Two personality traits, neuroticism and conscientiousness, were connected to the signature buildup of Alzheimer’s disease hallmarks of amyloid and tau in the brain, according to a team of researchers led by NIA-supported scientists. To reach these findings — published in Biological Psychiatry — the team tracked brain scans and personality test results from thousands of participants in long-term studies of aging.
Several previous smaller studies had examined the growing evidence for links between dimensions of personality and risk for Alzheimer’s neuropathology such as the signature buildups of amyloid and tau in the brain. For this new study, the researchers focused on neuroticism, a propensity for negative feelings such as anxiety, self-doubt, and depression; and conscientiousness, a trait of people who tend to be self-disciplined, responsible, organized, and focused on achieving goals.
The researchers analyzed data from the NIA Intramural Research Program’s Baltimore Longitudinal Study of Aging. With the goal of obtaining stronger readings on potential connections, they also performed a larger meta-analysis of 12 other studies that included personality and Alzheimer’s pathology data from more than 3,000 participants. Personality was measured with a commonly used five-factor assessment.
The personality data were then compared to positron emission tomography (PET) brain scans, a form of brain imaging technology that enables scientists and clinicians to visualize and quantify amounts of amyloid and tau neuropathology in living clinical trial participants. Prior to PET technology, researchers could only measure these neuropathological signs in autopsy samples postmortem.
In the combined data sets, the scientists found more amyloid and tau deposits in participants who scored higher in neuroticism and lower in conscientiousness. The researchers are unsure of the explanations behind these results but want to pursue future expanded studies in this realm, especially whether better health habits and outcomes in people with lower neuroticism and higher conscientiousness may drive these findings. They also note that other previous studies have shown parallels between mental outlook and brain health as we age, including more cognitive resilience to dementia-related pathology in people who scored higher in psychological tests measuring a firm sense of purpose in their lives.
The researchers see this study as evidence that personality is related to dementia-associated pathology before outward symptoms of cognitive impairment become apparent, and another step in investigating these intriguing mind/body connections in Alzheimer’s and other neurological diseases. For future studies, they hope to explore if incorporating considerations of patient personality and/or mental health could be another puzzle piece in the search for better early identification of high-risk people who might benefit from early treatments to delay or prevent the emergence of harmful neuropathology.
This research was supported by the NIA Intramural Research Program and by NIA grants R01AG068093 and R01AG053297.
Reference: Terracciano A et al. Personality associations with amyloid and tau: Results from the Baltimore Longitudinal Study of Aging and meta-analysis. Biological Psychiatry. 2021;S0006-3223(21)01566-3. doi:10.1016/j.biopsych.2021.08.021