Conscientious personalities less at risk of dementia diagnosis

• Link to: Northwestern Now Story

• Difference not linked to physical damage to brain tissue of dementia patients assessed at autopsy
• More likely linked to how certain personality traits help people navigate dementia-related impairments
• Targeting personality traits with interventions earlier in life could be a way to reduce dementia risk in the long term

CHICAGO --- People with personality traits such as conscientiousness, extraversion and positive affect are less likely to be diagnosed with dementia than those with neuroticism and negative affect, according to a new analysis by researchers at Northwestern University and the University of California, Davis.

“We’ve seen in previous research that if someone is higher in neuroticism, they have higher odds of being clinically diagnosed with dementia, whereas those higher in conscientiousness have lower odds of developing dementia,” said senior author Eileen Graham, associate professor of medical social sciences at Northwestern University Feinberg School of Medicine. “However, those clinical diagnoses are typically based on assessments of cognition. We wondered how personality traits might be related to clinically diagnosed dementia compared to dementia based on neuropathology markers assessed at autopsy.”

The difference was not linked to physical damage to brain tissue found in dementia patients, but more likely to how certain personality traits help people navigate dementia-related impairments, the study found.

“This was the most surprising finding to us,” said Emorie Beck, assistant professor of psychology at UC Davis and first author on the paper who conducted part of the research while she was a postdoctoral researcher at Northwestern. “If personality is predictive of performance on cognitive tests but not pathology, what might be happening?”

One explanation is that some personality traits could make people more resilient to the damage caused by diseases such as Alzheimer’s. People with higher levels of some traits may find ways, whether they are aware of it or not, to cope with and work around impairments. Other work by members of the study team has shown that some people with quite extensive pathology can show little impairment on cognitive tests.

The study will be published Nov. 29 in Alzheimer's & Dementia: The Journal of the Alzheimer's Association.

Previous studies have tried to establish links between personality traits and dementia, but these were mostly small cohorts that represented only specific populations, the scientists said.

“We wanted to leverage new technology to synthesize these studies and test the strength and consistency of these associations,” Beck said.

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, she said.

“Neuroticism is related to dementia decline, and people with neuroticism are more prone to anxiousness, moodiness and worry whereas conscientious people are more likely to exercise, make and go to preventive health appointments and drink less,” Graham said. “So maybe that’s where an intervention might be useful to improve someone’s health behaviors for better health outcomes.”

The ‘Big Five’ personality traits

Graham’s work focuses on individual differences factors that are associated with health outcomes in older adulthood. Her research group specifically focuses on the development of the “Big Five” personality traits (conscientiousness, extraversion, openness to experience, neuroticism and agreeableness) over the life course, and how these traits may influence physical health, onset of disease, cognitive decline and mortality.

The scientists analyzed data from eight published studies including more than 44,000 people, of whom 1,703 developed dementia. They looked at measures of the “big five” personality traits and subjective wellbeing (positive and negative affect, and life satisfaction) compared to clinical symptoms of dementia (performance on cognitive tests) and brain pathology at autopsy.

Personality is typically thought to be linked to dementia risk through behavior, the scientists said. For example, people who score high on conscientiousness may be more likely to eat well and take care of their health, which accumulates as better health in the long-term.

The researchers found that high scores on negative traits (neuroticism, negative affect) and low scores on positive traits (conscientiousness, extraversion, positive affect) were associated with a higher risk of a dementia diagnosis. High scores on openness to experience, agreeableness and life satisfaction had a protective effect in a smaller subset of studies.

The researchers also looked at other factors that could moderate the relationship between personality and dementia risk and neuropathology, including age, gender and educational attainment.

“We found almost no evidence for effects, except that conscientiousness’s protective effect increased with age,” Beck said.

Many factors contribute to the development of dementia. Among those that aren’t directly related to genetics, this study is a first step in teasing out the associations between personality and dementia. The scientists plan to continue to expand the work, including looking at people who show little impairment in the face of a lot of pathology. They also hope to look at other everyday factors that may play a role in developing dementia.

Coauthors are: Tomiko Yoneda, UC Davis and Northwestern; Daniel Mroczek, Northwestern; Bryan James, David Bennett and John Morris and Jason Hassenstab, Washington University School of Medicine, St. Louis; Mindy Katz and Richard Lipton, Albert Einstein College of Medicine, the Bronx.

The work was supported by grants from the National Institute on Aging (R01-AG067622 and R01-AG018436)