24 Oct 2019

Changes in personality often become apparent just before dementia arises, but could certain traits in early life associate with dementia risk decades later? Yes, according to a study published October 16 in JAMA Psychiatry. Researchers led by Benjamin Chapman of the University of Rochester Medical Center in New York and Susan Lapham of the American Institutes for Research in Washington, D.C., cross-referenced scores from personality tests taken by thousands of high school students in 1960 with their current medical records. They reported that teens with higher levels of certain adaptive traits—vigor, calmness, and maturity—were less likely to have developed dementia by age 70. How these agreeable personality traits would protect against dementia remains unclear, but the results suggest that personality may be an independent risk factor for dementia, rather than merely a consequence of neurodegenerative pathology.

Certain undesirable personality traits—such as neuroticism, impulsivity, and lack of conscientiousness—can appear in the years preceding a dementia diagnosis, but those attributes can also intensify during the symptomatic stages of the disease (Yoneda et al., 2016; Tautvydaité et al., 2017; Terracciano et al., 2019). This complicates efforts to understand whether personality quirks arise as a consequence of neurodegeneration, or are independent risk factors for those diseases.

To address this question, the researchers accessed personality data gathered from Project Talent—a massive study of high school students in the United States in 1960. At the time, more than 377,000 students participated in two days of tests and questionnaires, including a 150-item personality test that quantified 10 personality traits, such as sociability, impulsivity, leadership, vigor, calm, maturity, and self-confidence. More than 82,000 of those participants were recently identified in the Medicare claims database, allowing researchers to link their attributes in 1960 to their current health. Previously, the researchers tied adolescent personality traits in this cohort to all-cause mortality, and linked some teenage cognitive aptitudes to dementia risk (Oct 2018 news on Huang et al., 2018). 

For this study, they asked whether adolescent personality traits associated with dementia diagnosis. Of the 82,232 participants, 2,543 (3.1 percent) met the criteria for dementia between 2011 and 2013, when they averaged 69 years of age. Each of the 10 personality traits was recorded as a range, allowing the researchers to correlate dementia risk with each standard deviation from the mean of that trait. A 7 percent lower risk of dementia for each standard deviation above the mean popped up for “vigor.”

What was 1960s vigor, a reader may ask? The measure comprised vitality, energy, and general activity level. It offered protection independently of socioeconomic status, which was defined by the education, income, and property ownership of each participant’s parents in 1960. Two other personality traits—calm and maturity—afforded about a 10 percent protection from dementia, but only for those with above-average socioeconomic status.

The researchers also found that people who possessed a combination of positive traits—social sensitivity, calm, tidiness, culture, and maturity—had a lower dementia risk. Protection afforded by this so-called “general personality factor” increased with higher socioeconomic status. A calm personality—also described as low neuroticism score—might reflect healthier physiological responses to chronic stress. Low socioeconomic status can cause chronic stress, and even a calm personality may be unable to offset a high degree of strain that comes with poverty, the researchers speculated.

The findings cast certain adolescent personality traits as risk factors for dementia by age 70. The authors speculated that vigor could be a proxy for physical activity and enthusiastic engagement with life. If these characteristics continue throughout life, they could hedge dementia risk, they proposed. “While social class may shape the specific type or content of one’s life activities, the beneficial nature of energetic enthusiasm appears to be constant across the socioeconomic spectrum,” they wrote.

“These results are certainly consistent with the current literature linking personality as a behavioral/lifestyle indicator of dementia risk in older adults,” commented Janet Duchek of Washington University in St. Louis. “This study provides further evidence that these personality traits may serve as important proxies for various protective lifestyle and health behaviors over the course of the lifespan, such as engagement in physical, cognitive, and social activities.”—Jessica Shugart

Comments

1. • Steve Barger
     University of Arkansas for Medical Sciences
   • Posted: 29 Oct 2019

   This is quite intriguing. I wonder if the association might have anything to do with APOE genotype? I'm rather surprised that the study did not include analysis of that variable. ApoE isoforms have been shown to impact personality traits when expressed in mice, and the direction of difference is consistent with the findings by Chapman et al., i.e., ApoE4 expression is associated with greater indices of impulsivity, perseveration, and premature responses (Meng et al., 2015; Reverte et al., 2016). I have not seen these personality traits confirmed in human subjects, but have heard anecdotal reports by psychiatrists.

   References:

   Meng FT, Zhao J, Fang H, Liu YJ. The influence of chronic stress on anxiety-like behavior and cognitive function in different human GFAP-ApoE transgenic adult male mice. Stress. 2015 Jul;18(4):419-26. Epub 2015 May 4 PubMed.

   Reverte I, Peris-Sampedro F, Basaure P, Campa L, Suñol C, Moreno M, Domingo JL, Colomina MT. Attentional performance, impulsivity, and related neurotransmitter systems in apoE2, apoE3, and apoE4 female transgenic mice. Psychopharmacology (Berl). 2016 Jan;233(2):295-308. PubMed.

   View all comments by Steve Barger

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References

News Citations

1. Intelligence Matters More for Brain Reserve, but Education Helps 12 Oct 2018

Paper Citations

1. Yoneda T, Rush J, Berg AI, Johansson B, Piccinin AM. Trajectories of Personality Traits Preceding Dementia Diagnosis. J Gerontol B Psychol Sci Soc Sci. 2016 Mar 4; PubMed.
2. Tautvydaitė D, Antonietti JP, Henry H, von Gunten A, Popp J. Relations between personality changes and cerebrospinal fluid biomarkers of Alzheimer's disease pathology. J Psychiatr Res. 2017 Jul;90:12-20. Epub 2017 Feb 4 PubMed.
3. Terracciano A, Sutin AR. Personality and Alzheimer's disease: An integrative review. Personal Disord. 2019 Jan;10(1):4-12. PubMed.
4. Huang AR, Strombotne KL, Horner EM, Lapham SJ. Adolescent Cognitive Aptitudes and Later-in-Life Alzheimer Disease and Related Disorders. JAMA Netw Open. 2018 Sep 7;1(5):e181726. PubMed.

External Citations

1. Project Talent

Further Reading

Papers

1. Balsis S, Carpenter BD, Storandt M. Personality change precedes clinical diagnosis of dementia of the Alzheimer type. J Gerontol B Psychol Sci Soc Sci. 2005 Mar;60(2):P98-P101. PubMed.
2. Robins Wahlin TB, Byrne GJ. Personality changes in Alzheimer's disease: a systematic review. Int J Geriatr Psychiatry. 2011 Oct;26(10):1019-29. PubMed.