Some anti-epileptic drugs (AEDs) may increase the risk of dementia and Alzheimer’s disease (AD), new research suggests.

Researchers matched 20,325 people with dementia of any type in Germany with 81,300 controls, and 70,718 AD patients from Finland with 282,858 controls. The average age was 76 years in Germany and 78 years in Finland.

Regular use was defined as at least four sequential quarters in Germany and at least a year’s continual use in Finland. The researchers allowed two years between the start of AED use and dementia diagnosis to reduce the risk of bias.

Regular use of AEDs with known cognitive side-effects increased the risk of dementia by 59 per cent and AD by 19 per cent. Occasional use of the same AEDs increased the risk of dementia by 20 per cent and AD by 16 per cent. However, regular and occasional use of AEDs without known cognitive side-effects did not seem to increase the risk.

“Our findings highlight the importance of possible long-term adverse cognitive effects of AEDs in older adults,” the authors write. “Large prospective clinical studies are needed to confirm whether the association between AED use and dementia risk is causal.”

^{J Am Geriatr Soc DOI: 10.1111/jgs.15358}