A recent article reported in Medical News Today confirms what I have suspected for some time: stress apparently is a co-factor for memory loss associated with Alzheimer's Disease.
A study being being published in the September 1st issue of Biological Psychiatry was designed to explore the relationship between mutations of the APOE gene (also called allele) and cortisol levels. It is known that the a4 variant of the APOE gene contributes to the risk for memory loss related to Alzheimer's Disease, as do high circulating levels of cortisol, associated with high stress levels.
The article is "The Effects of Prolonged Stress and APOE Genotype on Memory and Cortisol in Older Adults" by Guerry M. Peavy, Kelly L. Lange, David P. Salmon, Thomas L. Patterson, Sherry Goldman, Anthony C. Gamst, Paul J. Mills, Srikrishna Khandrika and Douglas Galasko. It appears in Biological Psychiatry, Volume 62, Issue 5 (September 1, 2007), published by Elsevier.
The study results showed that "low-stress subjects performed better than high-stress subjects on delayed recall of stories, word lists, and visual designs. APOE-epsilon4-negative subjects obtained better scores than epsilon4-positive subjects on immediate and delayed recall of visual designs."
The study also showed worse memory and higher cortisol concentrations in the high stress, epsilon4-positive group. The authors concluded that the findings indicate "prolonged exposure of older, nondemented individuals to stress in the presence of an epsilon4 allele leads to memory decline." They hope to do further studies to learn whether stress and this gene mutation interact to increase the risk of developing Alzheimer's disease in the first place.
I was not surprised to read about this, as I have been aware of several cases of Alzheimer's Disease that seemed to come on rather suddenly after a highly stressful situation. The mother-in-law of a friend of mine, who seemed totally normal not long before her husband died, became almost completely demented by the end of the following year. My husband's grandmother didn't show any overt memory loss or signs of Alzheimer's until not long after her only son accidentally (we think) shot himself in the head and was stricken blind as a result.
My father's mental state was pretty normal (other than his usual problems with depression) until a year or so after major heart surgery, which must have been stressful for both mind and body. I wonder to this day whether he would have been better off dying of heart failure at 86 rather than living to 92, with the last three years lived in an ever-increasing fog of memory loss, loss of skills, loss of comprehension, and loss of personality.
My mother-in-law now seems to be in the middle stages of Alzheimer's Disease; but her forgetfulness started not long after her own mother died in the nursing home of complications from Alzheimer's Disease. My mother-in-law had been under tremendous stress for a number of years before her mother's death, when her mother was still living in a senior citzen's apartment building. She went there every day, made sure her mother ate, bathed her, brought her over to her own home to entertain her, dealt with her mother's temper tantrums as she worsened and showed personality changes, etc. Her mother died not that long after entering the nursing home because she broke her hip, which tipped her over the edge into incoherence after the hip was operated on. This was still more stress for my mother-in-law, who developed shingles at this time, another indication of the body's reaction to stress, which lowers the immune system response.
While further studies are planned, it makes sense to me that if you have any Alzheimer's Disease in your family, that you should avoid stress as much as possible. While we don't know whether the development of AD can be prevented or delayed by reducing stress, it sure couldn't hurt.
Of course, as a hypochondriac, you will probably now get stressed out worrying whether your stress levels are leading to early Alzheimer's Disease. This will be self-defeating, so go meditate or something! And a little yoga might help too.