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Autism may be overdiagnosed in as many as 9 percent of children, U.S. government researchers reported Friday.

It might be because autism covers such a broad range of symptoms and behaviors and is difficult to diagnose, and it may also be because increasing awareness about autism means there are resources to help kids who get the diagnosis, the team at the Centers for Disease Control and Prevention and the University of Washington found.

A girl plays with soap bubbles during a charity event for children with autism in a park in Kiev, Ukraine, on May 28, 2015. SERGEI SUPINSKY / AFP - Getty Images

The survey also suggests that up to 4 percent of children are helped with early therapy, or outgrow their symptoms, Stephen Blumberg of the National Center for Health Statistics and colleagues found.

“The results of this study suggest that some children with developmental delays, attentional flexibility problems, or other conditions may be receiving provisional yet inaccurate diagnoses of autism spectrum disorder from nonspecialists,” they wrote in their report, published in the journal Autism.

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It fits in with what other researchers have found.

The CDC found a 30 percent spike in autism diagnoses among 8-year-olds between 2008 and 2010 to one in 68 children. It was a startling finding and one that fueled fears that something was causing more children to develop the condition.

But a report published earlier this year suggested that many cases of developmental delays had simply been re-classified as autism in recent years.

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.

Blumberg’s team followed up on a national survey of more than 1,500 parents of kids with autism.

“Approximately 13 percent of the children ever diagnosed with autism spectrum disorder were estimated to have lost the diagnosis, and parents of 74 percent of them believed it was changed due to new information,” Blumberg’s team wrote.

This means 9 percent of the children originally diagnosed with autism got that diagnosis changed. Many got a new diagnosis of attention deficit/hyperactivity disorder or ADHD, the researchers found.

“It is possible this is the result of the high overlap between the symptoms of these disorders,” they wrote.

It’s possible that language and developmental delays look like autism, and it’s also possible that kids with other learning disabilities are given an autism diagnosis because services are more available in some places for children with autism, they said.