Study Links Autism and Intellectual Disability to Higher Parkinsonism Rates

Older Americans with autism, intellectual disability or both were diagnosed with Parkinson’s disease or related movement disorders at about two to three times the rate of other adults, according to a peer-reviewed analysis of Medicare and Medicaid claims. An outside neurologist cautions that the findings show a correlation, not a certainty.

The study, in the journal Autism, was dated Oct. 24, 2026 by HealthDay, and was summarized by HealthDay News on Oct. 28 and Fox News on Oct. 30. Greg Wallace of George Washington University’s Department of Speech, Language and Hearing Sciences is the lead author. The analysis covered nearly 57 million Americans aged 45 and older whose records spanned 2017 to 2019. It is observational: it counts diagnoses in insurance claims and does not examine patients. Neither news report names a funder, and the paper’s funding disclosure was not reviewed for this article.

The share of people with a parkinsonism diagnosis was about 1.57% among adults with neither condition, 3.83% among those with autism alone, 4.32% among those with intellectual disability alone, and 4.86% among those with both, as Fox News reported the figures. In absolute terms, that is a gap of roughly 2.3, 2.8 and 3.3 percentage points. In relative terms, by this paper’s arithmetic on those numbers, the rates are about 2.4, 2.8 and 3.1 times the comparison group’s.

HealthDay reported age-standardized rates per 100,000 person-years of 1,341 for people with both autism and intellectual disability, 1,017 for intellectual disability alone, 977 for autism alone and 234 for the comparison group. HealthDay reported that autistic adults still showed elevated risk after controlling for prescribed medications, and that clinicians should watch for drugs such as antipsychotics, which can cause Parkinson’s-related side effects.

Wallace said the cases “aren’t simply a byproduct of lifelong motor challenges,” and that it is important for clinicians to “establish clear baselines of motor skills,” according to HealthDay. Dr. Lee Murray, a neurologist who was not involved in the study, told Fox News that the finding “does not imply that someone with autism is certain to develop Parkinson’s.” He added that patients with autism can have atypical movements that are misdiagnosed as Parkinson’s.

That last point is the study’s main limit. Claims data record what doctors billed, not necessarily what patients have, and the people studied are those enrolled in Medicare or Medicaid, which may not represent all older adults. Even so, the authors’ practical suggestion is modest: for adults with these conditions, a documented baseline of movement would help doctors tell lifelong differences from new symptoms.

Most older adults with autism or intellectual disability, even on the study’s highest figure, did not have a parkinsonism diagnosis. About 95 in 100 people in the highest group had none.