People using antiepileptic drugs are at a greater risk of Alzheimer's disease and dementia, finds a study.

Researchers at the University of Eastern Finland and the German Center for Neurodegenerative Diseases, DZNE, stated that continuous use of antiepileptic drugs for a period exceeding one year was associated with a 15 percent increased risk of Alzheimer's disease in the Finnish dataset, and with a 30 percent increased risk of dementia in the German dataset.

Some antiepileptic drugs are known to impair cognitive function, which refers to all different aspects of information processing. When the researchers compared different antiepileptic drugs, they found that the risk of Alzheimer's disease and dementia was specifically associated with drugs that impair cognitive function. These drugs were associated with a 20 percent increased risk of Alzheimer's disease and with a 60 percent increased risk of dementia.

The researchers also found that the higher the dose of a drug that impairs cognitive function, the higher the risk of dementia. However, other antiepileptic drugs, i.e. those which do not impair cognitive processing, were not associated with the risk. "More research should be conducted into the long-term cognitive effects of these drugs, especially among older people," Senior Researcher Heidi Taipale from the University of Eastern Finland said.

The association of antiepileptic drug use with Alzheimer's disease was assessed in Finnish persons diagnosed with Alzheimer's disease and their controls without the disease. This study is part of the nationwide register-based MEDALZ study, which includes all 70,718 persons diagnosed with Alzheimer's disease in Finland during 2005-2011 and their 282,862 controls. The association of antiepileptic drug use with dementia was investigated in a sample from a large German statutory health insurance provider, Allgemeine Ortskrankenkasse (AOK). The dataset includes 20,325 persons diagnosed with dementia in 2004-2011, and their 81,300 controls. The study has been published in the Journal of the American Geriatrics Society.