White children from high-income homes are most likely to be diagnosed with attention-deficit hyperactivity disorder, as more children overall are getting a diagnosis of ADHD, according to a study released Monday that looked at hundreds of thousands of California medical records.
The study, published online in JAMA Pediatrics, found that 4.9 percent of children treated through insurer Kaiser Permanente Southern California were diagnosed with ADHD during the decadelong study. The figure is slightly lower than government and other estimates that suggest almost 10 percent of school-age children have the disorder. But it matches other studies showing a significant rise in the rate of first-time ADHD diagnosis for children.
ADHD is the most common neurobehavioral disorder in children. The condition is often marked by the inability to focus or pay attention, hyperactivity and impulsive behavior. To be diagnosed with ADHD, the problems need to be so frequent that they interfere with the child's ability to adequately function on a daily basis without treatment.
The study, which involved nearly 850,000 medical records of children between 5 and 11 years old in Kaiser's database, found that 3.1 percent received a first-time diagnosis of ADHD in 2010, up from 2.5 percent in 2001. Children in higher-income homes, defined as those with annual income above $70,000, were the subset most likely to be diagnosed, but researchers also found notable increases among black girls. The highest rates were observed in children with household incomes of $90,000 or more.
Between 2001 and 2010, the rate of ADHD increased to 5.6 percent from 4.7 percent for whites, to 4.1 percent from 2.6 percent for blacks and to 2.5 percent from 1.7 percent for Hispanics.
The study showed 1.2 percent of children with Asian or Pacific Islander backgrounds were diagnosed with ADHD in 2001, a rate that stayed constant over the decade.
Darios Getahun, a scientist at Kaiser Permanente Southern California, said people of Asian background historically have been reluctant to seek out mental-health services, while higher-income white parents may be more likely to get help for children who aren't meeting academic expectations.
The strength of the study is that it used detailed electronic medical records to confirm the ADHD diagnoses, the bulk of which were made by specialists rather than primary-care doctors. Many other estimates of ADHD come from parent and teacher surveys, which are considered less accurate.
Study researchers and doctors who treat ADHD say that increased diagnosis—not necessarily a change in the prevalence of the ailment—is a big factor behind the rising rates of the disorder. But research hasn't ruled out the possibility of other factors at play.