Autism is becoming increasingly common in young adults

Four times as many children have been diagnosed with autism in the past two decades, thanks to improved awareness, better screening and evolving definitions. A new study suggests that diagnoses among younger adults have increased more rapidly over the past decade.

Autism spectrum disorder rose 175% among US residents, from 2.3 per 1,000 in 2011 to 6.3 per 1,000 in 2022, researchers found. The number of diagnoses rose faster during that period among adults in their mid-20s to mid-30s, according to a study published Wednesday in JAMA Network Open.

Researchers involved in the study wanted to assess how many adults had been diagnosed with autism, since previous studies largely focused on school-age children, said Luke Grosvenor, the study’s lead author and a postdoctoral researcher at Kaiser Permanente’s research department in North America. California.

“There is a dearth of research focused on autistic adults,” Grosvenor said.

Children between the ages of 5 and 8 had the highest rate of autism with 30.3 diagnoses per 1,000 children in 2022. The second highest rate was children aged 4 and under at 28.8 per 1,000 children.

Study tracks growing autism rates in adults

The study found that the prevalence of autism is much lower among younger adults than among children, but also that autism is increasing more rapidly among these adults. The rate of autism among adults aged 26 to 34 increased by more than 450% between 2011 and 2022, the study found.

The growing autism rates among these adults show that “we need to improve transition services for autistic individuals and their families” as they enter adulthood, Grosvenor said.

Although children can access services such as speech and other therapy at school, they often lose access to such care as they grow into adulthood. But the need isn’t going away, Grosvenor said.

“That’s the services cliff in autism,” says Grosvenor, adding that it is “critically important” that adults with autism get the care they need.

Experts not involved in the study said the study provides valuable insight into the prevalence of autism in adults, a group that federal researchers do not routinely monitor in autism surveillance.

Dr. Alycia Halladay, chief science officer for the Autism Science Foundation, said the numbers in the study showed similar results to what the Centers for Disease Control and Prevention has reported for young children. But she said the study’s estimates for adults are “hugely important” and draw attention to the need to track autism patients over time. She said the research also shows the value of gathering information from medical records to provide a more detailed picture of people with autism.

However, the study does not provide more detailed insight into how older adults with autism fare, Halladay said. She said she would like to see a survey of adults with autism that would address questions such as educational attainment and employment prospects.

Autism rates vary by race and gender

The JAMA Network Study also reported differences in autism rates by race, ethnicity and gender. Diagnosis rates were highest among American Indian or Alaska Native children and adults. The increase in autism was greater among black, Asian, Hispanic, and American Indian and Alaska Native children compared to white children.

Boys were still more likely to be diagnosed with autism than girls. However, the report noted that autism diagnoses among girls increased faster than among boys during the study period.

Halladay said biological factors contribute to higher autism rates among boys.

“Boys’ and girls’ brains are just different, and they develop at different rates,” says Halladay. “Girls are more likely to have better social skills, which is why it is thought that they may be able to mask the characteristics of autism better than boys.”