Personality changes do not presage dementia, at least when examined through the lens of self-report, a large retrospective study has determined.
Dementia patients do show personality characteristics that are different from those of their cognitively normal peers, wrote Antonio Terracciano, PhD (JAMA Psychiatry. 2017 Sep 20. doi: 10.1001/jamapsychiatry.2017.2816). Notably, they tend to be more neurotic and less conscientious, he noted. But among more than 2,000 older adults with up to 36 years of data, no temporal associations were found between these traits and the onset of cognitive difficulty, even within a few years of the onset of dementia symptoms.
“From a clinical perspective, these findings suggest that tracking change in self-rated personality as an early indicator of dementia is unlikely to be fruitful, while a single assessment provides reliable information on the personality traits that increase resilience [e.g., conscientiousness] or vulnerability [e.g., neuroticism] to clinical dementia,” wrote Dr. Terracciano of Florida State University, Tallahassee, and his coauthors.
However, the authors noted, it’s possible that self-reported personality may not be as good a marker of dementia-related personality change as informant report.
“Self-rated personality provides participants’ perspectives of themselves. … Individuals with AD could be anosognosic to change in their psychological trains and functioning. Self-reported personality might remain stable and reflect premorbid functioning more than current traits,” the researchers wrote.
The study tracked 2,046 community-living older adults who were part of the Baltimore Longitudinal Study of Aging, which began in 1958. Healthy individuals of different ages are continuously enrolled in the study and assessed with regular follow-up visits. These visits include cognitive and neuropsychiatric assessments, from which data for this study were extracted. The mean follow-up time was about 12 years, but some subjects had up to 36 years. From 1980 to 2016, the group completed more than 8,000 assessments and accumulated 24,569 person/years of follow-up.
Dr. Terracciano examined the cohort’s Revised NEO Personality Inventory results, a 240-item questionnaire that assesses 30 facets of personality in the dimensions of neuroticism, extraversion, openness, agreeableness, and conscientiousness. Cognitive decline was assessed by results on the Clinical Dementia Rating Scale and the older Dementia Questionnaire.
At the end of the follow-up period, 104 subjects (5%) had developed mild cognitive impairment, and 255 (12.5%) all-cause dementia; of those, 194 (9.5%) were later diagnosed with Alzheimer’s disease. In an unadjusted analysis, the authors found that the group that eventually developed AD scored higher on neuroticism, and lower on extraversion, openness, and conscientiousness than did the nonaffected subjects.
Over time, the authors found some changes in the reference group, including small declines in neuroticism and extraversion, and small increases in agreeableness and conscientiousness. However, when they looked at the trajectory of change, they found no significant differences in the rate of any change, compared with the AD group – although that group continued to display changes in its baseline difference of neuroticism and conscientiousness.
“Although the trajectories were similar, there were significant ... differences on the intercept,” they wrote. “The AD cohort scored higher on neuroticism and lower on conscientiousness and extraversion than the nonimpaired group.”
The team ran several temporal analyses on the data, and none found any significant temporal association with accelerated personality change in the AD group, the MCI group, or the all-cause dementia groups compared with the reference group, with one exception: Subjects with MCI showed a steeper decline in openness than did nonaffected subjects.
Those results were consistent even when they examined the two assessments performed just before the onset of cognitive symptoms (a mean of 6 and 3 years). “Consistent with the results and the broader literature, the AD group scored higher on neuroticism and lower on conscientiousness. Contrary to expectations, the AD group did not increase in neuroticism and decline in conscientiousness.”
The findings may shed some light on the chicken-or-egg question of personality change and dementia, they suggested.
“This research has relevance to the question of reverse causality for the association between personality and risk of incident AD. That is, if personality changed in response to increasing neuropathology in the brain in the preclinical phase, the association between personality and AD could have been due to the disease process rather than personality as an independent risk factor. We did not, however, find any evidence that neuroticism and conscientiousness changed significantly as the onset of disease approached. Thus, rather than an effect of AD neuropathology, these traits appear to confer risk for the development of the disease.”
The Baltimore Longitudinal Study of Aging is supported by the National Institutes of Health. Neither Dr. Terracciano nor his colleagues had financial disclosures.
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