A new study suggests the idea that more kids are being diagnosed with autism not because something catastrophic has happened to U.S. children, but rather because they're simply being classified and diagnosed differently.
Special education enrollment figures suggest 97 percent of the increase in autism seen between 2000 and 2010 could simply be accounted for by reclassification — at least among older kids — a team at Penn State University found.
Overall, two-thirds of the increase could be due to reclassification, the researchers reported in the American Journal of Medical Genetics.
Their conclusions won't end the debate, but they may offer some solace to worried parents and help explain such a huge jump in cases. The Centers for Disease Control and Prevention found a 30 percent spike in autism diagnoses among 8-year-olds between 2008 and 2010 to one in 68 children.
Santhosh Girirajan, an assistant professor of biochemistry and molecular biology and of anthropology at Penn State and colleagues looked at 11 years of special-education enrollment data covering more than 6 million children a year. They found that the increase in students designated as having autism could be offset by a nearly equal decrease in students diagnosed with other intellectual disabilities often seen along with autism.
This suggests that special education experts, doctors and other medical specialists are choosing to designate more conditions as autism — possibly because of wider awareness about and acceptance of the condition.
"For quite some time, researchers have been struggling to sort disorders into categories based on observable clinical features, but it gets complicated with autism because every individual can show a different combination of features," Girirajan said in a statement.
"The tricky part is how to deal with individuals who have multiple diagnoses because, the set of features that define autism is commonly found in individuals with other cognitive or neurological deficits."
Autism spectrum disorder can range from mild symptoms to profound mental retardation, debilitating repetitive behaviors and an inability to communicate. Genes have a strong influence and autism runs in families.
There's no cure, but experiments with early treatment suggest it might be possible to help children overcome some difficulties.
"Every patient is different and must be treated as such," said Girirajan.