Research: depression and dementia are linked

Could the “wear and tear” of depression make the brain more vulnerable?

Scientists have long suspected that depression and dementia are linked – and two new studies published in the journal “Neurology” support this theory.

For the first study, researchers followed more than 900 elderly people for 17 years and found that those who had signs of depression early on were more likely to experience dementia later in life.

The second study, involving over 1000 people, showed that having two or more episodes of depression nearly doubled the risk of dementia.

Researchers stress that these findings do not mean that depression causes dementia.

Dr. Steven Arnold directs the Penn Memory Center. He says several factors could explain the link.

Arnold: Certainly one of the leading hypotheses is that depression and psychological distress can have a chronic wear and tear effect on the brain, making the brain more vulnerable to some of the deterioration, or degeneration.

Depression could also cause reduced social interactions and and withdrawal from other activities that keep the brain healthy. Some experts suggest depression could be an early sign of dementia.

Dr. Adam Davey of Temple University’s department of Public health says no matter what the nature of the relationship – the finding is an added impetus to treat depression:

Davey: To this point, depression is the only treatable piece of the equation, and so identifying and treating depression would be an important piece of the puzzle.

Doctors treating people with dementia say they hope to see more research on the exact relationship between depression and later decline of brain function.