White Children More Likely To Get Stimulants for ADHD

Researchers are hopeful that as they continue to analyze data from a community sample of children with attention-deficit/hyperactivity disorder (ADHD), they will learn more about diagnostic criteria and treatment outcomes.

Researchers at the National Institute of Environmental Health Sciences (NIEHS) and colleagues at the University of North Carolina at Chapel Hill surveyed the parents of all public elementary school children in Johnston County, N.C., from 1997 to 1999.

The NIEHS is a branch of the National Institutes of Health located in Research Triangle Park, N.C., which is close to Johnston County.

More than 80 percent of parents returned the survey; the results appear in the February American Journal of Public Health.

The parental surveys revealed that a physician or psychologist had diagnosed 607 of the 6,099 children in the sample, or 10 percent, with ADHD. All of the children in the sample were first- to fifth-graders at one of the 17 public elementary schools in the county.

Of the total sample, 7 percent, or 434, were taking a medication for their ADHD symptoms. Most of the medications—93 percent—were stimulants, and about 10 percent of children taking a stimulant were also taking at least one other medication. The other medications included adrenergic receptor agents such as clonidine or guanfacine, antidepressants, and mood stabilizers.

Principal investigator Andrew Rowland, Ph.D., analyzed the data to explore how treatment with medication differed by the gender, age, and ethnicity of the elementary-school children.

Rowland, who has moved from the NIEHS to the University of New Mexico Health Sciences Center, where he is an assistant professor in the Master of Public Health Program in the school’s department of family and community medicine, found that overall, the older white boys in the sample were most likely to receive medication.

The survey did not inquire about information on other forms of treatment for ADHD, such as behavioral therapy.

When Rowland and his colleagues looked at the gender of the children who received treatment, he found that 11 percent of boys in the total sample took stimulant medication for ADHD, while just 3 percent of girls did, a ratio also found in other studies, Rowland noted.

Treatment rates were considerably higher for the older children in the sample. For instance, 62 of the 1,425 children in first grade, or or 4.4 percent, took stimulant medications for ADHD, compared with 87 of the 945 children in fifth grade, or about 9 percent.

The surveys also revealed discrepancies between how often white children received stimulant medication for ADHD compared with minority children. Even though white and African-American children were diagnosed at similar rates, 8.2 percent of the 4,437 white children (364) took medications to relieve symptoms of ADHD, while 5 percent of the 1,208 African-American children (62) did. White boys in the fourth and fifth grades had the highest treatment rates, with more than 15 percent (123 of 800) taking stimulant medication.

According to Rowland, the lower medication-treatment rates for minorities are likely due to the fact that many minorities have poorer access to medical care and less insurance coverage than whites. “There may also be cultural differences in the willingness of some minority families to have a child be treated for behavioral problems with medications,” he said.

Rowland and his colleagues suggested that the numbers of children who are diagnosed and treated for ADHD in Johnston County may not be unusual for other counties in North Carolina. “We think that Johnston County is similar to many other counties in North Carolina in terms of the number of physicians per person living in the county, urban and rural characteristics, the distribution of wealth, education levels, and ethnic profiles,” said Rowland. “However, similar studies would need to be conducted to know for certain whether these findings could be replicated in other areas of the state.”

Rowland said that the strength of the Johnston County study lies in the survey design. “The study provides a good estimate of ADHD medication treatment in one county because parents, as opposed to school officials, are being surveyed about medications taken by children. . . . School-based data are biased toward undercounting the true prevalence of medication treatment,” he said.

He explained that school nurses, for instance, when asked whether students are taking medications for ADHD, don’t know about, and thus don’t report, the use of long-acting stimulants, which some children take at home before they go to school.

The findings from the Johnston County study left researchers thirsting for more information. “There have not been adequate long-term studies on the effectiveness or the safety of ADHD medication treatment using community-based samples,” Rowland said, adding that these data should be collected in representative samples of the entire United States population.

Rowland is now analyzing additional data collected in the Johnston County study to determine how many children in Johnston County meet DSM-IV criteria for ADHD and how well medication treatment is working for the children in the study.

An abstract of the study, “Prevalence of Medication Treatment for Attention-Deficit/Hyperactivity Disorder Among Elementary School Children in Johnston County, North Carolina,” is posted on the Web at www.ajph.org/cgi/content/abstract/92/2/231. ▪