Dementia afflicts an estimated 55 million people worldwide. For a baby born in Europe today, their lifetime risk of developing Alzheimer’s disease or a related dementia is a staggering 1 in 3. But has dementia always been such a scourge?

Caleb Finch and Stanley Burstein of the University of Southern California suggest that it hasn’t.  

Ancient Roman writers describe cases that seem closer to our picture of dementia — though they seem to be rare. 

In the 2nd century AD, the Greek doctor Galen mentioned cases of elderly people with clear memory problems. But for Galen, mental decline, when it happened, typically began after the age of 80.  

Finch and Burstein argue that all of this suggests that our modern lifestyle is the main reason for the current dementia crisis. The researchers argue that there are lessons to learn from this — but firm conclusions are difficult to draw.

The study, a review of texts from Ancient Greece and Rome, was published in the Journal of Alzheimer’s Disease.