Study: Stress Linked to Dementia

Women who reported more stressors experienced more distress over the course of their lives and higher rates of dementia.


Problem: Enormously stressful events, like seeing combat in the military, can continue to affect people for years, through post-traumatic stress disorder. But though regular life isn’t always stressful to such a magnitude, it’s not all hugs and puppies either. Some common stressors that are just a part of life—losing loved ones, relationship struggles, pressure at work—can take their toll, too.  A study published recently in the journal BMJ Open looks at the link between the burden of these common stresses and late-in-life brain diseases like dementia.

Methodology: This was a long-term longitudinal study of 800 women in Sweden, starting in 1968, and following up with them periodically—in 1974, 1980, 1992, 2000, and 2005.  The women ranged in age (at the first evaluation in 1968) from 38 to 54 years old. A psychiatrist examined the women and rated several common stressors, including divorce, illness in loved ones, problems with their own or their husbands’ work, or having a limited social network.

Over the years, researchers looked at whether the women experienced any periods of distress, and noted changes in their behavior and intellect. For those who developed dementia, they noted the age of onset, and how the disease progressed. They also made sure to control for other factors, ranging from socioeconomic background to family history of mental illness to smoking.

Results: Between the initial assessment in 1968 and 2006, 19.1 percent of the women developed dementia. The number of stressors women reported experiencing in 1968 was associated with long-lasting distress over the years, as well as higher rates of Alzheimer’s disease and other types of dementia later in life.

“Increased distress could not completely explain the association between midlife stressors and dementia,” the study reads. “One reason for this is that individuals respond differently to psychosocial stressors. Thus, biological responses may develop as a reaction to psychosocial stressors also in individuals who do not experience or report increased distress in association to the stressor.”

Implications: The study offers some potential biological reasons for this link—previous research has shown that stress can affect learning and memory, damage the hippocampus, and increase the rate of hypertension and cardiovascular disease, all things that have been linked to dementia. The researchers note that more studies would be necessary to cement a link between stress and dementia, but it does seem from the data that stress experienced in mid-life can have long-term consequences. Knowing that, could, of course, make the stress worse, if you start to feel stressed about being stressed.

The study, "Common psychosocial stressors in middle-aged women related to longstanding distress and increased risk of Alzheimer's disease: a 38-year longitudinal population study," was published in the journal BMJ Open.