Autism May Be More Common Than Thought
Survey Shows 1 in 91 Children May Have Autism Spectrum Disorder
Interpreting the New Autism Data
Experts are not certain what to make of the findings but urged caution in interpreting them. "In ASD, we don't know if the change in the numbers over time is a change in the actual condition," Arias says, or to other factors.
Among the other factors are that awareness of the condition is more widespread, she says, and the condition is now thought about on a continuum, so what is now considered a mild case may not have been diagnosed in past years.
"We also know from other studies that there has been a decreasing average age of diagnosis, which would lead to increasing prevalence at any one point in time," Kogan says.
In recent years, experts have also realized that ASD often coexists with other disorders, such as attention deficit hyperactivity disorder, and a child who previously was only diagnosed with ADHD may now have a diagnosis of both ADHD and ASD, for instance.
And what of the 38% of children who seemed to have shed their diagnosis? "We know that some children diagnosed at young ages won't meet the criteria as they age," Kogan says. Some parents surveyed may have been reporting a health care provider telling them they suspected ASD, rather than the actual diagnosis, he says.
In addition, some research has suggested that some children do have resolution from the condition and lose the diagnosis with age.
Experts who reviewed the survey for WebMD say it is a carefully done report. They, too, are uncertain about what to make of the dramatic rise. "What it may be is that the numbers are the same but we are capturing a milder form [in the survey]," says Susan Hyman, MD, associate professor of pediatrics and division chief of neurodevelopmental and behavioral pediatrics at the University of Rochester and chairwoman of the American Academy of Pediatrics' autism subcommittee.
''The big take-home message is that autism spectrum disorders are more common than we thought 50 or 60 years ago," says Susan Levy, MD, a member of the autism subcommittee of the American Academy of Pediatrics and an autism expert at Children's Hospital of Philadelphia. The newer surveys, such as the one published in Pediatrics, suggest the disorders are more common, she says, than people thought even 10 years ago. Like all surveys, however, Levy says, it may not be completely accurate.
For parents, the message is clear, whether the increase in numbers turns out to be totally representative of the population or not, experts say. It's important to know potential signs of ASD and to consult a pediatrician as soon as possible to check out the child, experts stress. Among the potential signs are social interaction problems, language difficulties, or behavior problems such as repetitive behavior.