Personality factors moderate the associations between apolipoprotein genotype and cognitive function as well as late onset Alzheimer disease

Examining the relationship between anxiety and regional brain volumes in the National Alzheimer's Coordinating Center uniform, imaging, and biomarker datasets

Anxiety has been associated with a greater risk of Alzheimer's disease (AD). Existing research has identified structural differences in regional brain tissue in participants with anxiety, but results have been inconsistent. We sought to determine the association between anxiety and regional brain volumes, and the moderation effect of APOE ε4. Using data from participants in the National Alzheimer's Coordinating Center (NACC) Uniform Data Set, with complete imaging (MRI) and biomarker data (n = 1533), multiple linear regression estimated the adjusted effect of anxiety on 30 structural MRI regions. The moderation effect of APOE ε4 on the relation between structural MRI regions and anxiety was assessed as was the moderation effect of cognitive status. False discovery rate was used to adjust for multiple comparisons. After controlling for intracranial volume, age, sex, years of education, race, Hispanic ethnicity, and cognitive status, seven MRI regions demonstrated lower volumes among participants with anxiety: total cerebrum gray matter volume, right hippocampus volume, hippocampal volume (total), right and left frontal lobe cortical gray matter volume, and right and total temporal lobe cortical gray matter volume. Findings suggest that anxiety is associated with significant atrophy in multiple brain regions, with corresponding ventricular enlargement. Future research should investigate if anxiety-related changes to brain morphology contribute to greater AD risk.

Loneliness and risk of all-cause, Alzheimer's, vascular, and frontotemporal dementia: a prospective study of 492,322 individuals over 15 years

OBJECTIVES

This study examined the association between loneliness and risk of incident all-cause dementia and whether the association extends to specific causes of dementia.

DESIGN

Longitudinal.

SETTING

Community.

PARTICIPANTS

Participants were from the UK Biobank (N = 492,322).

INTERVENTION

None.

MEASUREMENTS

Loneliness was measured with a standard item. The diagnosis of dementia was derived from health and death records, which included all-cause dementia and the specific diagnoses of Alzheimer's disease (AD), vascular dementia (VD), and frontotemporal dementia (FTD), over 15 years of follow-up.

RESULTS

Feeling lonely was associated with a nearly 60% increased risk of all-cause dementia (HR = 1.59, 95% CI = 1.51-1.65; n = 7,475 incident all-cause). In cause-specific analyses, loneliness was a stronger predictor of VD (HR = 1.82, 95% CI = 1.62-2.03; n = 1,691 incident VD) than AD (HR = 1.40, 95% CI = 1.28-1.53; n = 3135 incident AD) and was, surprisingly, a strong predictor of FTD (HR = 1.64, 95% CI = 1.22-2.20; n = 252 incident FTD). The associations were robust to sensitivity analyses and were attenuated but remained significant accounting for clinical (e.g. diabetes) and behavioral (e.g. physical activity) risk factors, depression, social isolation, and genetic risk. The association between loneliness and all-cause and AD risk was moderated by APOE ϵ4 risk status such that the increased risk was apparent in both groups but stronger among non-carriers than carriers of the risk allele.

CONCLUSION

Loneliness is associated with increased risk of multiple types of dementia.

CAG Repeats Within the Non-pathological Range in the HTT Gene Influence Personality Traits in Patients With Subjective Cognitive Decline: A 13-Year Follow-Up Study

OBJECTIVE

HTT is a gene containing a key region of CAG repeats. When expanded beyond 39 repeats, Huntington disease (HD) develops. HTT genes with <35 repeats are not associated with HD. The biological function of CAG repeat expansion below the non-pathological threshold is not well understood. In fact higher number of repeats in HTT confer advantageous changes in brain structure and general intelligence, but several studies focused on establishing the association between CAG expansions and susceptibility to psychiatric disturbances and to other neurodegenerative disease than HD. We hypothesized that HTT CAG repeat length below the pathological threshold might influence mood and personality traits in a longitudinal sample of individuals with Subjective Cognitive Decline.

METHODS

We included 54 patients with SCD. All patients underwent an extensive neuropsychological battery at baseline, APOE genotyping and analysis of HTT alleles. We used the Big Five Factors Questionnaire (BFFQ) and Hamilton Depression Rating Scale (HDRS), respectively, to assess personality traits of patients and depression at baseline. Patients who did not progress to Mild Cognitive Impairment (MCI) had at least 5-year follow-up time.

RESULTS

In the whole sample, CAG repeat number in the shorter HTT allele was inversely correlated with conscientiousness (Pearson = -0.364, p = 0.007). There was no correlation between HDRS and CAG repeats. During the follow-up, 14 patients [25.93% (95% C.I. = 14.24-37.61)] progressed to MCI (MCI⁺) and 40 [74.07% (95% C.I. = 62.39-85.76)] did not (MCI^-). When we performed the same analysis in the MCI⁺ group we found that: CAG repeat length on the shorter allele was inversely correlated with energy (Pearson = 0.639, p = 0.014) and conscientiousness (Pearson = -0.695, p = 0.006). CAG repeat length on the longer allele was inversely correlated with conscientiousness (Pearson = -0.901, p < 0.001) and directly correlated with emotional stability (Pearson = 0.639, p = 0.014). These associations were confirmed also by multivariate analysis. We found no correlations between BFFQ parameters and CAG repeats in the MCI^- group.

DISCUSSION

Personality traits and CAG repeat length in the intermediate range have been associated with progression of cognitive decline and neuropathological findings consistent with AD. We showed that CAG repeat lengths in the HTT gene within the non-pathological range influence personality traits.

Subjective Cognitive Decline: Is a Resilient Personality Protective Against Progression to Objective Cognitive Impairment? Findings from Two Community-Based Cohort Studies

BACKGROUND

Subjective cognitive decline (SCD) is related to personality functioning and risk of subsequent objective cognitive impairment.

OBJECTIVE

The aim of this study was to examine whether lower neuroticism and higher conscientiousness-resilient personality traits-protect against conversion from SCD to objective cognitive impairment in two longitudinal community-based cohorts.

METHODS

Data from the Health and Retirement Study (N = 1,741, Mean age = 68.64 years, Follow-up mean = 7.34 years) and the National Health and Aging Trends Survey (N = 258, Mean age = 79.34 years, Follow-up mean = 4.31 years) were analyzed using Cox regression analysis, controlling for sociodemographic covariates, symptoms of anxiety and depression, and apolipoprotein ɛ4.

RESULTS

The pooled results showed that lower neuroticism and higher conscientiousness were associated with decreased risk of conversion from SCD to objective cognitive impairment.

CONCLUSION

Among individuals with SCD, those with a resilient personality may have more cognitive and psychological reserve to maintain cognitive functioning and delay conversion to objective cognitive impairment. The findings further contribute to a better understanding of personality along the cognitive continuum: The observed effect sizes were smaller than those reported in cognitively normal individuals but larger than in individuals with mild cognitive impairment. Personality could provide useful information to identify individuals with SCD who may develop objective cognitive impairment-namely those who hold a vulnerable personality (higher neuroticism, lower conscientiousness).

The Relation Between Personality and Biomarkers in Sensitivity and Conversion to Alzheimer-Type Dementia

OBJECTIVES

The present study explored relationships among personality, Alzheimer's disease (AD) biomarkers, and dementia by addressing the following questions: (1) Does personality discriminate healthy aging and earliest detectable stage of AD? (2) Does personality predict conversion from healthy aging to early-stage AD? (3) Do AD biomarkers mediate any observed relationships between personality and dementia status/conversion?

METHODS

Both self- and informant ratings of personality were obtained in a large well-characterized longitudinal sample of cognitively normal older adults (N = 436) and individuals with early-stage dementia (N = 74). Biomarkers included amyloid imaging, hippocampal volume, cerebral spinal fluid (CSF) Aβ42, and CSF tau.

RESULTS

Higher neuroticism, lower conscientiousness, along with all four biomarkers strongly discriminated cognitively normal controls from early-stage AD individuals. The direct effects of neuroticism and conscientiousness were only mediated by hippocampal volume. Conscientiousness along with all biomarkers predicted conversion from healthy aging to early-stage AD; however, none of the biomarkers mediated the relationship between conscientiousness and conversion. Conscientiousness predicted conversion as strongly as the biomarkers, with the exception of hippocampal volume.

CONCLUSIONS

Conscientiousness and to a lesser extent neuroticism serve as important independent behavioral markers for AD risk.

Personality factors and cerebral glucose metabolism in community-dwelling older adults

Personality factors have been associated with Alzheimer's disease (AD) and dementia, but they have not been examined against markers of regional brain glucose metabolism (a primary measure of brain functioning) in older adults without clinically diagnosed cognitive impairment. The relationship between personality factors derived from the five-factor model and cerebral glucose metabolism determined using positron emission tomography (PET) with [18F]-2-fluoro-2-deoxy-D-glucose (18F-FDG-PET) was examined in a cohort of 237 non-demented, community-dwelling older adults aged 60-89 years (M ± SD = 73.76 ± 6.73). Higher neuroticism and lower scores on extraversion and conscientiousness were significantly associated with decreased glucose metabolism in brain regions typically affected by AD neuropathological processes, including the hippocampus and entorhinal cortex. Furthermore, while there were significant differences between apolipoprotein E (APOE) ε4 allele carriers and non-carriers on ¹⁸F-FDG-PET results in the neocortex and other brain regions (p < 0.05), there was no significant difference between carriers and non-carriers on personality factors and no significant interactions were found between APOE ε4 carriage and personality factors on brain glucose metabolism. In conclusion, we found significant relationships between personality factors and glucose metabolism in neural regions more susceptible to AD neuropathology in older adults without clinically significant cognitive impairment. These findings support the need for longitudinal research into the potential mechanisms underlying the relationship between personality and dementia risk, including measurement of change in other AD biomarkers (amyloid and tau imaging) and how they correspond to change in personality factors. Future research is also warranted to determine whether timely psychological interventions aimed at personality facets (specific aspects or characteristics of personality factors) can affect imaging or other biomarkers of AD resulting in delay or ideally preventing the onset of the cognitive impairment.

Personality and Incident Alzheimer's Disease: Theory, Evidence, and Future Directions

Personality, especially the dimensions of neuroticism and conscientiousness, has prospectively predicted the risk of incident Alzheimer's disease (AD). Such a relationship could be explained by personality and AD risk having a common cause such as a gene; by personality creating a predisposition for AD through health behavior or inflammation; by personality exerting a pathoplastic effect on the cognitive consequences of neuropathology; or by AD and personality change existing on a disease spectrum that begins up to decades before diagnosis. Using the 5-dimensional taxonomy of personality, the present review describes how these models might arise, the evidence for each, and how they might be distinguished from one another empirically. At present, the evidence is sparse but tends to suggest predisposition and/or pathoplastic relationships. Future studies using noninvasive assessment of neuropathology are needed to distinguish these 2 possibilities.

Sociodemographic, Medical, and Psychosocial Factors Associated With Supportive Care Needs in Adults Diagnosed With Uveal Melanoma

Importance

Understanding supportive care needs in patients with cancer is important for developing approaches that enhance quality of life and promote satisfaction with care.

Objective

To characterize the nature and frequency of sociodemographic, medical, and psychosocial factors associated with unmet needs in patients with uveal melanoma 1 week and 3 months after diagnosis.

Design, Setting, and Participants

This 3-month, prospective, longitudinal survey study was conducted at a university-based ophthalmology practice from June 1, 2007, to July 1, 2011. Data were analyzed in April 2017. Consecutive patients (n = 429) scheduled for diagnostic evaluation for an intraocular abnormality were assessed for eligibility. Participants were ineligible (n = 25) if they were younger than 18 years, had previous advanced cancer, or evidenced cognitive impairment. Of the patients who provided informed consent (n = 306), those subsequently diagnosed with uveal melanoma by an ophthalmologist (n = 107) were included in the analysis.

Main Outcomes and Measures

Unmet needs (ie, desire for help in psychological, physical, health information, communication, or social domains) were assessed using the Cancer Needs Questionnaire. Multivariable regression analyses determined factors associated with unmet need severity across 3 months.

Results

One hundred seven patients (58 [54%] men; mean [SD] age, 59.0 [12.8] years) completed the baseline assessment. At 1 week after diagnosis, nearly all patients (85 of 86 [99%]) expressed at least 1 unmet need, as did 68 of 79 (86%) 3 months later. The most frequently endorsed needs were in the health information and psychological domains. Patients' unmet needs declined significantly over 3 months (mean [SD] change, -10.0 [14.4]; 95% CI, -6.4 to -13.6; t = -5.6). Sociodemographic and medical characteristics were unrelated to unmet need severity. However, higher prediagnosis instrumental social support (b = -0.2; 95% CI, -0.3 to -0.1; z = -2.8) and lower neuroticism (b = 0.3; 95% CI, 0.1-0.5; z = 2.9) predicted lower unmet need severity 1 week after diagnosis. Having a smaller social network predicted lower unmet need severity 3 months after diagnosis (b < 0.1; 95% CI, <0.1 to <0.1; z = 2.4) as well as a decline in needs from diagnosis to 3 months later (b < 0.1; 95% CI, <0.1 to <0.1; z = 2.3).

Conclusions and Relevance

Within 1 week after diagnosis and 3 months later, most patients with uveal melanoma cited important health information and psychological needs. These findings suggest that prior to or at diagnosis, the severity of such needs and psychosocial factors that may be associated can be identified for proactive supportive intervention.

Lifespan Intellectual Factors, Genetic Susceptibility, and Cognitive Phenotypes in Aging: Implications for Interventions

Along with rapid global population aging, the age-related cognitive disorders such as mild cognitive impairment (MCI) and dementia have posed a serious threat to public health, health care system, and sustainable economic and societal development of all countries. In this narrative review, we seek to summarize the major epidemiological studies from the life-course perspective that investigate the influence of genetic susceptibility [e.g., apolipoprotein (APOE) ε4 allele] and intellectual or psychosocial factors (e.g., educational attainments and leisure activities) as well as their interactions on cognitive phenotypes in aging. Numerous population-based studies have suggested that early-life educational attainments and socioeconomic status, midlife work complexity and social engagements, late-life leisure activities (social, physical, and mentally-stimulating activities), certain personality traits (e.g., high neuroticism and low conscientiousness), and depression significantly affect late-life cognitive phenotypes. Furthermore, certain intellectual or psychosocial factors (e.g., leisure activities and depression) may interact with genetic susceptibility (e.g., APOE ε4 allele) to affect the phenotypes of cognitive aging such that risk or beneficial effects of these factors on cognitive function may vary by carrying the susceptibility genes. Current evidence from the randomized controlled trials that support the cognitive benefits of cognitive training among cognitive healthy older adults remains limited. The cognitive reserve hypothesis has been proposed to partly explain the beneficial effects of lifetime intellectual and psychosocial factors on late-life cognitive function. This implies that, from a life-course perspective, preventive intervention strategies targeting multiple modifiable intellectual and psychosocial factors could interfere with clinical expression of cognitive disorders in old age and delay the onset of dementia syndrome, and thus, may help achieve healthy brain aging.

Personality and Alzheimer's disease: An integrative review

The objective of this article is to review and integrate interrelated areas of research on personality and Alzheimer's disease (AD). Prospective studies indicate that individuals who score higher on conscientiousness (more responsible and self-disciplined) and lower on neuroticism (less anxious and vulnerable to stress) have a reduced risk of developing dementia, even in the presence of AD neuropathology. Personality is also related to measures of cognitive performance and cognitive decline, with effect sizes similar to those of other clinical, lifestyle, and behavioral risk factors. These associations are unlikely to be due to reverse causality: Long-term prospective data indicate that there are no changes in personality that are an early sign of the disease during the preclinical phase of AD. With the onset and progression of dementia, however, there are large changes in personality that are reported consistently by caregivers in retrospective studies and are consistent with the clinical criteria for the diagnosis of dementia. The review also discusses potential mechanisms of the observed associations and emphasizes the need for prospective studies to elucidate the interplay of personality traits with AD neuropathology (amyloid and tau biomarkers) in modulating the risk and timing of onset of clinical dementia. The article concludes with the implications of personality research for identifying those at greater risk of AD and the potential of personality-tailored interventions aimed at the prevention and treatment of AD. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Facets of Conscientiousness and risk of dementia

BACKGROUND

Multiple studies have found Conscientiousness to be protective against dementia. The purpose of this study is to identify which specific aspects, or facets, of Conscientiousness are most protective against cognitive impairment and whether these associations are moderated by demographic factors and/or genetic risk.

METHODS

Health and Retirement Study participants were selected for analysis if they completed the facets of Conscientiousness measure, scored in the range of normal cognitive functioning at the baseline personality assessment, and had at least one follow-up assessment of cognition over the up to 6-year follow-up (N = 11 181). Cox regression was used to test for risk of incident dementia and risk of incident cognitive impairment not dementia (CIND).

RESULTS

Over the follow-up, 278 participants developed dementia and 2186 participants developed CIND. The facet of responsibility had the strongest and most consistent association with dementia risk: every standard deviation increase in this facet was associated with a nearly 35% decreased risk of dementia; self-control and industriousness were also protective. Associations were generally similar when controlling for clinical, behavioral, and genetic risk factors. These three facets were also independent predictors of decreased risk of CIND.

CONCLUSIONS

The present research indicates that individuals who see themselves as responsible, able to control their behavior, and hard workers are less likely to develop CIND or dementia and that these associations persist after accounting for some common clinical, behavioral, and genetic risk factors.

Conscientiousness is Negatively Associated with Grey Matter Volume in Young APOE ɛ4-Carriers

The etiology of late onset Alzheimer's disease (LOAD) depends on multiple factors, among which the APOE ɛ4 allele is the most adverse genetic determinant and conscientiousness represents an influential personality trait. A potential association of both factors with brain structure in young adulthood may constitute a constellation that sets the course toward or against the subtle disease progression of LOAD that starts decades before clinical manifestation. Hence, in the present study, we examined the modulating effects of APOE ɛ4 on the relation between personality dimensions, including conscientiousness, and total grey matter volume (GMV) in young healthy adults using an a priori genotyping design. 105 participants completed an inventory assessing the Five Factor Model of Personality (NEO-FFI) and a structural MRI scan. Total GMV was estimated using both Freesurfer as well as VBM8. Across all participants, total GMV was positively associated with extraversion and negatively related to age. In APOE ɛ4-carriers- but not in APOE ɛ4-non-carriers- conscientiousness was negatively associated with total GMV. In line with the hypothesis of antagonistic pleiotropy of the APOE ɛ4 allele, this result suggests that young APOE ɛ4-carriers with increased total GMV may particularly benefit from cognitive advantages and thus have a lower need to engage in conscientious behavior. In this subset of young APOE ɛ4-carriers, the reduction in conscientiousness could then bring along adverse health behavior in the long run, potentiating the risk for LOAD. Hence, young APOE ɛ4-carriers with increased total GMV may be at a particularly high risk for LOAD.

Apolipoprotein E genotype does not moderate the associations of depressive symptoms, neuroticism and allostatic load with cognitive ability and cognitive aging in the Lothian Birth Cohort 1936

OBJECTIVES

In this replication-and-extension study, we tested whether depressive symptoms, neuroticism, and allostatic load (multisystem physiological dysregulation) were related to lower baseline cognitive ability and greater subsequent cognitive decline in older adults, and whether these relationships were moderated by the E4 allele of the apolipoprotein E (APOE) gene. We also tested whether allostatic load mediated the relationships between neuroticism and cognitive outcomes.

METHODS

We used data from the Lothian Birth Cohort 1936 (n at Waves 1-3: 1,028 [M age = 69.5 y]; 820 [M duration since Wave 1 = 2.98 y]; 659 [M duration since Wave 1 = 6.74 y]). We fitted latent growth curve models of general cognitive ability (modeled using five cognitive tests) with groups of APOE E4 non-carriers and carriers. In separate models, depressive symptoms, neuroticism, and allostatic load predicted baseline cognitive ability and subsequent cognitive decline. In addition, models tested whether allostatic load mediated relationships between neuroticism and cognitive outcomes.

RESULTS

Baseline cognitive ability had small-to-moderate negative associations with depressive symptoms (β range = -0.20 to -0.17), neuroticism (β range = -0.27 to -0.23), and allostatic load (β range = -0.11 to 0.09). Greater cognitive decline was linked to baseline allostatic load (β range = -0.98 to -0.83) and depressive symptoms (β range = -1.00 to -0.88). However, APOE E4 allele possession did not moderate the relationships of depressive symptoms, neuroticism and allostatic load with cognitive ability and cognitive decline. Additionally, the associations of neuroticism with cognitive ability and cognitive decline were not mediated through allostatic load.

CONCLUSIONS

Our results suggest that APOE E4 status does not moderate the relationships of depressive symptoms, neuroticism, and allostatic load with cognitive ability and cognitive decline in healthy older adults. The most notable positive finding in the current research was the strong association between allostatic load and cognitive decline.

Apolipoprotein E genotype impact on memory and attention in older persons: the moderating role of personality phenotype

OBJECTIVES

To determine if phenotypic personality traits modify the association of Apolipoprotein E (APOE) genotypes with different domains of cognitive function.

DESIGN

Cross-sectional.

METHODS

172 non-demented older adults were administered the NEO-Five Factor Inventory (NEO-FFI), a battery of neuropsychological tests assessing memory, attention, executive function, language, and visuospatial ability, and underwent APOE genotyping. Multivariate (multiple-dependent variable) regression models predicting cognitive domains tested APOE interactions with personality traits, adjusting for age, sex, and education.

RESULTS

The APOE ε4 allele showed small to modest main effects on memory and executive function (1/3 SD deficits for carriers, p < .05), with ε2 status evidencing minimal and non-significant benefit. Neuroticism interacted with both ε2 and ε4 alleles in associations with attention scores (p = .001), with ε2 benefits and ε4 deficits being marked at high Neuroticism (Mean [M] covariate-adjusted Z-score = .39 for ε2, -.47 for ε4). The association of ε4 with memory was moderated by Conscientiousness (p < .001), such that ε4 memory deficits were apparent at low Conscientiousness (M = -.56), but absent at high levels of Conscientiousness. Weaker patterns (p < .05) also suggested ε4-related detriments in executive function only at lower Conscientiousness, and ε2 memory benefits only at higher Openness.

CONCLUSIONS

Conscientiousness and Neuroticism moderate APOE associations with memory and executive function. As such, they may be useful phenotypic markers in refining the prognostic significance of this polymorphism. Effect-modifying personality traits also provide clues about behavioral and psychological factors that influence the cognitive impact of APOE. Copyright © 2017 John Wiley & Sons, Ltd.

Moderating risk of Alzheimer's disease through the use of anxiolytic agents

OBJECTIVES

Anxiety diagnoses occur in 17.1% in people age 65 years and older. Individuals with anxiety may be at a higher risk of the development of probable Alzheimer's disease (AD). Previous literature has suggested that anxiolytic medications may exacerbate the risk of AD development. This study explored anxiolytic medication as a potential moderator of AD risk in older adults.

METHODS

A secondary data analysis of the National Alzheimer's Coordinating Center Uniform Data Set was undertaken, analyzing observations from 12,083 participants with normal cognition at the first visit. Survival analysis was utilized to examine if anxiolytic medication use by those with anxiety and/or APOE ɛ4 moderates the hazard of AD and/or MCI development.

RESULTS

The hazard of probable AD (HR = 3.50, [2.77 - 4.44], p < .0001) or MCI (HR = 2.13, [1.85-2.44], p < .0001) development was statistically significant for those with anxiety. This hazard was no longer statistically significant when specific anxiolytics were used. ɛ4 carriers experienced a statistically significant hazard of AD (HR = 1.92, [1.52-2.41], p < .001) and MCI (HR = 1.17, [1.04-1.32], p < .05) development. This effect was moderated by the use of anxiolytics.

DISCUSSION

The results of this study suggest that anxiolytics may moderate the effect of anxiety on MCI and AD development, specifically indicating a neutralized hazard for those with ɛ4 carriers with anxiety. Copyright © 2016 John Wiley & Sons, Ltd.

Relations between personality changes and cerebrospinal fluid biomarkers of Alzheimer's disease pathology

Specific changes in personality profiles may represent early non-cognitive symptoms of Alzheimer's disease (AD). Evaluating the subject's personality changes may add significant clinical information, as well as help to better understand the interaction between personality change, cognitive decline, and cerebral pathology. With this study we aimed to describe the relationship between personality changes and cerebrospinal fluid (CSF) markers of AD pathology at early clinical stages of the disease. One hundred and ten subjects, of whom 66 cognitively impaired patients (57 with mild cognitive impairment (MCI), and 9 with mild dementia) and 44 healthy controls, had neuropsychological examination as well as lumbar puncture to determine concentrations of CSF biomarkers of AD pathology (amyloid beta_1-42 (Aβ_1-42), phosphorylated tau (ptau-181), and total-tau (tau)). The Revised NEO Personality Inventory (NEO-PI-R) was administered twice, once to evaluate subjects' current personality and once to assess personality traits retrospectively 5 years before evaluation. Subjects with an AD CSF biomarker profile showed significant increase in neuroticism and decrease in conscientiousness over time as compared to non-AD CSF biomarker group. In regression analysis controlling for global cognition as measured by the MMSE score, increasing neuroticism and decreasing extraversion, openness to experience and conscientiousness were associated with lower Aβ_1-42 concentrations but not with tau and ptau-181 concentrations. Our findings suggest that early and specific changes in personality are associated with cerebral AD pathology. Concentrations of CSF biomarkers, additionally to severity of the cognitive impairment, significantly contribute in predicting specific personality changes.

Interaction between personality traits and cerebrospinal fluid biomarkers of Alzheimer's disease pathology modulates cognitive performance

Background

During adulthood, personality characteristics may contribute to the individual capacity to compensate the impact of developing cerebral Alzheimer’s disease (AD) pathology on cognitive impairment in later life. In this study we aimed to investigate whether and how premorbid personality traits interact with cerebrospinal fluid (CSF) markers of AD pathology to predict cognitive performance in subjects with mild cognitive impairment or mild AD dementia and in participants with normal cognition.

Methods

One hundred and ten subjects, of whom 66 were patients with mild cognitive impairment or mild AD dementia and 44 were healthy controls, had a comprehensive medical and neuropsychological examination as well as lumbar puncture to measure CSF biomarkers of AD pathology (amyloid beta_1–42, phosphorylated tau and total-tau). Participants’ proxies completed the Revised NEO Personality Inventory, Form R to retrospectively assess subjects’ premorbid personality.

Results

In hierarchical multivariate regression analyses, including age, gender, education, APOEε4 status and cognitive level, premorbid neuroticism, conscientiousness and agreeableness modulated the effect of CSF biomarkers on cognitive performance. Low premorbid openness independently predicted lower levels of cognitive functioning after controlling for biomarker concentrations.

Conclusion

Our findings suggest that specific premorbid personality traits are associated with cerebral AD pathology and modulate its impact on cognitive performance. Considering personality characteristics may help to appraise a person’s cognitive reserve and the risk of cognitive decline in later life.

Apolipoprotein E and Clusterin can magnify effects of personality vulnerability on declarative memory performance in non-demented older adults

OBJECTIVES

Recent research has linked psychological (personality) factors and specific genetic risk polymorphisms to performance on neurocognitive phenotypes. We examined whether episodic or semantic memory performance is associated with (a) three personality traits (i.e. neuroticism, extraversion, and openness to experience), (b) two neurodegenerative-related polymorphisms (i.e. Apolipoprotein E (APOE; rs7412; rs429358), Clusterin (CLU; rs11136000)), and (c) cross-domain risk interactions (magnification effects).

METHODS

Linear growth models were examined to test independent associations between personality traits and declarative memory performance, and potential interaction effects with APOE and CLU genetic risk. Normal older adults (n = 282) with personality and genetic data from the Victoria Longitudinal Study were included at baseline and for up to 14 years of follow-up.

RESULTS

First, we observed that higher openness to experience levels were associated with better episodic and semantic memory. Second, three significant gene × personality interactions were associated with poorer memory performance at baseline. These synergistic effects are: (a) APOE allelic risk (ε4+) carriers with lower openness to experience levels, (b) CLU (no risk: T/T) homozygotes with higher extraversion levels, and (c) CLU (no risk: T/T) homozygotes with lower neuroticism levels.

CONCLUSIONS

Specific neurodegenerative-related genetic polymorphisms (i.e. APOE and CLU) moderate and magnify the risk contributed by selected personality trait levels (i.e. openness to experience, extraversion) on declarative memory performance in non-demented aging. Future research could target interactions of other personality traits and genetic polymorphisms in different clinical populations to predict other neurocognitive deficits or transitions to cognitive impairment and dementia.

Neuroticism scores increase with late-life cognitive decline

OBJECTIVE

Neuroticism has been reported as both a risk factor for cognitive decline and a characteristic that increases in parallel with the development of mild cognitive impairment (MCI) and dementia. However, the evidence for these associations is inconclusive, and whether effects are stronger for particular cognitive domains is unknown. We investigated these issues and determined if associations differ among different components of neuroticism.

METHODS

A neuroticism scale (NEO-FFI) and neuropsychological test battery were administered to 603 older adults without dementia, with 493 of these reassessed two years later. Diagnoses of MCI and dementia (at follow-up) were made, and global cognition and performance in six cognitive domains quantified. The neuroticism components were negative affect, self-reproach, and proneness to psychological distress.

RESULTS

For the whole sample, neuroticism scores remained stable between baseline (15.3 ± 7.0) and follow-up (15.5 ± 7.0), as did all neuroticism component scores. However, there were declines in global cognition (p < 0.05) and particular cognitive domains (p < 0.001). Higher neuroticism was associated with poorer cognition cross-sectionally (p < 0.01), but did not predict cognitive decline. For 43 participants who developed incident MCI or dementia, there were increases in neuroticism (15.3 ± 6.4 to 17.1 ± 8.3, p < 0.05) and negative affect (p < 0.05). Declines in all cognitive measures except executive function were associated with increases in neuroticism and component scores (p < 0.05).

CONCLUSIONS

Late-life cognitive decline is associated with an increase in neuroticism scores. However, associations vary between different cognitive domains and components of neuroticism. An increase in neuroticism or negative affect scores may be a sign of MCI or dementia.

Subjective Cognitive Complaints, Personality and Brain Amyloid-beta in Cognitively Normal Older Adults

OBJECTIVE

Subjective cognitive complaints in otherwise normal aging are common but may be associated with preclinical Alzheimer disease in some individuals. Little is known about who is mostly likely to show associations between cognitive complaints and preclinical Alzheimer pathology. We sought to demonstrate associations between subjective complaints and brain amyloid-β in cognitively normal older adults; and to explore personality factors as potential moderators of this association.

DESIGN

Cross-sectional observational study.

SETTING

Clinical neuroimaging research center.

PARTICIPANTS

Community volunteer sample of 92 healthy older adults, screened for normal cognition with comprehensive neuropsychological evaluation.

MEASUREMENTS

Subjective cognitive self-report measures included the Memory Functioning Questionnaire (MFQ), Cognitive Failures Questionnaire, and the Subjective Cognitive Complaint Scale. Personality was measured with the NEO Five Factor Inventory. Brain amyloid-β deposition was assessed with Pittsburgh compound B (PiB)-PET imaging.

RESULTS

One of three cognitive complaint measures, the MFQ, was associated with global PiB retention (standardized beta = -0.230, p = 0.046, adjusting for age, sex and depressive symptoms). Neuroticism moderated this association such that only high neuroticism individuals showed the predicted pattern of high complaint-high amyloid-β association.

CONCLUSION

Evidence for association between subjective cognition and brain amyloid-β deposition in healthy older adults is demonstrable but measure-specific. Neuroticism may moderate the MFQ-amyloid-β association such that it is observed in the context of higher trait neuroticism. Subjective cognitive complaints and neuroticism may reflect a common susceptibility toward psychological distress and negative affect, which are in turn risk factors for cognitive decline in aging and incident Alzheimer disease.

Role of depression in predicting time to conversion to mild cognitive impairment

OBJECTIVE

To establish whether, in a cohort with normal cognition, severity of depressive symptoms at baseline was related to the time taken for conversion to mild cognitive impairment (MCI) and whether this interacted with other potential risk factors, including APOE ε4 status and demographic and cognitive variables.

METHODS

In a population-based cohort study, 126 cognitively normal subjects were assessed for depressive symptoms at baseline using the Geriatric Depression Scale (GDS) and were then followed over 20 years with regular cognitive assessments. The interval-censored accelerated failure time model was used to establish whether GDS and other factors, including APOE ε4 status, predicted the median time to development of MCI.

RESULTS

Fifty subjects developed MCI. In APOE ε4 noncarriers, the degree of depressive symptoms at baseline predicted the time to development of MCI: An increase in GDS of 1 standard deviation (3.85) was associated with shortening of the median time to conversion to MCI by 25.4% (p = 0.0024, z = -5.6). This relationship remained statistically significant after controlling for cognitive and other confounding variables. The relationship was not significant in APOE ε4 carriers.

CONCLUSION

Depressive symptoms (measured by GDS) predict time to conversion to MCI in cognitively normal people who do not carry the APOE ε4 allele. This may explain conflicting results of previous studies where APOE ε4 status was not taken into account when exploring the relationship between depression and MCI. It may also have a clinical application in helping to identify people at greater risk of developing MCI.

Common genetic variation of the APOE gene and personality

BACKGROUND

A recent study yielded first evidence that personality plays an important role in explaining the influence of a prominent APOE polymorphism on cognitive decline and Alzheimer's disease (AD) in elderly humans. Adding to this, two earlier studies examined this polymorphism in the context of individual differences in temperament traits in young humans with mixed results. In general, research linking the prominent APOE ϵ2, ϵ3 and ϵ4 variants and human personality is of special interest, because an influence of this gene and its prominent polymorphism on personality in young adulthood could be of diagnostic value to predict AD and its development in later years.

RESULTS

In the present study N = 531 participants provided buccal swabs and filled in a self-report inventory measuring the Five Factor Model of Personality. No association between common genetic variations of the APOE gene (in detail the genotypes ϵ3/ϵ3, ϵ2/ϵ3 and ϵ3/ϵ4) and personality could be observed. The remaining genotypes, including the high risk constellation ϵ4/ϵ4 for AD, were too seldom to be tested.

CONCLUSIONS

In sum, the present study yielded no evidence for a direct link between common genetic variants of the APOE gene and personality in young adulthood.