Alternative explanations
Commenting on the research, Rebecca Gilbert, MD, PhD, chief scientific officer, American Parkinson Disease Association, said, “It has been established in prior research that there is an association between epilepsy and Parkinson’s disease.” The current study “shows that having had a prescription written for one of four antiepileptic medications was associated with subsequently receiving a diagnosis of Parkinson’s disease.”
Although one possible conclusion is that the AEDs themselves increase the risk of developing Parkinson’s disease, “there seem to be other alternative explanations as to why a person who had been prescribed AEDs has an increased risk of receiving a diagnosis of Parkinson’s disease,” said Dr. Gilbert, an associate professor of neurology at Bellevue Hospital Center, New York, who was not involved with the current study.
For example, pre-motor changes in the brain of persons with Parkinson’s disease “may increase the risk of requiring an AED by potentially increasing the risk of having a seizure,” and “changes in the brain caused by the seizures for which AEDs are prescribed may increase the risk of Parkinson’s disease.”
Moreover, psychiatric changes related to Parkinson’s disease may have led to the prescription for AEDs, because at least two of the AEDs are also prescribed for mood stabilization, Dr. Gilbert suggested.
“An unanswered question that the paper acknowledges is, what about people who receive AEDs for reasons other than seizures? Do they also have an increased risk of Parkinson’s disease? This would be an interesting population to focus on because it would remove the link between AEDs and seizure and focus on the association between AEDs and Parkinson’s disease,” Dr. Gilbert said.
She emphasized that people who take AEDs for seizures “should not jump to the conclusion that they must come off these medications so as not to increase their risk of developing Parkinson’s disease.” She noted that having seizures “can be dangerous – injuries can occur during a seizure, and if a seizure can’t be stopped or a number occur in rapid succession, brain injury may result.”
For these reasons, people with “a tendency to have seizures need to protect themselves with AEDs” and “should certainly reach out to their neurologists with any questions,” Dr. Gilbert said.
The Preventive Neurology Unit is funded by Barts Charity. The Apocrita High Performance Cluster facility, supported by Queen Mary University London Research–IT Services, was used for this research. Dr. Noyce has received grants from Barts Charity, Parkinson’s UK, Cure Parkinson’s, the Michael J. Fox Foundation, Innovate UK, Solvemed, and Alchemab and personal fees from AstraZeneca, AbbVie, Zambon, BIAL, uMedeor, Alchemab, Britannia, and Charco Neurotech outside the submitted work. The other authors’ disclosures are listed on the original article. Dr. Gilbert reports no relevant financial relationships.
A version of this article first appeared on Medscape.com.
