New research from Sweden suggests that the personality dimension is connected to who ultimately suffers from late-in-life dementia.

What are the odds that you, or a loved one, will develop Alzheimer’s disease? What, if anything, can be done to lower the odds of its onset? While such questions are unanswerable, at least for the moment, intriguing new research suggests people with a specific personality trait are more likely to ultimately suffer from this insidious end-of-life disease.

In a sample of 800 Swedish women who were tracked for 38 years, a high degree of neuroticism, measured at midlife, was associated with increased risk of Alzheimer’s disease at old age.

This association was most pronounced among those who also reported ongoing high levels of stress in their lives. However, that may be something of a chicken-and-egg distinction, as people with high degrees of neuroticism—which includes those high in anxiety, depression, or guilt—may tend to find life more stressful than most because of the ways they react to its inevitable challenges.

"Personality may influence the individual’s risk of dementia through its effect on behavior and lifestyle," they write, noting that neurotic people may be more prone to obesity and alcohol abuse.

“The number of people with dementia disorders is expected to increase dramatically with global aging,” a research team led by Lena Johansson of the University of Gothenburg writes in the journal Neurology. “It is therefore important to identify risk and protective factors for these disorders.”

To that end, the researchers examined data on 800 participants in the Prospective Population Study of Women in Gothenburg, Sweden. The women, who were born between 1914 and 1930, registered for the study in 1968. That year, they completed the Eysneck Personality Inventory, which was used to measure their level of neuroticism, as well as whether they tended toward introversion or extraversion.

On Eysneck’s inventory, people high in neuroticism tend to suffer from one or more of the following: excessive fear and anxiety, feelings of guilt, low self-esteem, and/or depression.

At that initial screening, and again during follow-ups in 1974, 1980, 2000, and 2005, participants were asked whether they had experienced any periods of stress of one month or longer due to their life circumstances. Those who answered that they had experienced “constant stress for the last five years,” “several periods of stress during the last five years,” or “constant stress during the last year” were placed in the “distressed” category.

“We found that a higher degree of neuroticism in midlife was associated with higher incidence of late-life Alzheimer’s Disease,” the researchers report. They add that this association diminishes after taking individuals’ stress levels into account.

“It is possible that neuroticism makes the individual more vulnerable to stressors and distress,” they write, “which leads to later development of dementia.”

Johansson and her colleagues offer several possible reasons for this association. “Personality may influence the individual’s risk of dementia through its effect on behavior and lifestyle,” they write, noting that neurotic people may be more prone to obesity and alcohol abuse.

In addition, they note, neuroticism has been linked with changes to the brain, including “an increased amount of neuro-fibrillary tangles”—a key marker of Alzheimer’s disease.

While basic personality traits can be difficult to alter, these results provide another reason why people plagued by neurotic tendencies should not hesitate to seek professional help.

If therapy, a meditation regime, or some other practice can help you ride life’s waves in a calmer way, you won’t only be more content in the short run. You may also increase your chances of retaining strong mental health into old age.