The study suggests the increase may be influenced by racial, ethnic, and economic factors.
The report is published in the National Center for Health Statistics Data Brief for August 2011.
ADHD is one of the most common mental health disorders of childhood, but its frequency varies by race and ethnicity, the CDC says.
Symptoms of ADHD include inattention, impulsive behavior, and hyperactivity.
Race, Ethnicity, and Income Factors in ADHD Diagnosis
The CDC, analyzing trends in children age 5 to 17, says that between 1998 and 2009:
- ADHD prevalence increased to 10.3% for children with family incomes of less than 100% of the poverty level, up from 7%, and to 10.6% for those with family incomes between 100% and 199% of the poverty level, compared to 7% in the earlier period.
- ADHD prevalence rose from 8.2% to 10.6% for non-Hispanic whites during the period studied, and from 5.1% to 9.5% for non-Hispanic black youngsters.
- ADHD frequency rose to 10% in the Midwest and South. The frequency of ADHD in these two regions was higher than in the Northeast and West.
- Mexican-American children consistently have had lower percentages of ADHD than other racial or ethnic groups.
- ADHD frequency was higher among boys than girls. For boys, it increased from 9.9% in the 1998-2000 period to 12.3% in 2007-2009. In girls, frequency rose from 3.6% to 5.5%.
ADHD estimates in the report are based on a survey of parents who reported if their child had ever received a diagnosis of ADHD, the CDC says.