In their report, which was published in the International Journal of Geriatric Psychiatry, the team noted that the findings were specific to women who experience chronic stress. This could also explain the disproportionate rates of dementia in women.
“A normal stress response causes a temporary increase in stress hormones like cortisol, and when it’s over, levels return to baseline and you recover,” explained lead author Cynthia Munro.
“But with repeated stress, or with enhanced sensitivity to stress, your body mounts an increased and sustained hormone response that takes longer to recover.”
Stressful life experiences linked to poor memory, learning
Munro and her team used data from the National Institute of Mental Health Epidemiologic Catchment Area Study, as well as its follow-up reports. The team looked at data from Wave 3 comprising follow-up interviews from 1993 to 1996. In particular, the team collated reports of those who suffered stressful life events – such as marriage, divorce and death – and traumatic events, including combat, rape and mugging. From these parameters, the team was able to obtain data from 909 participants.
In the original study, around half of both male and female participants reported at least one stressful life experience in the year before their visit.
Wave 3 – and subsequently, Wave 4 – also tested the participants for learning and memory. The test involved having the participants recall a set of words immediately after these were spoken and after 20 minutes.
For their Wave 3 visit, the participants were able to correctly identify an average of 15 words from the test. But by Wave 4, this dropped to seven words. (Related: Understanding the medical differences between Alzheimer’s and dementia.)
From the findings of the follow-up study, the Johns Hopkins team then measured these decreases in test performance between Waves 3 and 4. They compared these with the participants’ reports of stressful life experiences and traumatic events to see if there was any association between those factors and cognitive decline.
Brain responds to stress and trauma differently
The researchers found that women who reported experiencing more stressful experiences performed poorly in Wave 4’s tests — an indication of cognitive decline. In comparison, those who did not report stressful life experiences performed much better in their last test.
It is worth noting the finding did not exist for women who reported traumatic events. According to Munro, this could indicate that distinct events such as trauma register differently in the brain than ongoing stress.
The condition, which Munro called “chronic stress” can negatively affect the body’s ability to respond to stress.
Adjusting stress response is key
While stress reduction still has not been given enough focus as a possible contributing factor to dementia, the team pointed out that it might be worth exploring stress management techniques as a way to delay or prevent the disease from developing.
“We can’t get rid of stressors, but we might adjust the way we respond to stress,” Munro added.
The researchers were not able to see the same association between cognitive decline and experiencing either stressful life experiences or traumatic events in men. While the sex-based differences aren’t huge, they still point to stress as a possible cause of the cognitive decline in women who suffer from Alzheimer’s and other dementia-type diseases.
In a statement, Munro and her team said that a follow-up study is necessary to learn if the minute differences they spotted would add up and subsequently have an important effect over time.
Learn more about dementia and other neurodegenerative diseases at Brain.news.