Marked Jump in ADHD Diagnoses

Megan Brooks

January 21, 2013

Rates of childhood diagnoses of attention-deficit/hyperactivity disorder (ADHD) increased markedly in the United States during the last decade, new research shows.

Investigators from Kaiser Permanente Southern California's Department of Research and Evaluation found that rates of ADHD diagnosis increased from 2.5% in 2001 to 3.1% in 2010, a relative increase of 24%.

Dr. Darios Getahun

"This is a significant increase over the 10-year period," lead investigator Darios Getahun, MD, PhD, told Medscape Medical News.

The study also revealed "disproportionately high ADHD diagnosis rates among white children and notable increases among black girls."

"While the reasons for increasing ADHD diagnosis rates are not well understood, contributing factors may include heightened ADHD awareness among parents and physicians as well as increased utilization of screening and other prevention programs," said Dr. Getahun.

The study was published online January 21 in JAMA Pediatrics.

Minority Sex Gap Closing

For the study, researchers examined the electronic health records of 842,830 ethnically diverse children, aged 5 to 11 years, who received care at Kaiser Permanente Southern California between 2001 and 2010.

"We observed wide variation in recent ADHD diagnosis trends by child age, sex, race/ethnicity, and median household income," Dr. Getahun said. "White, black, and Hispanic children were more likely to be diagnosed as having ADHD than Asian/Pacific Islanders and children of other races/ethnicities."

Overall, 39,200 of 842,830 children (4.9%) had a diagnosis of ADHD. In 2010, 5.6% of white children had an ADHD diagnosis, as did 4.1% of black children, 2.5% of Hispanic, and 1.2% of Asian/Pacific Islander children.

As mentioned, the incidence of newly diagnosed ADHD cases rose from 2.5% in 2001 to 3.1% in 2010 (24% relative increase).

Black children showed the greatest increase in ADHD incidence, from 2.6% in 2001 to 4.1% in 2010, a 70% relative increase. The increase in rates of ADHD diagnosis among blacks was largely driven by an increase in girls (90% relative increase), the authors write.

"Although boys were more likely to be diagnosed as having ADHD than girls, results suggest the sex gap for blacks may be closing over time," they note.

ADHD rates among Hispanic children showed a 60% relative increase, from 1.7% in 2001 to 2.5% in 2010. White children showed a 30% relative increase, from 4.7% in 2001 to 5.6% in 2010. Rates for Asian/Pacific Islander children and other racial groups remained unchanged over time.

"The mean age at ADHD diagnosis for Hispanic girls increased during the study period, suggesting a delayed diagnosis," Dr. Getahun reported. Children of parents with high median household incomes were also at increased risk for ADHD diagnosis, he said.

"Serious" Concern

Reached for comment, Joseph Biederman, MD, from the Clinical and Research Program in Pediatric Psychopharmacology and Adult ADHD in the Department of Psychiatry at Massachusetts General Hospital in Boston, told Medscape Medical News there is "nothing particularly surprising" about the study "beyond pointing out that physicians are a bit more willing to diagnose and treat this very morbid and treatable condition, including girls and minorities."

"If anything, the article stresses the very large remaining gap of undiagnosed and untreated children with ADHD that represents, in my opinion, a very serious public health concern," said Dr. Biederman, who was not involved in the study.

Dr. Getahun said the "large amount of missing race/ethnicity data observed in our cohort is a significant limitation. However, sensitivity analyses after classifying children with missing race/ethnicity data in each year to each race/ethnicity group data within the same year yielded similar estimates."

The study was supported by Kaiser Permanente Direct Community Benefit funds. The authors and Dr. Biederman have disclosed no relevant financial relationships.

JAMA Pediatr. Published online January 21, 2013. Abstract