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Study: Childhood Rise in Autism Cases Real

But Reason for the Increase Remains Unexplained
WebMD Health News

March 7, 2005 - Since the 1990s, there's been a dramatic increase in autismautism among school-age children.

The data are from the U.S. Department of Education, and the report hints that the increases seen with time are real.

Research has suggested that the rise in autism could be largely explained by changes in diagnosis, with children who might have been classified as mentally retarded or speech impaired before the 1990s now being classified as autistic.

Lead researcher Craig J. Newschaffer, PhD, says the Department of Education figures do not show this, but he adds that the increase in autism may never be fully understood.

"I don't know if we are ever going to be in a position to explain what has gone on over the last decade," he says. "The hope is that with the surveillance programs that are now in place we will be in a better position to understand future trends."

Earlier findings from the CDC and others have suggested as much as a tenfold increase in autism and related disorders during the last decade of the 20th century.

The study does not answer the question as to why autism is increasing. But the national data don't show a decrease in other learning disabilities. Trends for mental retardation and speech and language impairment remained unchanged.

This suggests the increase in autism is not the result of an across-the-board increase in special education classification, say the researchers.

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