That may be a myth.
A study published in The Journal of Clinical Psychiatry on Tuesday shows a surprising 55 percent increase in prevalence of diagnoses among girls – from 4.7 percent to 7.3 percent from 2003 to 2011.
The rise in cases in girls mirrors a similar but less-sharp rise in cases in boys from a prevalence of 11.8 to 16.5 percent. During the same period, the researchers found an increase in cases across all races and ethnicities but especially in Hispanic children. In all children, the prevalence increased from 8.4 percent to 12 percent.
The analysis, conducted by George Washington University biostatistician Sean D. Cleary and his co-author Kevin P. Collins of Mathematica Policy Research, was based on data from the National Survey of Children’s Health in which parents were asked whether they had been told by a doctor or other health care provider that their child has ADHD.
ADHD is generally thought to be more difficult to diagnose in girls than boys because the condition manifests itself differently. A boy with ADHD may show more symptoms that are “external,” clinicians suggest, so a boy may yell or shout in certain situations whereas a girl may resort more to teasing or name-calling, or a boy may be more vocal about not being able to finish a task whereas a girl might internalize her frustration.
The study is believed to be among the first to look at the change in ADHD diagnoses across racial and ethnic lines.