This may be the reason most of those newly diagnosed children tend to have milder forms of autism, Blumberg said.
"It would certainly make sense that those with unrecognized autism spectrum disorder may have symptoms that are milder than children who have been diagnosed earlier," he said.
Rosanoff agreed that more children with milder autism are being diagnosed.
"What we are seeing is that children who have not been diagnosed in the past are now being diagnosed," he said. "That is likely due to doctors and other health care providers being better at recognizing the more milder symptoms of autism and being able to diagnose those."
These children are most likely having trouble with social skills, which limits their ability to interact with others in the classroom and in social situations, Rosanoff said.
Diagnosing these children is important, Rosanoff said, because even though they may be doing well in the classroom they could benefit from help with their autism.
"With appropriate diagnosis and access to services, a child with autism can improve in the way they function and how they are able to be successful in life," he said.
To reach their conclusions, researchers gathered data from the National Survey of Children's Health, which is a national telephone survey of nearly 96,000 American households. As part of the survey, parents are asked whether they have a child diagnosed with autism.
For more on autism, visit Autism Speaks.
SOURCES: Stephen Blumberg, Ph.D., senior scientist, National Center for Health Statistics, U.S. Centers for Disease Control and Prevention; Michael Rosanoff, M.P.H., associate director, Pu
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