According to federal officials, the number of children in the school system who have been diagnosed with autistism has jumped to as high as 1 in 50. Only five years ago the number was closer to 1 in 88.
The author of the report – which came from the U.S. Center of Disease Control and Prevention – Stephen Blumberg said that he was surprised by the numbers. He added that based on the findings, the number of kids with disorders on the autism spectrum is much higher than has been estimated.
To provide context, he pointed out that if the numbers are accurate, there's on average 1 child with autism on every 50-person school bus in America.
Michael Rosanoff, associate director for Public Health Research and Scientific Review at Autism Speaks, said that "this study added to the evidence suggesting that we are underestimating the prevalence of autism in the United States."
This report, however, underestimated the real prevalence of autism, Rosanoff said. "It's probably much higher," he said.
These children are most likely having trouble with social skills, which limits their ability to interact with others in the classroom and in social situations, Rosanoff said.
Blumberg attributed the high numbers to better methods of diagnosis, also noting that boys were 4 times as likely to be diagnosed as girls of all ages. According to the report, the majority of the diagnoses noted in the report were first identified after the last report on autism prevalence was published by the CDC in 2008.
Neither survey bias nor a change in the environment explained the spike. Chiefly it appears that doctors have simply become more vigilant about looking for autism symptoms in their patients, especially the older ones.
"It would certainly make sense that those with unrecognized autism spectrum disorder may have symptoms that are milder than children who have been diagnosed earlier," he said.
"What we are seeing is that children who have not been diagnosed in the past are now being diagnosed," he said. "That is likely due to doctors and other health care providers being better at recognizing the more milder symptoms of autism and being able to diagnose those."
To reach their conclusions, researchers gathered data from the National Survey of Children's Health, which is a national telephone survey of nearly 96,000 American households. As part of the survey, parents are asked whether they have a child diagnosed with autism.