Researchers say that children with attention deficit hyperactivity disorder (ADHD) have a disruption or disturbance in brain circuitry, a problem that may now be seen using brain imaging techniques.

Those same images are providing evidence that using drugs like Ritalin to treat ADHD can repair these brain short circuits.

Manzar Ashtari, PhD, associate professor of radiology and psychiatry at North Shore-Long Island Jewish Health System in New Hyde Park, N.Y., says children who have undergone long-term treatment with stimulant drugs “have fewer of these disruptions in circuitry.”

"Typically ADHD is described as a chemical imbalance, but our research has shown that there may also be subtle anatomical differences in the brain that are more important in this disorder," says co-researcher Sanjiv Kumra, MD, a psychiatrist at Zucker Hillside Hospital in Glen Oaks, N.Y.

Ashtari says the disruptions are found in pathways involved in the ability to concentrate as well as regulate impulse control, motor activity, and inhibition, “all areas that are key symptoms in children with ADHD.”

Her studies used a magnetic resonance imaging (MRI) technique called diffusion tensor imaging.

She tells WebMD that diffusion tensor imaging allows scientists to not only visualize structures of the brain "but to peel away layers of the brain and let us dig down into the brain and visualize the wires that connect circuits."

In her preliminary study she compared brain activity in 18 children with ADHD to brain activity in 15 non-ADHD children by merging the images. Using this overlay technique, she was able to identify specific brain regions where disruptions were common.

In a second study, Ashtari and colleagues enrolled 10 children with ADHD who had never received medication to treat the condition and 10 ADHD children who had been treated with Ritalin or other stimulant medication for an average of two-and-a-half years.

She says she only compared children treated with stimulant medications, not non-stimulant medications that are also sometimes used to treat ADHD. Other stimulant medications used to treat ADHD include Adderall and Concerta.

The study showed that children with ADHD who had received stimulant medication to treat their condition had fewer anatomical brain abnormalities.

Though Ashtari’s studies are intriguing, Michael Brant-Zawadski, MD, medical director of radiology at Hoag Memorial Hospital in New Port Beach, Calif., cautioned against too much enthusiasm for the results. “I don’t think this work is ready yet for prime time. It will require further studies to see if these results can be reproduced,” he says. Brant-Zawadski was not involved in the studies.

By Peggy Peck, reviewed by Brunilda Nazario, MD

SOURCES: The Radiological Society of North America 90th Scientific Assembly and Annual Meeting, Chicago, Nov. 28- Dec. 3, 2004. Manzar Ashtari, PhD, associate professor of radiology and psychiatry, North Shore-Long Island Jewish Health System, New Hyde Park, N.Y. Sanjiv Kumra, MD, Zucker Hillside Hospital, Glen Oaks, N.Y. Michael Brant-Zawadski, MD, medical director of radiology, Hoag Memorial Hospital, New Port Beach, Calif.