Proposed revisions in the manual that doctors use to diagnose mental illness would streamline autism criteria. Critics contend the suggested changes would be too narrow and exclude children who need educational and behavioral services.
Hyman noted that since the manual's last revision, in 1994, much has been learned about autism. "There's a real possibility the new definition will be better for children," she said Thursday at a CDC news conference.
CDC officials say research into causes of autism will help determine if there's been a true increase or just better diagnosis.
Genetics is believed to play a role. Studies have found no connection with childhood vaccines, but other factors under investigation include mothers' illnesses or medication during pregnancy. First results from the CDC study are expected next year.
Geraldine Dawson, chief science officer for the advocacy group Autism Speaks, said the new figures indicate "a public health emergency that demands immediate attention."
Her group estimates that U.S. autism costs total $126 billion each year, including costs related to diagnosis and treatment. That estimate also includes treatment for severely affected adults and lost wages.
Autism Speaks: http://www.autismspeaks.org
AP Medical Writer Mike Stobbe in Atlanta contributed to this report.
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