A large study from Karolinska Institutet in Sweden has found that people with autism may be more likely to develop Parkinson’s disease earlier in life. The findings suggest that autism and Parkinson’s disease could be linked through shared biological processes in the brain.
The study used data from more than two million people born in Sweden between 1974 and 1999. These individuals were followed from the age of 20 until the end of 2022. Researchers wanted to find out if there is a connection between autism spectrum disorder (ASD) and early-onset Parkinson’s disease, which is a condition that affects movement and muscle control.
The study found that people with an autism diagnosis were four times more likely to be diagnosed with Parkinson’s disease than people without autism.
This strong link remained even after accounting for factors like family background, mental health history, and socioeconomic status. In other words, the increased risk could not be explained by things like income level or inherited risk for mental illness or Parkinson’s.
The researchers believe that this link might be due to changes in how the brain’s dopamine system works. Dopamine is a chemical in the brain that helps control movement and also plays a role in social behavior.
In Parkinson’s disease, the brain loses cells that produce dopamine, leading to symptoms like shaking, slow movement, and stiffness. Some previous studies have suggested that dopamine might also be involved in autism, but more research is needed to understand how.
Dr. Weiyao Yin, the study’s lead author, says this research supports the idea that both autism and Parkinson’s disease could be affected by the same brain systems. While the link between the two conditions is not fully understood, the findings may help guide future research into what causes them and how they might be prevented or treated.
The study also looked at the role of other factors that might affect the results. For example, many people with autism also have depression or take medications like antidepressants and antipsychotics. Some of these drugs can cause side effects that look like Parkinson’s disease symptoms.
When researchers adjusted for these medications and mental health conditions, the risk of Parkinson’s disease among people with autism was lower—but still about twice as high as in those without autism.
It’s important to note that this study only looked at Parkinson’s cases that occurred before age 50. Early-onset Parkinson’s is rare, and most of the people in the study were still quite young—on average, about 34 years old. Because of this, the total number of Parkinson’s cases was small, and future studies will be needed to see if the increased risk continues into older age.
Dr. Sven Sandin, another author of the study, emphasized that while the link is worth noting, Parkinson’s disease before age 50 remains rare—even for people with autism. Still, the study highlights the importance of regular medical checkups for people with autism, as they often face other health challenges and are more likely to take medications that affect the brain.
In conclusion, the study shows a clear connection between autism and a higher risk of early-onset Parkinson’s disease. While the exact cause is not yet known, the results suggest that the two conditions may share common changes in the brain’s chemistry, especially involving dopamine.
These findings may help improve our understanding of both disorders and guide healthcare providers in monitoring and supporting people with autism as they age.
If you care about Parkinson’s disease, please read studies that Vitamin B may slow down cognitive decline, and Mediterranean diet could help lower risk of Parkinson’s.
For more health information, please see recent studies about how wheat gluten might be influencing our brain health, and Olive oil: a daily dose for better brain health..
The study is published in JAMA Neurology.
Copyright © 2025 Knowridge Science Report. All rights reserved.
