Autism Diagnosis Linked to Higher Risk of Early Parkinson’s Disease

A large-scale study from Karolinska Institutet has found that individuals diagnosed with autism spectrum disorder (ASD) face a significantly higher risk of developing Parkinson’s disease before the age of 50.

The research, published in JAMA Neurology, suggests that the two conditions may share biological mechanisms related to brain function.

Study design and population

The investigation used registry data covering over two million people born in Sweden between 1974 and 1999. Participants were followed from age 20 through the end of 2022 to explore the relationship between ASD, a neuropsychiatric condition affecting behavior, communication and cognition, and early-onset Parkinson’s disease, a neurodegenerative disorder characterized by impaired movement.

Elevated risk remains after adjustments

Results showed that people with an autism diagnosis were approximately four times more likely to develop Parkinson’s disease than those without ASD. This association persisted after accounting for socioeconomic status, genetic predispositions to mental illness or Parkinson’s disease, and other confounding factors.

Researchers propose that disruptions to the dopamine system in the brain might underlie both conditions. Dopamine is a neurotransmitter important in regulating social behavior and motor control. While Parkinson’s disease is known for the degeneration of dopamine-producing neurons, dopamine’s role in autism requires further research.

Influence of medications and mental health

Depression and the use of antidepressant and antipsychotic medications are common among people with autism. Since antipsychotic drugs can produce Parkinson’s-like symptoms, the team adjusted for these factors, finding the risk of Parkinson’s disease in ASD patients was reduced but still twice as high compared to the general population.

The study focused exclusively on Parkinson’s disease cases diagnosed before 50 years of age. With the average participant age being 34 at the study’s conclusion, the incidence of Parkinson’s was low. Future research is needed to determine if this increased risk persists into older age.

Clinical implications

The authors emphasize the importance of long-term medical monitoring for people with ASD, a group already vulnerable due to high rates of comorbid conditions and psychotropic medication use. They also note that Parkinson’s disease remains rare before 50, even among those with autism.

The study was funded mainly by the Simons Foundation and the Swedish Research Council. Some authors disclosed financial ties to pharmaceutical companies unrelated to the study.

Reference: Yin W, Reichenberg A, Beeri MS, et al. Risk of Parkinson disease in individuals with autism spectrum disorder. JAMA Neurol. 2025. doi:10.1001/jamaneurol.2025.1284

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