ADHD Drug Does Stunt Growth

After 3 Years on Ritalin, Kids Are Shorter, Lighter Than Peers

By Kathleen Doheny
WebMD Health News

Reviewed By Louise Chang, MD

July 20, 2007 -- Three years after starting treatment for attention deficit hyperactivity disorder (ADHD), children continue to experience improvement in their symptoms regardless of which treatment they use, a major follow-up study shows. But the advantage of medication, shown to be superior to other treatments in previous follow-ups, seems to wear off. And some improvement in symptoms may occur naturally, independently of treatment.

At the three-year follow-up mark, "the kids by and large had improved a great deal," says Peter S. Jensen, MD, author of one of four reports issued on the study. Called the Multimodal Treatment Study of Children with Attention Deficit Hyperactivity Disorder (MTA), the study first enrolled children with ADHD when they were ages 7 to 10. These reports, the third follow-up on the study, are published in the August issue of the Journal of the American Academy of Child and Adolescent Psychiatry (JAACAP).

But the news isn't all great. In a surprise finding, the effect of ADHD medications, initially shown to be superior to other treatments such as behavior therapy, was found to provide no better results at the three-year mark than the other approaches. And the risk of behavioral problems in ADHD children, including their tendency to experiment with drugs and alcohol and to display delinquent behavior, was found higher than in other children, which the researchers expected.

About 2 million U.S. children are diagnosed with ADHD, a condition in which children have trouble focusing on tasks, sitting still, and paying attention.

Medication and Behavior Therapy for ADHD

The latest follow-up study on which treatments worked best evaluated 485 of the original 579 children when they were ages 10 to 13. The original study, which continued for 14 months, evaluated four approaches: behavior therapy, medication, medication plus behavior therapy, or routine community care. After the 14 months, families could choose from treatments available in their communities, and the original groups may have added or eliminated the treatments they first took in the study.

By the three-year mark, the percentage of children taking ADHD medication more than half the time had changed across the initial treatment groups, with 45% of the initial behavior therapy group, for instance, taking medication. Overall, 45% to 71% of children were taking ADHD medication at the three-year follow-up. But the medication was no longer associated with better outcomes -- such as symptom control -- than the other approaches, as it had been in the previous reports, issued at 14 months and two years.

In fact, all four groups had similar improvement in ADHD symptoms at the three-year mark. On average, all still had some symptoms, but not in the severe category.

Some of that "lost ground" with medication "is due to less intense treatment," says Jensen, director of The Reach Institute, a nonprofit organization in New York focused on children's emotional and behavioral health. "It's the only thing that changed [after the 14-month study]."

ADHD Medications Wear Off

In a second report, the researchers tried to figure out why the ADHD medication's effect seems to wear off at the three-year mark, at least for some children. "We analyzed symptoms based on whether or not they were on medication, regardless of what [study] group they were in," says James M. Swanson, PhD, professor of pediatrics at the University of California, Irvine, and a co-author on all four papers.

Still, he tells WebMD, they found at the three-year mark that "all the kids looked better, but the ones taking medication were no better [than the others]."

However, the researchers did find that for a subset of the children, the medication effect seems to kick in at the three-year mark, Swanson says. "These are the kids who initially didn't show a good response [to medication]. They only got a little better the first year but continued to get better over three years."

Of all the children studied, he says, about 34% of them fall into this category, those who do seem to be helped long-term by the drugs. While it's not possible to describe exactly who these children are, Swanson says they tend to be more likely to have other conduct disorders along with the ADHD diagnosis.

ADHD and Risk-Taking Behavior

Another report found that children with ADHD have an increased risk of delinquent behavior, such as stealing or starting fights at school, as well as substance use, such as experimenting with tobacco, alcohol, or illicit drugs. "I don't want people to think these kids are addicts by middle school," says Brooke S.G. Molina, PhD, associate professor of psychiatry and psychology at the University of Pittsburgh and an author of that report. But they were more likely than other children to experiment, she says.

Her team compared delinquency and substance use among 487 children from the MTA study and 272 control students not diagnosed with ADHD. While 27.1% of the ADHD children exhibited delinquent behavior, 7.4% of the comparison group did. Substance use was reported by 17.4% of the ADHD children but 7.8% of the comparison group.

Study Limitations

The study has many limitations, the authors note. The three-year follow-up portion of the study looking at the four treatment approaches did not have an untreated group for comparison. After the first 14 months of the study, children were free to pick and choose among treatments, so the original four treatment groups later received a mix of therapies. Children who took medication for the first 14 months, for instance, may have stopped taking it later.

Some ADHD symptoms may actually subside naturally over time, without treatment, some other research suggests. Experts call this the "clock-setting cure."


Who is at greater risk for developing ADHD? See Answer


Guidance for Parents

The reports are mostly good news, the researchers say. "The main message is, there is improvement [with treatment]," says Benedetto Vitiello, MD, chief of the Child and Adolescent Treatment and Preventive Intervention Research Branch of the National Institute of Mental Health at the National Institutes of Health and a co-author of the studies.

Parents should not ease up or think treatment can become less intensive, however, he adds. "You cannot go on cruise control. The data seem to indicate you will need to continue more intense treatments."

Getting treatment is crucial, adds Molina. "Get treatment that works for you. Treatment helps. This is a chronic disorder, and parents need to view it as that."

"High-quality treatment is really important," Jensen tells WebMD. "You have to be careful to learn what the best treatment is for your child and make sure he gets it for as long as needed."

SOURCES: Peter S. Jensen, MD, director, The Reach Institute, New York City. James M. Swanson, PhD, professor of pediatrics, University of California, Irvine. Brooke S.G. Molina, PhD, associate professor of psychiatry and psychology, University of Pittsburgh. Benedetto Vitiello, MD, chief of the Child and Adolescent Treatment and Preventive Intervention Research Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Md. Jensen, P. Journal of the American Academy of Child and Adolescent Psychiatry, August 2007; vol 46: pp 988-1001. Swanson, J. Journal of the American Academy of Child and Adolescent Psychiatry, August 2007; vol 46: pp 1002-1013. Brooke, S. Journal of the American Academy of Child and Adolescent Psychiatry, August 2007; vol.46: pp 1027-1039.

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