WASHINGTON — Centers for Disease Control and Prevention's National Center for Health Statistics official report the rates of attention-deficit/hyperactivity disorder (ADHD) in US children continue to trend upward.
However, Mexican children had consistently lower ADHD prevalence than other racial or ethnic groups.
According to Lara J. Akinbami, MD, and colleagues, the percentage of American children diagnosed as having ADHD increased from 6.9% in 1998-2000 to 9.0% in 2007 to 2009.
From 1998 through 2009, ADHD prevalence was higher among boys than girls. For boys, ADHD prevalence increased from 9.9% in 1998-2000 to 12.3% in 2007-2009 and for girls from 3.6% to 5.5% during the same period.
ADHD prevalence varied by race and ethnicity, but differences between most groups narrowed from 1998 through 2009, the study authors note.
For non-Hispanic white children, ADHD prevalence increased from 8.2% in 1998-2000 to 10.6% in 2007-2009 and from 5.1% to 9.5% for non-Hispanic black children.
From 1998 through 2009, ADHD prevalence increased to roughly 10% among children with family income less than 100% of the poverty level and to 11% for those with family income between 100% and 199% of the poverty level.
The report also shows regional differences in ADHD prevalence. In the Midwest, ADHD prevalence rose from 7.1% in 1998-2000 to 10.2% in 2007-2009. In the South, rates rose from 8.1% to 10.3% for the 2 periods.
In 1998-2000, ADHD prevalence was higher in the South region than in all other regions. In 2007-2009, ADHD prevalence was similar in the South and Midwest regions; prevalence in these 2 regions was higher than in the Northeast and West regions, the report indicates.
Dr. Akinbami and colleagues note that these prevalence estimates "are based on parental report of the child ever receiving a diagnosis and thus may be affected by the accuracy of parental memory (including recall bias), by differential access to healthcare between groups (diagnostic bias), or by willingness to report an ADHD diagnosis."
They also point out that it was not possible to discern whether rising prevalence of ADHD "indicates a true change in prevalence or increased detection and diagnosis of ADHD."
Nevertheless, the societal costs of ADHD — including those associated with medical, educational, and criminal justice resources — are large, they write.
ADHD is one of the most common mental health disorders of childhood. Hallmark symptoms, including difficulty staying focused and controlling behavior, begin in childhood and often persist into adulthood, leading to functional impairment in academic, family, and social settings. The causes and risk factors are unknown, but genetic factors likely play a role.