MONDAY, June 25, 2012 (HealthDay News) -- It's better to treat the symptoms of attention-deficit/hyperactivity disorder (ADHD) sooner rather than later to prevent a drop in performance at school, according to new research.
A delay in treatment appeared to make the biggest difference in math scores, and later treatment seemed to affect girls significantly more than boys, the study indicated.
"We found that earlier treatment rather than late may halt declining academic performance, especially in math, and especially for girls," said the study's lead author, Helga Zoega, a postdoctoral fellow at Mount Sinai School of Medicine in New York City, and the Center of Public Health Sciences at the University of Iceland in Reykjavik.
Results of the study were released online June 25, and are scheduled to be published in the July print issue of Pediatrics.
Attention-deficit/hyperactivity disorder affects between 5 percent and 10 percent of all children in the United States and Europe, according to background information in the study. The U.S. National Institute of Mental Health says that the primary symptoms of the disorder are hyperactive and impulsive behavior, and inattention. In general, girls tend to have more trouble with paying attention, while boys tend to be more hyperactive, said Zoega.
Stimulant medications have been shown to have a positive effect on children with ADHD, helping them to focus and helping youngsters control hyperactive and impulsive behavior. However, concerns about overuse, addiction, misuse and unknown long-term outcomes have led some parents to forgo or delay medication use.
To see what effects stimulant treatment had on academic progress, as well as to see if a delay in treatment made a difference, Zoega and her colleagues reviewed data from Iceland's national databases. Iceland retains records on 100 percent of prescription drugs dispensed. They also maintain records on standardized school testing that's required at age 9 and age 12.
The study included data from almost 14,000 Icelandic children born between 1994 and 1996. Data on prescription-medication use were gathered for 2003 through 2008, according to the report.
The researchers identified 1,029 children who were treated with ADHD drugs during the study period. Of those, 96 percent were treated with methylphenidate (brand names Concerta and Ritalin), a stimulant medication.
The academic performance of children without ADHD didn't change much between the fourth and seventh grade tests (given at ages 9 and 12, respectively), the investigators found.
In children who received medication, the researchers noted a decline in academic performance that was concentrated in those who started treatment later. The average decline for those who started treatment later was 9.4 percentage points on the math test, the authors noted. Late treatment was any treatment that began 25 to 36 months after the fourth-grade test.
Overall, those who started treatment late had a 70 percent increased risk of having a decline in math performance between the two tests, and a 10 percent increased risk of having a decline in language arts tests, the investigators found.
Girls who started treatment late had a 2.7 times higher risk of having a decline in their math scores compared to a 40 percent increased risk for boys who started treatment later.
Zoega said the study wasn't designed to look at the reasons behind the decline, but she theorized that the bigger declines in girls' scores with late treatment may be because girls are more likely to have inattention problems, and math skills may be more affected by a lack of focus.
Dr. Andrew Adesman, chief of developmental and behavioral pediatrics at Steven and Alexandra Cohen Children's Medical Center of New York, in New Hyde Park, N.Y., said he wasn't surprised by the study's findings. He said that stimulant medications have been in use since the 1930s, and that back then, children used to refer to the drugs as their "arithmetic pills."
"This study really has bearing for parents of children with ADHD, and they may find some comfort in knowing that there are some academic benefits from treatment with medications, especially if they're started early," Adesman said.
A particular strength of this article is that there was no drug company funding, Adesman said.
Learn more about ADHD from the U.S. National Institute of Mental Health.