Twelve percent of U.S. children and teens had a diagnosis of Attention Deficit/Hyperactivity Disorder (ADHD) in 2011, a number that has jumped by 43 percent since 2003, according to a large national study based on parental reports of an ADHD diagnosis. This analysis suggests that 5.8 million U.S. children ages 5 to 17 now have this diagnosis, which can cause inattention and behavioral difficulties, says lead researcher Sean D. Cleary, PhD, MPH, an associate professor of epidemiology and biostatistics at Milken Institute School of Public Health (Milken Institute SPH) at the George Washington University.

The research also uncovered a surprising increase in ADHD among girls during the study time frame. “We found the parent-reported prevalence for girls diagnosed with ADHD rose from 4.3 percent in 2003 to 7.3 percent in 2011. That’s an increase of 55 percent over an eight year period,” Cleary says, adding: “Traditionally, boys have been more likely to get a diagnosis of ADHD.”

The report, published online today in The Journal of Clinical Psychiatry, was based on data sponsored by the Maternal and Child Health Bureau and the National Center for Health Statistics of the U.S. Centers for Disease Control and Prevention in a National Children’s Survey from 2003-2011. Cleary and his co-author Kevin P. Collins of Mathematica Policy Research mined the data looking for trends in parent-reported prevalence of ADHD.

“We found rising rates of ADHD overall and very sharp jumps in certain subgroups,” Cleary said, adding that for adolescents the diagnosis jumped by 52 percent since 2003. “Parents should be made aware of the findings in case they have a child or teenager that should be evaluated for the disorder, which can persist into adulthood.”

This study was not designed to look at the underlying reasons for such changes in prevalence, Cleary said. The reported increase in the diagnosis could be a true increase in the number of ADHD diagnoses or it could be the result of a tendency to over-diagnose the condition. Additional research will need to be done to find out why there has been a rise in the diagnosis, with special attention being paid to certain groups, Cleary said.

Cleary and Collins looked at data taken from the National Survey of Children’s Health, a nationally representative cross-sectional survey that collected information on the health of children aged 17 and younger. They focused on a question in the survey that asked parents if a doctor or another health care provider had told them that their child had ADHD. The researchers also kept track of race/ethnicity and whether the children were boys or girls and other relevant sociodemographic factors that have previously been found to be related to ADHD diagnosis.

There have been very few previous studies looking at the prevalence of this disorder among different racial or ethnic groups, Cleary said. This study did hone in on such subgroups finding the prevalence of parent-reported ADHD had risen by about 83 percent in Hispanic youth during the eight year study period. “Additional studies must be done to identify the underlying cause of the increase,” Cleary says. In the meantime, he says that parents should be aware of all of the issues surrounding a diagnosis of ADHD and talk to their doctor if they have concerns about a child’s ability to focus or behavior.

The question of why the condition seems to be increasing is important because the diagnosis often comes with a prescription for a stimulant drug like Ritalin. Such drugs can help children and adults with ADHD focus and stay on task. However, critics worry that the drugs may be over-prescribed.

Children with ADHD may have trouble with paying attention in class or at home and they might also be impulsive or prone to making careless mistakes. They can also be forgetful and, if nothing is done, the condition can lead to difficulties at school, at home and in social situations, according to U.S. Centers for Disease Control and Prevention.