In People With Autism, ADHD Rates Still Common in Adulthood

Too often, ADHD and autism coincide in children. New research finds that for many of those kids, this dual diagnosis continues into adult life.

Having attention deficit hyperactivity disorder (ADHD) alongside an autism diagnosis was also linked to worse health outcomes overall for adults, the study found.

“Generally speaking, rates of ADHD decrease as children grow up, but we found that ADHD rates among autistic adults were nearly identical to ADHD rates seen in autistic children,” said study lead author Benjamin Yerys. He’s a psychologist at the Children’s Hospital of Philadelphia.

“As rates of autism continue to rise in childhood, at a clinical level, we need to make sure that an increased number of patients with co-occurring ADHD in adulthood have access to support programs that provide autism as well as ADHD services across the lifespan of these patients,” said Yerys, who also directs the PASSAGE program at the hospital’s Center for Autism Research.

His team published its findings Feb. 12 in JAMA Network Open.

Autism and ADHD often are diagnosed together in childhood. But how many of these kids will shed their ADHD diagnosis as they age?

To find out, Yerys and colleagues pored through 2008-2019 Medicaid data on more than 3.5 million U.S. adults.

About 27% of adults who had autism but no intellectual disabilities also had a diagnosis of ADHD.

That’s 10 times the rate seen among the general population of Medicaid enrollees, the study authors noted.

ADHD diagnoses rose to 40% among people with autism who also had some form of intellectual disability.

ADHD can be controlled by certain medications. However, the study found that fewer than 50% of the adults affected received any form of ADHD medication.

Having ADHD appeared to affect more than just mental health, the Philadelphia team noted.

Adults with ADHD had rates of substance use, heart conditions and injury that were markedly higher than people without the condition, the research showed.

However, when people with ADHD took medications to curb the disorder, in most cases increases in poor physical health largely disappeared, according to Yerys’ team.

More information

Find out more about ADHD at the American Academy of Pediatrics.

SOURCE: Children’s Hospital of Philadelphia, news release, Feb. 12, 2025