More on the study

What is ADHD?

It is a set of disorders characterized by attention problems of a disorganized and daydreamy "inattentive" type, an impulsive, talking-all-the-time "hyperactive" type or a combination of both.

Key findings of the original Johnston County study

About 10 years ago, researchers asked Johnston County families of 7,333 children in grades 1 through 5 to participate in an ADHD study. About 6,099 - or 83 percent of those asked - agreed. The researchers went a step further, doing in-depth interviews or questionnaires with parents and teachers of about 1,160 children.

- According to their parents, about 10 percent, or 607, of the elementary school students had been previously diagnosed with ADHD by a health professional. (In a smaller study done the year before on 424 children, the researchers estimated the prevalence of ADHD in Johnston County elementary school children was 16 percent when they combined symptom information from parents and teachers, rather than parent reports of previous ADHD diagnosis.)

- Parents reported that 7 percent, or 434, of the children were taking a stimulant medication to treat ADHD.

- Among those diagnosed with ADHD, Caucasian children were more likely to receive treatment than African-American or Hispanic children. Researchers said less access to health insurance, less ability to pay for medication or cultural differences in acceptance of treatment may have been factors.

What the new study will examine

- How ADHD affects young adults of different sexes, races and economic backgrounds.

- How well medications work over time, affecting areas like grades, sleep and ability to make friends or get along with family members.

- Whether ADHD youth are more likely to engage in risky behaviors, such as smoking, drinking and unsafe sex.

How the studies affect Johnston County schools

Concerned that screening all children for ADHD would become a large burden on the schools, the school system and researchers teamed up to win a $500,000 grant shortly after the original study began, to train parents, teachers and medical workers in dealing with ADHD. About 400 ADHD students were evaluated and helped through an ADHD clinic over several years.

"This was very successful," said Keith Beamon, an associate superintendent of Johnston County Schools. "We still use some of the educational materials that were purchased as we work with parents."

A grant tied to the new study will support additional education and training for Johnston County school psychologists in the area of ADHD.