Autism in California

Very interesting article highlighting the ever increasing number of autism diagnoses in California.

California's mysterious explosion of autism cases worsened in 2004, disappointing researchers who had hoped the number of new diagnoses would level off as they searched for an explanation for the neurological disorder.

The number of people treated for autism at regional centers operated by the state Department of Developmental Services increased 13 percent last year from 2003, according to agency figures.

The cause is still a mystery.

Robert Byrd, a pediatric epidemiologist at UC Davis who was the lead investigator in a study of a 10-year increase in autism cases in California through 1998, said researchers have looked into several theories to explain the increase. They include the possibility that the rising autism numbers were caused by improved and earlier diagnoses, or by childhood vaccines or other environmental causes.

Most researchers believe genetics play a role, but they aren't sure what spurs the disorder. None of the other theories has been proved or ruled out.

"There is no one answer that says we can explain what we're seeing," Byrd said. "We're still looking at these numbers with lots of questions."

If vaccines played a role, said Byrd, scientists would have seen a decline or leveling off in cases after a suspect preservative containing mercury was removed from childhood immunizations. No such decrease was noted.

The state has used new, stricter criteria since 2003 for diagnosing autism, but that also has not made a difference. The number of new cases of mental retardation and cerebral palsy -- which also are diagnosed using new criteria -- fell since 2003.

Byrd and others say a greater awareness of autism may account for some of the increase. Parents, pediatricians and schools now recognize the symptoms earlier and refer children for treatment. But that doesn't completely explain the increase, they believe.