Thinker in painThis article discusses the link between depression and the onset of dementia and alzheimer’s disease.  Sapolsky’s work shows that stress can lead to a deterioration in the hippocampus which then leads to more stress so you get an acceleration of aging.  So given that mood deteriorates with stress and conversely, mood improves with stress reduction techniques, such as acupuncture, I would think that the two would be quite closely related.

They are careful not to draw any firm conclusions from the cited studies.

Does Depression Contribute to Dementia?

By JUDITH GRAHAM

A large body of research has linked late-life depression to social isolation, poorer health and an increased risk of death. Now, a new study finds that depression is associated with subsequent vascular dementia and Alzheimer’s disease, conditions poised to expand dramatically with the aging population.

The report, published on Wednesday in the British Journal of Psychiatry, is a meta-analysis of 23 previous studies that followed nearly 50,000 older adults over a median of five years. The researchers found that depressed older adults (defined as those over age 50) were more than twice as likely to develop vascular dementia and 65 percent more likely to develop Alzheimer’s disease than similarly aged people who weren’t depressed.

“We can’t say that late-life depression causes dementia, but we can say it likely contributes to it,” said Meryl Butters, an associate professor of psychiatry at the University of Pittsburgh School of Medicine and a co-author of the paper. “We think depression is toxic to the brain, and if you’re walking around with some mild brain damage, it will add to the degenerative process.”

In terms of absolute risk, she said, the data suggest that 36 of every 50 older adults with late-life depression may go on to develop vascular dementia, while 31 of every 50 seniors with a history of depression may eventually be diagnosed with Alzheimer’s.

Previous research has shown that a history of depression is linked to a doubling of the risk that someone will end up with Alzheimer’s disease. But this is the first analysis to demonstrate an even stronger association with vascular dementia, a condition caused by strokes or other interruptions to blood flow in the brain.

 

That does not mean a causal relationship between depression and dementia has been established; it hasn’t. Nor is there any solid evidence yet that forestalling depression will prevent dementia.