You probably know someone who lives with epilepsy, or you manage it yourself. Most people picture seizures as the main day-to-day challenge. New research now points to something quieter that may show up years later.
A study published October 14, 2026, in Neurology found that people with epilepsy were more likely to develop dementia before age 65 than people without the condition. Dementia that starts before 65 is known as young-onset dementia.
Researchers followed about 12,900 French adults aged 30 to 55 who were newly diagnosed with epilepsy in 2008. Over the next 10 years, 2.2 percent of them developed dementia, compared with 0.2 percent of around 129,000 adults without epilepsy.
That worked out to a roughly 6-fold higher risk for the newly diagnosed group. People who had been living with epilepsy for longer had a 74 percent higher risk than people without.
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The study is observational. It shows a statistically significant link, not that epilepsy directly causes dementia.
How the researchers reached the finding
The team used two approaches with national health databases. In France, 11,360 people with young-onset dementia were matched against 113,600 people without. The Swedish arm compared 16,433 people with dementia against 164,330 people without.
Among the French dementia group, 12.5 percent had an earlier epilepsy diagnosis. In the control group it was 1.2 percent.
The second approach was prospective. It followed people newly diagnosed with epilepsy forward in time, alongside those with existing epilepsy and people without the condition.
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What this may mean for people with epilepsy
Lead author Vincent Navarro, at Sorbonne University in Paris, said the findings support adding dementia prevention to epilepsy care. That could mean earlier checks of cognitive risks and tighter control of factors like high blood pressure.
According to the Centers for Disease Control and Prevention, about 2.9 million US adults and 456,000 children have active epilepsy. That is roughly 1 percent of all adults.
Factors like high blood pressure sit on the list of modifiable dementia risks researchers already highlight to help lower overall risk.
The research team noted limits. They did not have detailed information on the specific type of dementia or the type of epilepsy. France and Sweden both have universal healthcare, so the pattern may not translate directly to other systems.
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Navarro's team also stressed that the absolute risk remains low. Over 10 years, roughly 2 in 100 newly diagnosed patients developed dementia. The study was funded by the French National Research Agency.
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This article is made and published by Jesper Bengtson, who may have used AI in the preparation.