ADHD Medication Doesn't Work on Some Preschoolers

Children diagnosed with Attention Deficit/Hyperactivity Disorder (ADHD) may not respond to methylphenidate, otherwise known as brand name Ritalin, if the child suffers from other behavioral and social disorders. The number of coexisting conditions can diminish the effectiveness of the medication, according to a new look at a study from the National Institutes of Health's National Institute of Mental Health (NIMH).

The Preschoolers with ADHD Treatment Study (PATS) was released last October, and showed that young children between the ages of 3 and 5 who were diagnosed with ADHD responded well to doses of methylphenidate. However, a new article published in the latest issue of the Journal of Child and Adolescent Psychopharmacology reports that the effectiveness of methylphenidate lessens if the child has other disorders, such as anxiety disorders, conduct disorder, and/or oppositional defiant disorder.

The data from the PATS showed out of the 165 children that were part of the original study group, 71 percent of the participants had one to three other disorders in conjunction with ADHD. Depending on the number of other disorders involved, the efficacy of the medication was decreased. Children with only one other disorder may not respond as well as those children with no other disorders, but the children with three disorders did not respond at all to the methylphenidate.

The researchers found no corresponding decreases in efficacy when demographics were examined, such as gender or ethnicity. But there is some correlation between socio-economic factors and the number of disorders a child may have. Children with three or more disorders were found to be more likely to come from poorer households, and usually a single-parent household.

This new article is not entirely a shock to anyone working on this study. In a NIMH study on the Multimodal Treatment Study of Children with Attention Deficit Hyperactivity Disorder, it was found that children that suffered from other disorders could not rely on medication alone to relieve ADHD symptoms.

Methylphenidate is the most common medication to treat ADHD in young children. ADHD is usually diagnosed between the ages of 3 and 5, so treatment during that time is of considerable concern for parents, physicians, and researchers. Until the PATS study, there were no major studies into the effectiveness of treatment options on preschool age children.

Dr. Thomas R. Insel, the NIMH Director, said in the NIH press release that the new data sheds light on how physicians can work with different treatment options to help their younger patients. He added, "It also identifies a group of young children who have significant and multiple problems, and for whom more research is needed to identify effective treatments."

In addition to the article just published on this subject, there are other articles in the same issue of the Journal of Child and Adolescent Psychopharmacology that address the effectiveness of methylphenidate on other aspects of the children undergoing treatment.

Sources: National Institutes of Health, National Institute of Mental Health