People with epilepsy may face a significantly higher risk of developing dementia before the age of 65, according to a large new study that analyzed the medical records of hundreds of thousands of people in France and Sweden.
Researchers found that epilepsy appeared repeatedly in people later diagnosed with early-onset dementia, a form of the disease that develops before age 65. The study, published in Neurologythe medical journal of the American Academy of Neurology, used two distinct research approaches in two countries and arrived at similar results.
Dr. Rebecca Spiegel, neurologist and chief of EEG and Epilepsy at Stony Brook Medicine, spoke with News week on recent discoveries.
“They are important, but we have to be careful,” she said. “In some patients, the onset of new seizures may be an early manifestation of neurodegeneration rather than its cause and, in addition, people with epilepsy may experience cognitive difficulties that do not necessarily indicate dementia and may be treatable, particularly given the disproportionate incidence of depression and anxiety in this population.”
Link between epilepsy and early dementia
The researchers stressed that the results do not show that epilepsy directly causes early dementia. Instead, the study identified a strong association between the two conditions. They also noted that although the relative increase in risk was substantial, the overall likelihood of developing early-onset dementia remained low.
Early-onset dementia is less common than dementia diagnosed later in life, but it can have a particularly profound and devastating impact because it affects people during their working years and often while they are caring for their families.
To study possible links to epilepsy, researchers used national health databases in France and Sweden.
Part of the study looked back in time to determine whether people diagnosed with early-onset dementia had ever received a diagnosis of epilepsy or medication for epilepsy. A second analysis followed people with epilepsy over time to see if they later developed dementia.
In the retrospective analysis, researchers compared 11,360 people with young-onset dementia in France with 113,600 people of the same age and gender who did not have dementia. In Sweden, they compared 16,433 people with early-onset dementia to 164,330 people without the condition.
The differences between the groups were striking.
In France, 12.5 percent of people with early-onset dementia had already been diagnosed with epilepsy, compared to just 1.2 percent of people without dementia. The researchers also found that 27.3 percent of people with dementia had received epilepsy medication, compared to 10.3 percent of those without dementia.
Swedish data showed similar trends, reinforcing the consistency of findings across two distinct national health systems.
Track people over time
The second part of the research followed French adults aged 30 to 55 who were newly diagnosed with epilepsy in 2008 and followed them for 10 years.
During the follow-up period, 2.2 percent of newly diagnosed patients developed early-onset dementia. This compares to 1.7 percent of people who already had epilepsy before 2008 and 0.2 percent of people without epilepsy.
After accounting for other factors that may affect dementia risk, including stroke, mood disorders, and head trauma, researchers found that people newly diagnosed with epilepsy were six times more likely to develop early-onset dementia than people without epilepsy. People with epilepsy were 74 percent more likely to develop dementia than people without the condition.
Still, the study authors cautioned that several limitations remain. The databases did not contain detailed information on specific types or causes of dementia, or the different forms of epilepsy experienced by participants.
The researchers also noted that the study relied on health data from France and Sweden, two high-income countries with universal health systems. As a result, results may not apply equally to populations in other countries or healthcare settings.
Although the study adds to the growing evidence of a link between epilepsy and cognitive decline, more research is needed to determine why this link exists and whether reducing the risks of epilepsy could help reduce the risk of early dementia.
“The reassuring message is that, despite the increased relative risk, the vast majority of epilepsy patients in this study did not develop early-onset dementia,” Spiegel said. “Nevertheless, the results should encourage greater attention to cognitive assessment in people with epilepsy.”
News week contacted the study’s press contact at the American Academy of Neurology, whose Neurology is a medical journal, for more information.
Reference
Calonge, Q., et al. (2026). Association between epilepsy and early dementia. Neurology. https://doi.org/10.1212/WNL.0000000000218700.
Contact Newsweek editors about this story: Kara Dolman And Paul Donnelley.
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