"We found that when the best behavioral management treatment and medication treatments are pitted head to head, medical treatment is a hands-down winner," said the study's lead author, Dr. Peter Jensen of the National Institute of Mental Health.
The study also concludes that a combination of medicine and behavioral therapy can be even better.
The study's main findings apply to a child's ADHD symptoms, including concentration problems and impulsiveness. But when it comes to non-ADHD symptoms such as anxiety, poor social skills and academic performance Jensen said combining medicine and psychosocial treatments was most effective.
ADHD is the most commonly diagnosed disorder in children, affecting an estimated 3 percent to 5 percent of school-age children.
The study, published in the December issue of the American Medical Association's Archives of General Psychiatry , tracked about 600 7 to 10-year-olds over a 14-month period at six locations across the United States. The study, which was done in concert with Columbia University, tried to find the most effective treatments.
A second, related study found that for children with anxiety disorders as well as ADHD, behavioral treatments alone can be just as effective as medicine.
That study, which asked which treatments worked best for specific groups of children, was written by Stephen P. Hinshaw, a psychologist at the University of California, Berkeley.
He concluded that Jensen's findings applied to all children studied regardless of gender, medication history or history of disruptive disorders. The only significant exception was children with anxiety disorders.
A child psychiatry professor at Indiana University in Indianapolis who was not involved in the study called the research some of the most significant work done in the field.
"It has tremendous implications, and hopefully it'll have a serious impact in the field," Dr. Theodore A. Petti said Monday.
The children in the study were placed in one of four treatment groups: medication alone, behavioral treatment alone, a combination of both or whatever care was available the community.
The researchers found that community care was the least effective, even though almost 70 percent of children in that group were treated with medication.
Jensen said the combined treatment "normalized" about two-thirds of the children. That means those ADHD children were indistinguishable from non-ADHD children.
Medicine alone normalized about half of the subjects, therapy worked in about one-third of the cases and community care reduced symptoms in only about one-fourth of the children.
In the study-run medication group, children were seen once a month, compare with once every four months in the community group. The number of doses received daily was higher in the study-run group, and the doctors also checked in with each child's teacher once a month.
Hinshaw also reported less consistent treatment on the therapy end.
"It was spotty at best in the community," he said. "Clinicians need to learn to work with schools and parents on consistent behavior management."