In recent years, autism-spectrum disorders have garnered a lot of attention in the media and in popular culture. Autism, it seems today, is everywhere. It’s not uncommon to know a person with autism or a parent of a child who has autism. So you’d be forgiven if you thought that autism is more prevalent now than it was 20 years ago.
Except you’d be wrong, according to the findings of a new study.
Amanda Baxter, an epidemiologist at the Queensland Centre for Mental Health Research in Australia, and her colleagues pulled together data from 1990 to 2010 on autism spectrum disorders from around the globe. They found the prevalence of autism was 7.5 in 1,000 in 1990 and 7.6 in 1,000 in 2010—a small difference that wasn’t statistically significant. Moreover, they found no significant variation in autism rates between different regions of the world. (You can read the entire study at Psychological Medicine ( pdf ).)
So what accounts for the apparent, if not actual, increase? Julia Belluz interviewed Baxter for Vox:
“Reports of higher rates of autism in recent years means that we are doing a better job of identifying people on the autism disorder spectrum, particularly those at the milder end of the spectrum, and also identifying them at an earlier age.”
Despite the increased awareness, autism remains a murky disease. The exact cause has yet to be identified, though researchers have been zeroing in on certain inherited genes and de novo mutations, or mutations that occur in an egg or sperm. There’s also little known about the effects of the disorder as people reach adulthood, something that Baxter and her colleagues hope future research will shed more light on.
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