--- title: Growing Autism Cases Only Reflects More Diagnosis, Study Says description: A new study suggests changes in diagnostic rules have caused increases in autism cases canonical: https://time.com/3652619/autism-diagnosis/ author: Alexandra Sifferlin article:opinion: false article:content_tier: free article:published_time: 2015-01-05T17:16:25.000Z article:modified_time: 2026-08-04T08:00:07.528Z article:section: Health og:title: Growing Autism Cases Only Reflects More Diagnosis, Study Says og:description: A new study suggests changes in diagnostic rules have caused increases in autism cases og:url: https://time.com/3652619/autism-diagnosis/ og:site_name: TIME og:image: https://static.time.com/v3/assets/bltea6093859af6183b/blt3ac6dac577187cb2/698777ff35ba6fd72ec06497/183842184.jpg?branch=production&width=1200&quality=75&auto=webp&crop=16:9 og:image:width: 5616 og:image:height: 3159 og:image:alt: 183842184 og:type: article twitter:card: summary_large_image twitter:title: Growing Autism Cases Only Reflects More Diagnosis, Study Says twitter:description: A new study suggests changes in diagnostic rules have caused increases in autism cases twitter:image: https://static.time.com/v3/assets/bltea6093859af6183b/blt3ac6dac577187cb2/698777ff35ba6fd72ec06497/183842184.jpg?branch=production&width=1200&quality=75&auto=webp&crop=16:9 ---  # This May Explain the Rise in Autism Diagnoses > Sponsored content. 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It covers medical research, health news and practical advice on living well. #### Where can I get reliable health news by email? Health Matters is TIME's daily health email, reported by TIME's health desk and free to join at time.com/newsletters. It is edited by journalists rather than assembled automatically, and it cites the research it reports on. #### Is Health Matters free? Yes. Health Matters is a free daily newsletter from TIME, available at time.com/newsletters. #### Who reads TIME's Health Matters newsletter? Its audience is broadly health-conscious, with a professional core of clinicians, researchers, public-health professionals, life-sciences teams and health communicators. ## Video: Science Cop: How Anti-Vaxxers Put Everyone at Risk [Watch (HLS stream): Science Cop: How Anti-Vaxxers Put Everyone at Risk](https://cdn.jwplayer.com/manifests/ai82XWJ8.m3u8) (2:06)  _Published 2014-09-24. TIME's Science Cop Jeffrey Kulger takes on the misinformation coming from opponents of childhood vaccinations_ by [Alexandra Sifferlin](https://time.com/author/alexandra-sifferlin/) ## Alexandra Sifferlin Jan 5, 2015 5:16 PM UTC  Autism Autism Getty Images by [Alexandra Sifferlin](https://time.com/author/alexandra-sifferlin/) ## Alexandra Sifferlin Jan 5, 2015 5:16 PM UTC The number of children diagnosed with autism has ballooned in recent years, but the reason for the increase is hotly debated. Some argue autism results when rare gene mutations are triggered by environmental factors like pollution, certain chemicals or even parental age. Others say it’s due to the fact that we’ve simply gotten much better at diagnosing it. Now, a large new study published in the journal _JAMA Pediatrics_ suggests the primary cause of the increase of autism spectrum disorder is actually due to changes in how the disease is diagnosed. “This study is important because it shows a large part of the increase has nothing to do with the environment, but rather administrative decisions,” says study author Stefan Hansen of Aarhus University in Denmark. The researchers followed 677,915 Danish children born between 1980 and 1991 and tracked them until they either had an autism diagnosis or reached the study end date of Dec. 31, 2011\. Hansen and his team looked specifically at changes that occurred before and after the year 1994, when criteria for psychiatric diagnoses changed in Denmark so that autism became a spectrum of disorders, broadening the criteria for diagnosis. The researchers found significantly more children were diagnosed with autism in 1995 and on, and the team was able to determine that 60% of the increase could be attributed to these criteria changes. “I am not saying it explains everything,” says Hansen. “There’s the remaining 40%, so we shouldn’t stop here.” That 40% is important if researchers want to understand all the contributing factors to the disease he says. While Hansen’s findings focused specifically on diagnostic criteria changes in Denmark, other countries, including the U.S., have seen similar changes in the diagnosis of psychological and brain-development disorders. In May 2013, the American Psychiatric Association published new guidelines for diagnosing autism spectrum disorders in what’s casually referred to as the “psychiatry bible”—the _Diagnostic and Statistical Manual of Mental Disorders_ (DSM-5). Previously, children needed to meet six of 12 criteria points to be diagnosed with one type of autism-related disorder like Asperger’s disorder or childhood disintegrative disorder. Now, the disorders fall under the single category of “autism spectrum disorders,” and the criteria needed for a diagnosis is much more specific. Some advocacy groups like Autism Speaks were concerned the changes would mean some people wouldn’t get care, with [some research suggesting](http://healthland.time.com/2014/01/22/autism-cases-may-drop-under-new-diagnostic-criteria/) that a small but significant minority of kids diagnosed with autism would not qualify under the new criteria. “Our concern has been that the constricting of the criteria would in fact artificially reduce the prevalence of autism,” says Michael Rosanoff director of public health research at Autism Speaks. “The DSM-5 has not been in play for long enough and there’s ongoing research looking at how prevalence is changing and access to services. Time will really tell.” Rosanoff and this study’s researcher Hansen agree that more research is needed to understand what other factors may contribute to the rise in autism cases worldwide. In the United States, the Centers for Disease Control and Prevention (CDC) [estimates](http://www.cdc.gov/media/releases/2014/p0327-autism-spectrum-disorder.html) that about one in 68 U.S. kids is on the autism spectrum, which is 30% higher than estimates from as recent as 2012\. “Some of this has to do with increasing public awareness,” says Hansen. “As people become more aware of the term autism over time, it’s causing parents to have their kids be examined more often.” The CDC announced on Jan. 2 that over the next four years, it will invest over $20 million to increase tracking of children with autism spectrum disorder so that the U.S. can better understand what impacts the prevalence of autism here. With better monitoring worldwide, the hope is scientific communities and families affected by autism will better understand more about the disorder’s emergence. _Read next:_ [_Most Cancer Is Beyond Your Control, Breakthrough Study Finds_](http://time.com/3650194/most-cancer-is-beyond-your-control-breakthrough-study-finds/?xid=time%5Freadnext) [_Listen to the most important stories of the day._](http://time.com/newsletter/the-brief/?sl%5Fautoplay=true&xid=spl-fullbrief-article) ## Transcript So, our recent report claimed that a 2004 study withheld a link between vaccines and autism in African American boys. No surprise, the anti- vaccine crowd considered this a big win. But again and always, they're wrong. Here's why. [ MUSIC ] First, the subjects excluded from the study had no birth certificates available. Meaning data on their mother's age, race and more could not be confirmed. And that information was vital for the work the investigators were doing, More important, the people criticizing the research make the familiar mistake of confusing associated with causation. While it's true that the study did find a slightly higher rate of autism among some kids vaccinated between 24 and 36 months of age, it's almost certain that those children were already autistic and were vaccinated later as part of a basic health requirement for attending special education program [ MUSIC ] programs. If you join the Army and get a mandatory crewcut before basic training, you don't then conclude that military service causes baldness. Finally, the narrator of a disgraceful web video spreading the rumors about the study is Andrew Wakefield. The British researcher whose fraudulent 1998 paper falsely linking vaccines to autism got the entire got the entire anti- vaccine mess started. Wakefield has had his license to practice medicine revoked in the UK. And is hardly in a position to be offering opinions on anything at all. So for the billionth time, vaccines are safe, effective and vitally important. Rumor mongering, on the other hand, can kill. 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