Autism rates in schoolchildren jumped 15% between 2012 and 2014, continuing a two-decade rise, according to the latest data from the Centers for Disease Control and Prevention, which does not detail the reasons for the increase.
In a count of 11 communities across the United States, about one in 59 8-year-olds had autism in 2014, up from one in 68 in 2012. Overall, autism rates have climbed 150% since 2000, when the figure was one in 150 children.
The rise is partly driven by increasing diagnoses among African-American and Hispanic children, who are narrowing the diagnostic gap with their white classmates.
In the 2012 report, white children were diagnosed 50% more often than Hispanic children and 20% more than African-American children. In the latest report, that gap shrunk to 20% among Hispanics and 10% among blacks.
Autism is a developmental disorder characterized by a range of communication and social challenges, as well as repetitive behaviors like rocking, hand-flapping or obsessions.
The report is published every two years by the Autism and Developmental Disabilities Monitoring Network, a CDC-funded tracking system that assesses more than 300,000 8-year-old children for the disorder.
Craig Newschaffer, director of the AJ Drexel Autism Institute at Drexel University in Philadelphia, said he understands why people find it frustrating to see the autism rates continually climbing with no explanation. But, as genetic studies are increasingly revealing, autism is extremely complex, he said.
There are no obvious environmental causes for the rising rates, and without data on adults, it remains unclear whether more people have autism, or the condition has always been this common, just unrecognized or called by other names, he said.
The Autistic Self Advocacy Network, a nonprofit run by and for individuals on the spectrum, has long called for a study to examine rates in adults.