But some question accuracy of estimate
WebMD News from HealthDay
By Dennis Thompson
HealthDay Reporter
TUESDAY, March 3, 2015 (HealthDay News) -- About 7 percent of children worldwide have attention-deficit/hyperactivity disorder (ADHD), new research concludes.
This estimate -- which differs significantly from other recent appraisals -- is based on data from 175 prior studies conducted over nearly four decades.
The approximation could help public health officials determine whether ADHD is overdiagnosed or underdiagnosed in their nation, state or community, said lead author Rae Thomas, of Bond University in Australia.
"Prevalence estimates act as an anchor," said Thomas, a senior research fellow at the university's Center for Research in Evidence-Based Practice. "When people hear that number, they think, 'This is much more or much less common than we thought.' How common a condition is may impact how clinicians view symptoms."
The estimate comes in lower than the latest data from the U.S. Centers for Disease Control and Prevention, which reports that 11 percent of U.S. school-age children had been diagnosed with ADHD by 2011.
However, it is double a worldwide ADHD estimate of 3.4 percent published in the Journal of Child Psychology and Psychiatry earlier this year, in a study that used very different methods, Thomas noted.
Critics say there may be serious problems with the way Thomas and her colleagues came to their conclusions, noting the research pools together dozens of studies that used a wide variety of criteria to determine whether children had ADHD.
For example, the study pools prior results based on diagnostic criteria that varied among three versions of the Diagnostic and Statistical Manual of Mental Disorders, the "bible" used by mental health professionals, said Dr. Eyal Shemesh, chief of behavioral and developmental health at the Kravis Children's Hospital at Mount Sinai in New York City.
"The authors' own results establish that there is a wide variability in estimates based on several issues, including the setting of the research and the evaluation method that is used," Shemesh said.
"If this is so, then any attempt to look at a specific community in relation to the pooled estimate would be wrong," Shemesh said.
source : About 7 Percent of Kids Worldwide Have ADHD: Study
