Amy Harmon writes at The New York Times:
THE report by the Centers for Disease Control and Prevention that one in 88 American children have an autism spectrum disorder has stoked a debate about why the condition’s prevalence continues to rise. The C.D.C. said it was possible that the increase could be entirely attributed to better detection by teachers and doctors, while holding out the possibility of unknown environmental factors.
But the report, released last month, also appears to be serving as a lightning rod for those who question the legitimacy of a diagnosis whose estimated prevalence has nearly doubled since 2007.
As one person commenting on The New York Times’s online article about it put it, parents “want an ‘out’ for why little Johnny is a little hard to control.” Or, as another skeptic posted on a different Web site, “Just like how all of a sudden everyone had A.D.H.D. in the ’90s, now everyone has autism.”
According to the C.D.C., what critics condemn as over-diagnosis is most likely the opposite. Twenty percent of the 8-year-olds the agency’s reviewers identified as having the traits of autism by reviewing their school and medical records had not received an actual diagnosis. The sharpest increases appeared among Hispanic and black children, who historically have been less likely to receive an autism diagnosis. In South Korea, a recent study found a prevalence rate of one in 38 children, and a study in England found autism at roughly the same rate — 1 percent — in adults as in children, implying that the condition had gone unidentified previously, rather than an actual increase in its incidence.