Newswise — In an 18-year-study on attention-deficit/hyperactivity disorder (ADHD), Mayo Clinic researchers found that treatment with prescription stimulants is associated with improved long-term academic success of children with AD/HD. The Mayo Clinic results are the first population-based data to show stimulant drug therapy helps improve long-term school outcomes.

A related Mayo Clinic study reveals that compared to children without ADHD, children with AD/HD are at risk for poor long-term school outcomes such as low achievement in reading, absenteeism, repeating a grade, and dropping out of school. Both studies appear in the current edition of the Journal of Development & Behavioral Pediatrics.

Nearly 2 million children, or approximately 3 percent to 5 percent of young children in the United States, are estimated to have AD/HD. This disorder affects a child’s ability to focus, concentrate and control impulsive behavior (see This disorder is so common that most school classrooms have at least one child with clinically-diagnosed AD/HD.

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

The two Mayo Clinic studies are the first population-based, long-term studies to investigate links between AD/HD, school performance and factors that modify long-term school performance of children with AD/HD. Researchers followed the children from the time they were born for, on average, 18 years. Of the more than 5,000 children evaluated, 370 (277 boys and 93 girls) were identified as having ADHD. Researchers matched them by age and gender to 740 children who did not meet the research criteria for having AD/HD. In addition to medical stimulants such as methylphenidate, also called Ritalin, 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 indicate that girls and boys with untreated AD/HD were equally vulnerable to poor school outcomes — and girls may be at risk for being under-identified as having AD/HD, and therefore 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 AD/HD who were treated with stimulants were 1.8 times less likely to be retained a grade than children with AD/HD who were not treated.

Dr. Barbaresi believes that both studies provide the first solid evidence of the long-term negative academic performance associated with untreated ADHD — as well as evidence for the best way to manage this problem. Dr. Barbaresi says, “The finding that treatment with stimulant medications is associated with long-term improvement in school outcomes is significant. Previously, there was evidence that treatment with stimulant medications improved short-term academic performance, but there was no good evidence that long-term outcomes are better with stimulant treatment. Our data can guide clinicians in their efforts to help children with AD/HD succeed in school.”