WEDNESDAY, Oct. 28, 2026 (HealthDay News) — Older people with autism are more likely to develop symptoms of Parkinson’s disease, a new study says.
About 3.8% of people 45 and older with autism wind up with tremors and movement problems linked to Parkinson’s disease, compared to under 1.6% of people without either autism or intellectual disability, researchers reported Oct. 24 in the journal Autism.
These findings are based on analysis of nearly 57 million Americans 45 and older who filed Medicare or Medicaid claims from 2017 to 2019.
“Utilizing the largest sources of healthcare for middle- and older-aged Americans, this study demonstrates an increased propensity for autistic adults to experience parkinsonism (i.e., the motor symptoms associated with Parkinson’s Disease), joining a growing body of research,” lead researcher Greg Wallace said in a news release. He is a professor of speech, language and hearing sciences at George Washington University.
The study also found increased rates of Parkinson’s symptoms among people with intellectual disabilities (4.3%) and those with both autism and intellectual disability (nearly 4.9%).
Overall, the age-standardized rates of Parkinson’s symptoms were:
1,341 cases per 100,000 person-years for people with both autism and intellectual disability
1,017 cases for people with intellectual disability alone
977 cases for people with autism alone
234 cases for the control group
Person-years reflect the amount of time a person was observed during a study while at risk for an outcome — in this case, symptoms related to Parkinson’s.
The results indicate that “these cases aren’t simply a byproduct of lifelong motor challenges” that occur among people with autism or intellectual disability, Wallace said.
“It is therefore important for clinicians to establish clear baselines of motor skills and challenges during adulthood that can be tracked over time,” Wallace said.
These results indicate that motor difficulties associated with autism might make people with the condition more prone to develop Parkinson’s symptoms, researchers concluded.
Even after controlling for prescribed medications, adults with autism still showed an elevated risk of Parkinson’s disease symptoms. However, doctors should also be on guard for medications that might cause side effects related to Parkinson’s that are prescribed for people with autism, such as antipsychotics, researchers wrote.
More research is needed to nail down the age at which Parkinson’s symptoms begin to emerge among autistic people, and the factors that might predict their development, researchers said.
More information
The University of Missouri has more on autism and Parkinson’s disease.
SOURCE: George Washington University, news release, Oct. 26, 2026
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