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Are certain personality traits associated with a lower risk of dementia? Eloisa Ramos/Stocksy
  • People whose personalities lean toward conscientiousness, extraversion, and positive affect are less likely to develop dementia, according to a new meta-study.
  • A reduction in the risk of dementia grows stronger with age for people with such personalities, says the meta-study.
  • Conversely, people whose personalities are more characterized by neuroticism and negative affect are more likely to develop dementia eventually.
  • While the researchers found the associations between personality type and dementia to be strong, autopsies of study participants did not find any suggestion of a link between personality and pathology.

A new meta-study — or study of other studies — from researchers at the University of California at Davis (UC–Davis) explores the effect one’s personality has on one’s risk of developing dementia. Specifically, the study investigates possible associations between psychology’s Big Five personality traits and eventual dementia.

People whose personalities are described in the Big Five hierarchy as predominantly conscientious, extroverted, and having a positive affect are less likely to develop dementia, finds the study. People whose personalities are largely characterized by neuroticism and negative affect are significantly more likely to do so.

The Big Five is a system that encompasses the range of human personalities, with people ideally possessing a balance of personality types. Having too much of one or lacking another, can be problematic.

The Big Five personality traits are:

  • Openness — a personality that welcomes new experiences.
  • Conscientiousness — a personality characterized by a motivated, perfectionist work ethic.
  • Extraversion — a sociable, outgoing personality.
  • Agreeableness — a personality that prioritizes getting along with others.
  • Neuroticism — a personality that is insecure and often overly emotional.

In the meta-study, researchers examined two traits that are not explicitly part of the Big Five: positive affect and negative affect. Positive affect is most closely associated with extraversion, though it can also be an element in other personality types. Negative affect is similar, although most closely tied to neuroticism.

While the meta-study found strong associations between personality type and dementia, no significant evidence of brain pathology was identified that linked the two, suggesting some other connection.

The meta-study included an analysis of data from eight published studies involving 44,531 people. Each individual was measured for personality type(s), and all underwent brain pathology examination after death during autopsies.

The study also found that the association between personality types and the risk of dementia grew stronger with age.

The study is published in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association.

Previous work has explored linkages between personality type and the chances of developing dementia. However, the study’s first author, Dr. Emorie Beck of UC–Davis, said: “Many of those studies had been conducted so differently, sometimes using really complex techniques, that it’s hard to compare them.”

“We wanted to take a step back and see if we ask a basic question — ‘Does your personality now predict later dementia risk and neuropathological burden?’ — using as much data as we could possibly get our hands on.”

– Dr. Beck

”We saw this as a chance,” she explained, “to then take the data we’ve gathered to do a number of follow-up studies where we dig in more to ask harder questions; e.g., what are the mechanisms that link personality traits to dementia?”

“We found that a person’s personality traits are not related to whether (or not) they develop the physical pathology that is characteristic of [Alzheimer’s Disease Related Dementias] (ADRD), but that it is related to those clinical manifestations and diagnostic risk,” said Dr. Beck.

“This is good news. Even if we can’t necessarily prevent the disease itself, we can possibly mitigate the clinical signs of disease and reduce our odds of cognitive impairment.”

– Dr. Beck

Dr. David A. Merrill, Ph.D., is a geriatric psychiatrist and director of the Pacific Neuroscience Institute’s Pacific Brain Health Center in Santa Monica, CA. He was not involved in the study.

He suggested people with high conscientiousness, extraversion, and a positive affect are “well-suited to adopt what we’ve come to know as common-sense measures for healthy aging.” These include “regular exercise, healthy diet, good sleep, low stress, social and cognitively stimulating activities.”

“There may be a cumulative benefit of conscientious living over time. Both by supporting healthy behaviors, but also in avoiding potentially harmful habits or events like drinking to excess or having a head injury from thrill-seeking activities.”

– Dr. Merrill

Dr. Claire Sexton, Senior Director of Scientific Programs and Outreach at the Alzheimer’s Association, noted that multiple plausible pathways between personality and dementia risk have been proposed. She listed “low levels of physical activity, high alcohol consumption, poor diet, and smoking, all of which have also been associated with increased risk of dementia.”

Underscoring the complexity of sorting out such mechanisms, Dr. Sexton pointed out that two traits, neuroticism, and conscientiousness, have been associated with amyloid and tau neuropathology in other studies, and conscientiousness has also been linked with inflammatory biomarkers.

Professor of Geriatrics at Florida State University, Dr. Anthonio Terraciano, Ph.D., pointed out that some other studies have linked personality traits of dementia, referring to the meta-study’s finding in this regard as being “contrary to some recent in vivo research.”

In his own work, he has found neuroticism and conscientiousness tied to neurodegeneration and astrogliosis. “There is also some evidence of an association between neuroticism and white matter hyperintensities.”

Dr. Terraciano cautioned, “I am surprised by the conscientiousness and age interaction. We have not found such interaction in other samples.”

Still, suggested Dr. Beck, “Our guess is that people who are higher in conscientiousness have probably been high in that for a while, so the older they get, the more those positive health behaviors have a chance to accrue.”

“It would be helpful for individuals to understand their own personalities as they age so they have better odds of adopting healthy habits and avoiding harmful events that lead to dementia.”

– Dr. Merrill

His statement ties in with an interesting suggestion from Dr. Beck: “The organization, industriousness, and planning that characterizes those high in conscientiousness may be helpful for them to continue to navigate their environments, even when their cognitive function may be declining.”

“Our thinking is that all these forces are sort of working together to support the increasing protective effect of conscientiousness across the lifespan,” Dr. Beck proposed.