Studies Suggest Higher Autism Rates
MICHELE NORRIS, Host:
For years, researchers have been trying to understand autism: what triggers the disorder, why are some children more affected than others, and is there a real increase in the prevalence of the disease or just an increased awareness of the problem? Two new government studies seek to shed some light on that last question.
The studies found that as many as one in 100 children have autism spectrum disorder. That would be a 50 percent increase in just over two years, and a much higher number than the current widely accepted estimate of one in 150 children.
These findings raise lots of questions. And for answers, we turn to Dr. Susan E. Levy. She's the director of the Regional Autism Center at Children's Hospital of Philadelphia, and she joins us now. Dr. Levy, welcome to the program.
SUSAN E: Thank you.
NORRIS: Now, were you surprised by these numbers?
LEVY: No, I'm not surprised. I think that there are a number of factors that account for the increased reports of prevalence. One factor is that we're getting much better at identifying children earlier, so they are adding to the count. Also, over time, the criteria have gotten much broader. So, in that way, we are accounting for a larger number of children.
NORRIS: So, there's still this baseline question: Do we know whether autism is actually more common than it used to be or just recognized more frequently?
LEVY: We don't exactly know, but I think we're starting to know a little bit better. There was a very interesting study that was published in Great Britain where they did a census, or they did a count of adults with autism spectrum disorder. So that at least would give us a few different periods or points of time so that we could say, is it increasing or not? And the count in Great Britain was very similar. So, it leads me to believe that it's not increasing as sharply. We're just getting better at identifying.
NORRIS: One of these studies - these two studies has not yet been published. The other was published in the current issue of Pediatrics. And it's based on a national phone survey where parents reported incidents of autism among their own children.
NORRIS: Are there limitations in a study that relies on parents to say whether or not a child is on the autism spectrum?
LEVY: Yes. While it's a wonderful tool, because there's no way we can go door-to-door to every family and test their children, it's one means of trying to get an estimate of how many children are affected with an autism spectrum disorder.
On the other hand, there are difficulties that you would encounter and including, there's no confirmation, there's no external validation that a child has an autism spectrum disorder. But it's a good strategy to try to get a handle and try to confirm from a different vantage point what the prevalence is.
NORRIS: It seems like there could be a lot of confusion surrounding autism spectrum disorders because you could be talking about Asperger's, you could be talking about, you know, what some would call a capital A autism. You could be talking about pervasive developmental disorder.
LEVY: Yes, there is a lot of confusion. And in reality, as the individual gets older, someone who has autism - capital A autism, as you mentioned - who has been lucky enough to have a spurt in language and development of certain skills and progresses, when they're an adolescent or an adult, they may be indistinguishable from someone who has Asperger's syndrome.
The categories are, in a sense, artificially designated by lists of different behavioral developmental characteristics. It's not like we have a biological measure that can say, oh, you have autism, capital A, and you have PDD-NOS because you have this substance in your blood or on your skin that helps us know for sure what category it is. It's all by observation and comparing to standards of the behavioral evaluation.
NORRIS: Dr. Levy, thank you very much for your time.
LEVY: My pleasure.
NORRIS: Dr. Susan Levy is a developmental pediatrician and she's the medical director of the Regional Autism Center at Children's Hospital of Philadelphia.
NPR transcripts are created on a rush deadline by Verb8tm, Inc., an NPR contractor, and produced using a proprietary transcription process developed with NPR. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.