The rate of children diagnosed with Attention Deficit Hyperactivity Disorder rose dramatically between 2001 and 2010 with non-Hispanic white children having the highest diagnosis rates, according to a Kaiser Permanente study published in the journal JAMA Pediatrics (formerly Archives of Pediatrics and Adolescent Medicine). The study also showed there was a 90 percent increase in the diagnosis of ADHD among non-Hispanic black girls during the same nine-year period.
The study examined the electronic health records of nearly 850,000 ethnically diverse children, aged 5 to 11 years, who received care at Kaiser Permanente Southern California between 2001 and 2010. It found that among these children, 4.9 percent, or 39,200, had a diagnosis of ADHD, with white and black children more likely to be diagnosed with the neurobehavioral disorder than Hispanics and Asian/Pacific Islander children. For instance, in 2010, 5.6 percent of white children in the study had an ADHD diagnosis; 4.1 percent of blacks; 2.5 percent of Hispanics; and 1.2 percent of Asian/Pacific Islanders.
The study also examined increases in the rates of first-time ADHD diagnosis. Researchers found that the incidence of newly diagnosed ADHD cases rose from 2.5 percent in 2001 to 3.1 percent in 2010 - a relative increase of 24 percent. Black children showed the greatest increase in ADHD incidence, from 2.6 percent of all black children 5 to 11 years of age in 2001 to 4.1 percent in 2010, a 70 percent relative increase. Rates among Hispanic children showed a 60 percent relative increase, from 1.7 percent in 2001 to 2.5 percent in 2010. White children showed a 30 percent relative increase, from 4.7 percent in 2001 to 5.6 percent in 2010, while rates for Asian/Pacific Islander children and other racial groups remained unchanged over time.
"Our study findings suggest that there may be a large number of factors that affect ADHD diagnosis rates, including cultural factors that may influence the treatment-seeking behavior of some groups," said study lead author Darios Getahun, MD, PhD, from Kaiser Permanente Southern California's Department of Research & Evaluation. "These findings are particularly solid given that our study relied on clinical diagnoses of ADHD based on the criteria specified within the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders and that it represents a large and ethnically diverse population that can be generalized to other populations."
In addition, the study found that boys were three times more likely to be diagnosed with ADHD than girls. Higher family incomes also were associated with the likelihood of ADHD diagnosis; children from families with a household income of more than $30,000 a year were nearly 20 percent more likely to be diagnosed with ADHD than children from families making less $30,000.
According to the Centers for Disease Control and Prevention, ADHD is one of the most common neurobehavioral disorders of childhood. The CDC estimates that between 4 percent and 12 percent of school-aged children have the disorder, which generates health care costs of between $36 billion and $52 billion per year. Children with ADHD are more likely to experience learning problems, miss school, become injured and experience troublesome relationships with family members and peers, according to the researchers.