Treatment with prescription stimulants is associated with improved long-term academic success of children with attention deficit hyperactivity disorder, according to results of an 18-year study published in the August issue of the Journal of Development & Behavioral Pediatrics.

In the first population-based, long-term study on possible links between the disorder, school performance, and other factors that modify long-term school performance, Researchers followed children from the time they were born for an average of 18 years.

Of the more than 5,000 children evaluated, 370 (277 boys, 93 girls) were diagnosed with the disorder. Researchers matched them by age and gender to 740 children who did not meet diagnostic criteria. In addition to medical stimulants such as methylphenidate, the study examined the effects on school outcomes of maternal age, socioeconomic background, and special education services the students received.

The children treated with stimulants typically began taking medication in elementary school and received it for nearly three years -- on average, for 30.4 months. Results indicated that untreated girls and boys were equally vulnerable to poor school outcomes. In addition, there were suggestions that girls may be at risk for being under-identified, and, hence, undertreated.

By age 13, on average, stimulant dose was modestly correlated with improved reading achievement scores. Both treatment with stimulants and longer duration of medication were associated with decreased absenteeism. Children with the disorder who were treated with stimulants were 1.8 times less likely to be retained a grade than untreated children with the disorder.

A related study revealed that compared with children without the disorder, affected children were at risk for poor long-term school outcomes such as low achievement in reading, absenteeism, repeating a grade, and dropping out of school. The second study is in the same journal issue.

Nearly 2 million children, or approximately 3 percent to 5 percent of young children in the United States, have been diagnosed with the disorder.

“In this study, treatment with stimulant medication during childhood was associated with more favorable long-term school outcomes,” said William Barbaresi, MD, Mayo Clinic pediatrician and lead author of the reports.