Do big personality changes predict Alzheimer’s? Not necessarily, new study says 

hand putting a missing piece inside a wooden puzzle in the shape of a brain

For decades, scientists have been trying to identify early signs of memory impairment in adults in an attempt to screen for or even slow down the onset of cognitive decline. Some clinicians believe that major personality changes, such as an increase in neuroticism, could be a canary in the coal mine for Alzheimer’s disease and other types of dementia.

But one sociologist is telling those clinicians: Not so fast.

In a recent study published in Nature Scientific Reports, Katsuya Oi, an associate professor of sociology at Northern Arizona University, found that major personality changes happen for a whole host of reasons and don’t necessarily predict memory impairment.

“Clinicians have started to look at how personality changes coincide with memory impairment, and I get why—it’s a cheap, quick way to look for signs of Alzheimer’s,” Oi said. “The findings are exciting, but they are misleading without sufficient attention to all the other factors that can facilitate personality changes: loss, work stress, family stress, body changes and other things that millions of us experience as we age.”

For the study, Oi and his colleague, Cleothia Frazier of Pennsylvania State University, used data collected from more than 12,000 Americans aged 50 and older as part of a Health and Retirement Study conducted from 2006 to 2020. They set out to analyze how changes in the so-called “Big Five” personality factors—neuroticism, openness, extraversion, agreeableness and conscientiousness—occur alongside stressful life changes and memory impairment.

Their findings were surprising and nuanced. On average, older adults—whether memory impaired or not—showed small but significant decreases across all five personality traits over time. That pattern is consistent with existing research suggesting that people’s personalities tend to become less pronounced with age and that people tend to become more socially and emotionally withdrawn as they grow older.

Yet, Oi said, some individuals showed greater personality changes. Some experienced a decrease in their ability to regulate emotions, suggesting increased neuroticism. Others had more difficulty planning and acting toward long-term goals, suggesting a decrease in conscientiousness.

To the researchers’ surprise, they found that these changes, known to reflect impairments in the prefrontal cortex and limbic system, were not primarily driven by memory impairment. Instead, they were strongly associated with life stressors. Stress-related events such as loss, financial difficulties or health struggles accounted for 25-35% of changes in neuroticism over an eight-year period.

Oi said clinicians have started linking personality changes to memory impairment because it’s proven to be an accessible, and thus promising, way to screen for potential Alzheimer’s cases on a large scale. But his and Frazier’s findings call into question how often personality changes in later life actually signal impairment.

“We are not refuting the relationship between increased neuroticism and the early stages of dementia or Alzheimer’s,” Oi said. “We’re just the first to point out that not all older adults who have increased neuroticism are in the early stages of cognitive decline. There are a lot of things that happen in life that affect our brains and our personalities at the same time. Everyone knows that it’s hard to function as the person you know you are when you’re stressed.”

For Oi, the findings underscore the importance of limiting stress in our society. That starts with tackling inequality, as multiple studies show that people who face poverty, discrimination or health issues take on a disproportionate amount of stress.

“Imagine working into your 70s or 80s to make ends meet or losing sleep over hospital bills,” Oi said. “These are inhumane stressors that not only affect day-to-day life but also increase risks of cognitive decline. To reduce stress, we need to address systemic inequalities.”  

Oi recommended that medical professionals work with patients and their caregivers to contextualize observed personality changes before jumping to conclusions about dementia. Whether pathological or not, people are often unaware of changes in themselves. A holistic approach to cognitive health is essential not only for early screening and detection, he said, but also for delaying the onset of impairment. If stress is causing people to feel unlike themselves, that should be the first issue addressed, rather than the personality changes themselves.

“Personality changes indicate something tumultuous going on, some tension between life and self,” Oi said. “That could be Alzheimer’s disease or dementia, or it could be something else. That something else, if unchecked, can turn clinical.”

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Jill Kimball | NAU Communications
(928) 523-2282 | jill.kimball@nau.edu

NAU Communications