Most children treated for attention deficit hyperactivity disorder in a major study showed sustained improvement three years afterward, according to an article in the August issue of the Journal of the American Academy of Child and Adolescent Psychiatry.

The current study re-evaluated children who had participated in the 14-month-long U.S. Multimodal Treatment Study of Children with Attention Deficit Hyperactivity Disorder (MTA).

Initial advantages of medication management alone or in combination with behavioral treatment over purely behavioral or routine community care waned; however, Peter Jensen, MD, Columbia University, and colleagues emphasized that “it would be incorrect to conclude from these results that treatment makes no difference or is not worth pursuing.”

Jensen said “We were struck by the remarkable improvement in symptoms and functioning across all treatment groups.”

After three years, 45-71 percent of the youth in the original treatment groups were taking medication. However, continuing medication treatment was no longer associated with better outcomes by the third year.

“Our results suggest that medication can make a long-term difference for some children if it’s continued with optimal intensity, and not started or added too late in a child’s clinical course,” added Jensen.

For the follow-up study, a multi-site research team evaluated, at ages 10-13 years, 485 children from the original MTA study, the first major randomized trial comparing different treatments for ADHD, published in l999. That study found that intensive medication management alone or in combination with behavioral therapy produced better outcomes than just behavioral therapy or usual community care.

Ratings from families and teachers favored combination treatment, which allowed for somewhat lower medication doses. Also, careful management of medication by MTA physicians produced better outcomes than medication provided through usual community care sources.

After 14 months of assigned treatments ended, families were free to choose from treatments available in their communities.

To understand why the initial advantage of medication wore off, the researchers examined medication use patterns that emerged after formal treatment in the study ended. They found that children who had been assigned to intensive behavioral treatment were more likely to begin taking medication, while those who had been taking medication were more likely to stop. For example, among children originally in the behavioral treatment group, the incidence of high medication use increased from 14 to 45 percent.

In a secondary analysis of the data that searched for possible explanations for the findings, in the same issue, researchers led by James Swanson, PhD, University of California at Irvine, reported finding substantial individual variability in responses to medication.

They identified three groups of children with different patterns of response. One group, about a third of the children, showed a gradual, moderate improvement; a second group, about half of the children, showed larger initial improvement, which was sustained through the third year; a third group, about 14 percent of the children, responded well initially, but then deteriorated as symptoms returned during the second and third years.

Swanson and colleagues suggested “trial withdrawals” for some children to determine if they still need to take medications.

Another report by Swanson and colleagues in the same issue confirmed an earlier finding from the MTA study that taking medication slowed growth. A group of 65 children with ADHD who had never taken medication grew somewhat larger - about three-fourths of an inch and 6 pounds more, on average ? than a group of 88 peers who stayed on medication over the three years. Growth rates normalized for the children on medication by the third year, but they had not made up for the earlier slowing in growth.

In a fourth article, Brooke Molina, PhD, University of Pittsburgh, and colleagues reported that, despite treatment, the children with ADHD showed significantly higher-than-normal rates of delinquency (27.1 percent vs. 7.4 percent) and substance use (17.4 percent vs. 7.8 percent) after three years. Earlier evidence of lower substance use rates among children who had received intensive behavioral therapy had lessened by the third year. “These findings underscore the point that ADHD treatment for one year does not prevent serious problems from emerging later,” noted Molina.

The follow-up of the MTA sample will continue as the participating children go through adolescence and enter adulthood.