(Reuters Health) – More than 10 percent of U.S. children have
been diagnosed with attention deficit hyperactivity disorder (ADHD), reflecting
a surge in recent years particularly among girls and minority groups, a new
study finds.

Spikes in diagnoses among girls, Hispanics and older kids may be
the result of better screening and monitoring among previously under diagnosed
groups, experts say.

Roughly 5.8 million children aged five to 17 years are now
diagnosed with ADHD, which is characterized by social and behavioral problems
as well as challenges in school, according to the analysis of cases reported by
parents from 2003 to 2011.

Diagnosis rates jumped 43 percent overall during the study
period, from 8.4 percent of children in 2003 to 12 percent by 2011.

Over that time, diagnosis among girls jumped 55 percent from 4.7
percent in 2003 to 7.3 percent in 2011, though prevalence remained higher among
boys.

“The sharper increase among girls was a surprise primarily
because ADHD is typically diagnosed among boys,” said study co-author Sean
Cleary, a public health researcher at George Washington University in
Washington, D.C.

“One possibility to explain the increasing trend among females
is a greater recognition of ADHD symptoms observed (e.g. withdrawn,
internalizing) that are traditionally overlooked because they are not typically
considered a sign of this condition,” Cleary added by email.

To assess shifts in diagnosis patterns over time, Cleary and
co-author Kevin Collins of Mathematic Policy Research analyzed data on more
than 190,000 children from U.S. surveys conducted in 2003, 2007 and 2011.

As part of the surveys, parents reported whether their child had
been diagnosed with ADHD.

Boys accounted for the majority of cases, and diagnosis for them
rose 40 percent during the study period to 16.5 percent by 2011.

Age also played a role in diagnosis rate gains, with the a 33
percent increase among kids aged five to nine years old, a 47 percent climb for
those 10 to 14 years, and a 52 percent surge for teens 15 to 17 years.

While white children still made up the majority of cases,
diagnosis rates climbed much more for black and Hispanic youth, according to
the results in the Journal of Clinical Psychiatry. In particular, diagnosis
among Hispanic children spiked 83 percent over the study period. For blacks,
diagnoses rose 58 percent.

Shortcomings of the study include low response rates and its
reliance on data from telephone surveys that didn’t include mobile numbers
until 2011, the authors note.

Still, the rising diagnosis rates aren’t surprising, and are
consistent with trends U.S. clinicians have been seeing for years, said Quyen
Epstein-Ngo, a psychology researcher at the University of Michigan in Ann Arbor
who wasn’t involved in the study.

It’s possible that some of the increase in diagnosis is due to
some children having avoided diagnosis in the past as a result of having less
severe symptoms, more coping strategies or a stronger support system to help
them deal with the demands of school, Epstein-Ngo said by email.

“It could be that the last several years have seen an increased
ability, or willingness, to recognize that older adolescents who are still
struggling could require more formal help and support,” Epstein-Ngo said.
“Alternatively, it could be that increased pressures on adolescents to perform
and achieve are leading to a push for more ADHD assessments.”

Some previous research has also raised concerns that children
from certain minority groups may have been underdiagnosed in the past, noted
Dr. Timothy Wilens, chief of child and adolescent psychiatry at Massachusetts
General Hospital and Harvard Medical School in Boston.

The surge in diagnosis for some non-white students in the study
“may reflect appropriately increased testing and evaluation of academic and
interpersonal difficulties,” Wilens, who wasn’t involved in the study, said by
email.

Even though the data point to rising ADHD diagnosis rates,
Wilens cautioned, the study based on parents’ responses to a single survey
question doesn’t help answer why children were diagnosed or what treatment they
may have received.

“I do believe these data indicate that adolescents, girls, and
certain racial ethnic groups are being monitored more stringently for
behavioral and academic difficulties including ADHD and other problems,” Wilens
added.