April 8th, 2008
09:44 AM ET

Alzheimer's: Another clue

By Dr. Sanjay Gupta
Chief Medical Correspondent

Wouldn't it be great to know if you were likely to develop Alzheimer's disease? I think about it all the time, especially when I forget something, lose my keys or lose my train of thought, which really seems to happen more and more lately. Truth is, everyone does that from time to time, and it often has no relationship to developing dementia. But researchers think they have found something that may serve as a warning sign. Depression. While it has long been believed that people with Alzheimer's become depressed because of the mind-robbing effects of the disease, there is now some evidence to suggest that it is, in fact, the other way around. Depression may be a risk factor for Alzheimer's.

After tracking 917 retired Catholic priests and nuns, researchers found those with symptoms of depression at the beginning of the study were more likely to develop Alzheimer's disease. (read study)   A different study found that those with depression were 2.5 times more likely to develop Alzheimer's and if you developed depression before the age of 60, you were actually 4 times more likely to develop it.

The big question, of course, is why.  Well, after doing some digging, there is no easy answer.  However, consider this: People with depression often release lots of cortisol because of the stress of their depression, and it is believed that cortisol by itself could cause damage to the vital connections in the brain that are responsible for memory.

There is no question that as our population ages, more people than ever will develop Alzheimer's disease. Besides better treatments, one of the biggest goals for researchers is earlier detection. 

As a neurosurgeon, I am fascinated by this and I am curious:  If you know, or have known anyone with Alzheimer's disease, did you see any early clues that signaled future Alzheimer's disease?

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About this blog

Get a behind-the-scenes look at the latest stories from CNN Chief Medical Correspondent, Dr. Sanjay Gupta, Senior Medical Correspondent Elizabeth Cohen and the CNN Medical Unit producers. They'll share news and views on health and medical trends - info that will help you take better care of yourself and the people you love.