Autism diagnosis rates have tripled in the last decade, new study finds

Rates of autism diagnoses have risen substantially across the US in recent years, nearly tripling between 2011 and 2022.

The number of people diagnosed with the developmental disability climbed by 175 percent over the decade, according to a new analysis released Wednesday.

“The improvement and expansion of universal developmental screening likely accounts for some of the increase in diagnosis rates we found in this study,” Kaiser Permanente’s Luke Grosvenor, who led the research, said in a statement. “The magnitude of the rate increases and variability by age, gender, race, and ethnicity suggests factors other than improved screening are also contributing to the rate increases.”

Autism disorder, which is caused by differences in the brain, has been reported to be nearly four times more common among boys than in girls. Around 1 in 36 children has been diagnosed with autism, according to recent federal data.

To reach these conclusions, Grosvenor, physicians at Kaiser Permanente and other health research facilities across the country, used data from more than 12 million patients enrolled in major healthcare systems. Their study was published in the journal JAMA Network Open.

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They found that the autism diagnosis rate was highest among children between the ages of five and eight years old, rising from 2.3 per 1,000 people in 2011 to 6.3 in 2022.

Whereas, the largest increase in diagnoses was reported among young adults, women and girls. New diagnoses for girls soared by 305 percent, while diagnoses for boys rose by 185 percent.

“We’re seeing a narrowing in the gap between males and females who are diagnosed with autism,” said co-author Lisa Croen. “This is very interesting, but we don’t know why. That’s a direction for future research to explore.”

In adult women, there was a 315 percent hike in diagnoses, compared to a 215 percent rise in men, which may be due to increased awareness of autism in women related to improved tools or expanded representation on social media.

The rise was especially notable in adults ages 26 to 34, with a 450 percent increase in diagnoses.

“Rates reported here may underestimate the true prevalence of [diagnosis] in adults, especially older female adults, as many would not have been screened in childhood and remain undiagnosed,” the authors wrote. “Nevertheless, our findings indicate that the population of autistic adults in the US will continue to grow, underscoring a need for expanded health care services.”

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There were also differences reported by race, with diagnosis rates the highest among Indigenous children and adults. This may be because of the proximity between Native communities and specific mental health resource network locations. Although a higher prevalence of mental and physical disabilities has been reported among American Indian or Alaska Natives.

Increases were greater among Black, Asian, American Indian or Alaska Native, and Hispanic children compared with white children.

The study noted there were no increases in diagnoses in 2020, likely due to healthcare disruptions caused by the Covid-19 pandemic. Rates rebounded after 2020 and were higher in 2021 and 2022 than prior years.

“Further research is warranted as to whether this reflects increased access to diagnostic services versus any true increase in diagnosis prevalence,” the report said.