A recent study indicates that older adults with autism face a significantly higher risk of developing symptoms associated with Parkinson’s disease compared to the general population. Researchers examined the health records of nearly 57 million individuals aged 45 and older and found that approximately 4 percent of autistic adults exhibited signs of Parkinsonism—the movement difficulties linked to Parkinson’s disease—compared with fewer than 1.6 percent among those without autism or intellectual disabilities.

The study also identified elevated rates of Parkinsonism among people with intellectual disabilities, at 4.3 percent, with the highest prevalence—nearly 4.9 percent—occurring in individuals diagnosed with both autism and an intellectual disability. Additionally, autistic adults developed these motor symptoms at roughly four times the rate observed in non-autistic individuals, suggesting an increased vulnerability beyond typical coordination challenges associated with autism.

Conducted by researchers at George Washington University in the United States, the study addressed the potential influence of medications. While certain antipsychotic drugs frequently prescribed to autistic individuals have been known to cause Parkinson’s-like side effects, the research found that the heightened risk of Parkinsonism persisted even after accounting for drug exposure. This implies that the increased incidence is not solely due to medication effects.

Parkinson’s disease is characterized by the progressive loss of dopamine-producing nerve cells in the brain, leading to symptoms such as tremors, muscle stiffness, and slowed movement. Autism, a lifelong developmental condition, affects communication and social interaction and is estimated to impact approximately 1.2 million people in the United Kingdom. Since 1998, autism diagnoses in the UK have increased by nearly 800 percent, a change attributed mostly to improved awareness and diagnostic practices.

Lead author Professor Greg Wallace emphasized the clinical importance of the findings, stating that recognizing the heightened risk of Parkinsonism in autistic adults should prompt healthcare providers to establish and monitor motor function baselines over time. The study’s results were published in the journal Autism, calling for greater attention to motor health in the aging autistic population.