Autism’s Rising Numbers: Q&A with Autism Speaks Chief Science Officer

Date: 
March 27, 2014
Autism Speaks Chief Science Officer Rob Ring responds to questions sparked by the CDC’s updated estimate of autism prevalence

 Autism Speaks Chief Science Officer Rob Ring responds to questions about the CDC’s updated estimate of autism prevalence in the United States

What do these rising numbers - now 1 in 68 - tell us?
Behind all these numbers are real people – millions of children and adults affected by autism. These numbers also represent a huge and growing unmet need for services. This includes the need for medical, education, social and employment services and supports. As the number of people affected by autism rises, so does the economic cost of not addressing their need to become valued and valuable members of their communities. How high must the numbers go before we have a comprehensive national strategy to address this major public-health issue?

Are these numbers real?
Yes. We are getting closer to uncovering the true prevalence of autism spectrum disorder (ASD) in the United States. However, the indirect method the CDC uses to detect ASD is no doubt missing some, perhaps many cases. This is because it counts cases by reviewing records of autism-related services. So it only captures children who are already in the system and receiving services. It misses all those who have autism but remain undiagnosed or who otherwise cannot access services.

By contrast, we see much higher estimates of autism’s prevalence when investigators go into schools and communities to directly assess children for autism. The best direct-assessment numbers we have come from South Korea, where Autism Speaks funded a study that directly screened an entire community of school children. This study produced an estimated autism prevalence of 1 in 38. Two-thirds of these children had been previously undiagnosed and, so, would have been missed by the CDC’s records-based counting methods.

Autism Speaks is currently funding a similar direct-screening study in South Carolina, within one of the CDC’s Autism and Developmental Disabilities Monitoring (ADDM) sites. This will increase our understanding of autism’s true prevalence and the accuracy of the CDC’s indirect estimates. Importantly, it will also help identify barriers to diagnosis and better characterize the needs of children across the entire spectrum.

We should also note that the CDC's newest numbers - based on 2010 records - reflects autism diagnoses performed using the since-updated 4th edition of the Diagnostic and Statistical Manual of Mental Disorders. The 5th edition (DSM-5), published last May, contains substantially revised criteria for diagnosing ASD. It’s not yet clear how these changes will affect estimates of autism prevalence in the future. (For more on the DSM-5, click here.) 

Have we hit the peak?
We don’t know. But regardless of the numbers, we are looking at tremendous numbers of individuals needing services – services that are not keeping up with the need. We also know that autism tends to be under-recognized in many ethnic and economically disadvantaged communities across the U.S. This is also true of many rural communities distant from major medical centers and autism specialists. We need to better understand why we’re still missing so many individuals affected by autism and in need of services.

Can science explain why autism rates continue to rise?
Some but not all of the increase may be due to increased awareness and diagnosis. But much of the increase remains unexplained. Science has begun to identify some of the factors that increase or decrease the chances that a child will develop autism. For example, some studies suggest that increasing parental age is a contributor. But again, this doesn’t come close to explaining the dramatic increase.

At Autism Speaks, we’ve invested more than $200 million in research and scientific resources that can help us discover autism’s causes, prevention and treatment. But we need more funding – including funding from federal health agencies – to address this question.

What research is Autism Speaks prioritizing in response to the rising prevalence?
First and foremost, we know that the unmet need for services is growing at a terrible rate. We need more research dedicated to identifying and delivering the most-effective and accessible intervention programs in all our communities. We also need funding for research that improves our understanding and treatment of the medical conditions that frequently co-occur with autism. These include GI disorders, sleep disturbances and epilepsy, to name just a few.

The new prevalence numbers also underscore the reality that well over a half-million children with autism will reach adulthood in the United States over the next decade. The effects will reach beyond individual families to our entire society. We must develop and deliver the supports needed to help these individuals become valued and fulfilled members of their communities.

Other research priorities include identification of the risk factors that predispose to or protect against autism. It’s particularly frustrating for our community to know so little about why autism prevalence has increased so starkly over recent decades.

We also need research on autism prevalence among adults. Such research can help us understand how and why rates have changed over time. It can also help us better meet the needs of adults with autism.

Thank you for your questions. Please continue to send them to us at Science@AutismSpeaks.

For complete coverage of the CDC prevalence update with perspective from Autism Speaks science staff, click here.

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