November 29, 2023
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Some personality traits, like being extraverted or conscientious, may help protect people from developing dementia, research shows. Neuroticism may increase the risk.
People who are extroverted or have high levels of conscientiousness appear to be at lower risk for dementia than those with personality traits like neuroticism, according to new research that examined the ways behavior affects cognitive decline.
About 5.8 million people in the United States have Alzheimer's disease or related dementias, according to estimates from the U.S. Centers for Disease Control & Prevention. That figure is expected to rise to about 14 million people by 2060, primarily among those over 65.
Research on the causes of dementia historically has focused on the impacts of aging, family history, heart disease and previous head injuries. But scientists are increasingly interested in determining whether behavioral features are related to the development of dementia.
Researchers at the University of California, Davis and Northwestern University teamed up to analyze eight studies linking different personality types to increased dementia risk. They examined data from more than 44,000 people, including 1,703 who developed dementia.
The studies all looked at the "big five" personality traits — conscientiousness, extraversion, openness to experience, neuroticism and agreeableness. They also took into account subjective well-being and how it connects to clinical symptoms of dementia. The data came from a combination of personality tests, cognitive performance measures and brain autopsies.
The analysis found that people who were open to experiences, agreeable and satisfied with their lives had lower rates of dementia. Personality traits like neuroticism and negative affect were linked to higher rates of the illness. Likewise, people who scored low on extraversion, conscientiousness and positive effect were more likely to develop dementia.
Notably, the researchers found no link between personality traits and the appearance of actual signs of dementia in the brains of people after death.
"This was the most surprising finding to us," said researcher Emorie Beck, an assistant professor of psychology at UC Davis. "If personality is predictive of performance on cognitive tests but not pathology, what might be happening?"
Beck said the research review was intended to sharpen insights into how personality shapes behaviors, which in turn may impact how people cope with dementia symptoms. People with more negative personality traits may be less resilient to the effects of disease, leading to more severe impairments as they progress. Past studies done by the researchers found that some people with clear brain pathology don't show significant deficits on cognitive tests.
Conscientiousness — the tendency to be responsible, organized, hard-working and ethical — appears to be more protective against dementia as age increases, the researchers found. Age, gender and educational attainment had no significant effects on how personality, dementia risk and brain pathology were related.
Examining different connections between personality traits and dementia may help prepare people to manage symptoms more effectively.
"If those links hold up, then targeting personality traits for change in interventions earlier in life could be a way to reduce dementia risk in the long term," Beck said.
The work done by Beck and her colleagues was supported by grants from the National Institute on Aging, which is part of the National Institutes of Health.
A previous study supported by the NIA reached similar findings on how some personality traits may relate to dementia risk. That study also found supporting evidence in brain tissue samples, which were examined to look for hallmarks of Alzheimer's disease. High scores for neuroticism and low scores for conscientiousness were both tied to physical markers of disease in the brain, although the study could not explain the causes of these connections.
Another NIA-backed study looked at long-term links between personality traits in high school students and the risk of dementia five decades later. The students who had an energetic disposition, vitality and a high level of physical activity were less likely to develop dementia. The same was true for students who showed calmness and maturity. Traits like social sensitivity, sociability and leadership — qualities often associated with extraverts — did not appear to be linked with dementia diagnoses one way or the other in that study.
Beck said more research is needed to expand knowledge about the associations between personality and dementia. The researchers aim to better understand why some people with obvious signs of brain pathology related to dementia are better able to continue their lives with minimal impairment.
