical Center in New York City.
The U.S. National Institute of Mental Health has more on ADHD.