Personality and risk of Alzheimer's disease: new data and meta-analysis

High-frequency assessment of mood, personality, and cognition in healthy younger, healthy older and adults with cognitive impairment

Increased variability in cognitive scores, mood or personality traits can be indicative of underlying neurological disorders. Whether variability in cognition is due to changes in mood or personality is unknown. A total of 66 younger adults, 51 healthy older adults and 38 participants with cognitive impairment completed 21 daily sessions of attention, working memory, mood, and personality assessment. Group differences in mean performance and variability were examined using Bayesian mixed effects location scale models. Variability in attention decreased from younger to older adults and then increased again in cognitive impairment. Younger adults were more variable in agreeableness, openness and conscientiousness compared to older adults. The clinically impaired group differed from the healthy older adults in terms of variability on attention, openness, and conscientiousness. Healthy aging results in greater stability in personality traits over short intervals yet this stability is not redundant with increased stability in cognitive scores.

Does personality affect the cognitive decline in aging? A systematic review

Cognitive decline is a natural consequence of aging, but several genetic, environmental, and psychological factors can influence its trajectories. Among the most enduring factors, the Big Five personality traits - defined as relatively stable tendencies to think, behave, and react to the environment - can influence both directly (e.g., by physiological correlates) and indirectly (e.g., healthy or risky behaviors) the risk of developing dementia and mild cognitive impairment (MCI) - a preclinical form of cognitive decline. Despite the great amount of studies focusing on the relationship between personality and cognitive decline, an updated systematic synthesis of the results including a broader range of study designs is still lacking. This systematic review aims to summarize the findings of studies investigating: (i) differences in personality traits between groups of healthy individuals and those with MCI, (ii) the impact of personality traits on the risk for both MCI and dementia, and (iii) changes in personality traits among individuals progressing from normal cognition to MCI. Neuroticism emerged as a significant risk factor for MCI and dementia; Conscientiousness and Openness appear to offer protection against dementia and moderate cognitive decline. Overall, these findings suggest a pivotal role of personality structure in shaping cognitive outcomes on the long run.

Psychosocial experiences are associated with human brain mitochondrial biology

Psychosocial experiences affect brain health and aging trajectories, but the molecular pathways underlying these associations remain unclear. Normal brain function relies on energy transformation by mitochondria oxidative phosphorylation (OxPhos). Two main lines of evidence position mitochondria both as targets and drivers of psychosocial experiences. On the one hand, chronic stress exposure and mood states may alter multiple aspects of mitochondrial biology; on the other hand, functional variations in mitochondrial OxPhos capacity may alter social behavior, stress reactivity, and mood. But are psychosocial exposures and subjective experiences linked to mitochondrial biology in the human brain? By combining longitudinal antemortem assessments of psychosocial factors with postmortem brain (dorsolateral prefrontal cortex) proteomics in older adults, we find that higher well-being is linked to greater abundance of the mitochondrial OxPhos machinery, whereas higher negative mood is linked to lower OxPhos protein content. Combined, positive and negative psychosocial factors explained 18 to 25% of the variance in the abundance of OxPhos complex I, the primary biochemical entry point that energizes brain mitochondria. Moreover, interrogating mitochondrial psychobiological associations in specific neuronal and nonneuronal brain cells with single-nucleus RNA sequencing (RNA-seq) revealed strong cell-type-specific associations for positive psychosocial experiences and mitochondria in glia but opposite associations in neurons. As a result, these "mind-mitochondria" associations were masked in bulk RNA-seq, highlighting the likely underestimation of true psychobiological effect sizes in bulk brain tissues. Thus, self-reported psychosocial experiences are linked to human brain mitochondrial phenotypes.

Personality nuances and risk of dementia: Evidence from two longitudinal studies

Personality traits are broad constructs composed of nuances, operationalized by personality items, that can provide a more granular understanding of personality associations with health outcomes. This study examined the associations between personality nuances and incident dementia and evaluated whether nuances associations replicate across two samples. Health and Retirement Study (HRS, N = 11,400) participants were assessed in 2006/2008, and the English Longitudinal Study of Ageing (ELSA, N = 7453) participants were assessed in 2010/2011 on personality and covariates. Dementia incidence was tracked for 14 years in the HRS and 8 years in ELSA. In both HRS and ELSA, higher neuroticism domain and nuances (particularly nervous and worry) were related to a higher risk of incident dementia, whereas higher conscientiousness domain and nuances (particularly responsibility and organization) were associated with a lower risk of dementia. To a lesser extent, higher extraversion (active), openness (broad-minded, curious, and imaginative), and agreeableness (helpful, warm, caring, and sympathetic) nuances were associated with a lower risk of dementia, with replicable effects across the two samples. A poly-nuance score, aggregating the effects of personality items, was associated with an increased risk of incident dementia in the HRS and ELSA, with effect sizes slightly stronger than those of the personality domains. Clinical, behavioral, psychological, and genetic covariates partially accounted for these associations. The present study provides novel and replicable evidence for specific personality characteristics associated with the risk of incident dementia.

Lifestyle and psychosocial associations with cognition at the cusp of midlife using twins and siblings

INTRODUCTION

This study investigates the relationship between cognitive functioning and 59 modifiable and intrinsic factors at the cusp of midlife.

METHODS

We analyzed data from 1221 participants in the Colorado Adoption/Twin Study of Lifespan behavioral development and cognitive aging (CATSLife; Mage = 33.20, %Female = 52.74). We assessed the impact of 59 factors on cognitive functioning using regularized regression and co-twin control models, controlling for earlier-life cognitive functioning and gray matter volume.

RESULTS

Eight robust factors were identified, including education attainment, cognitive complexity, purpose-in-life, and smoking status. Twins reporting higher levels of cognitive complexity and purpose-in-life showed better cognitive performance than their cotwin, while smoking was negatively associated. Using meta-analytically derived effect size threshold, we additionally identified that twins experiencing more financial difficulty tend to perform less well compared with their cotwin.

DISCUSSION

The findings highlight the early midlife link between cognitive functioning and lifestyle/psychological factors, beyond prior cognitive performance, brain status, genetic and familial confounders. Our results further highlight the potential of established adulthood as a crucial window for dementia prevention interventions targeting lifestyle and psychosocial factors.

Highlights

Cog complexity(+), purpose-in-life(+) were associated with cognition in early midlife.Smoking(-) was also associated with cognition in early midlife.Results were consistent controlling for genetic and environmental confounds.Association between EA and cognition might be mostly genetic and familial confounded.

Exploring the retrospective and prospective associations between the big five personality traits and clinical diagnosis of angina in middle-aged and older adults

OBJECTIVE

The goal of the present research was to test the retrospective and prospective associations between the Big Five personality traits and clinical diagnosis of angina while controlling for demographic characteristics.

METHODS

Data from middle-aged and older adults from a cohort study Understanding Society: the UK Household Longitudinal Study (UKHLS) were extracted and analyzed using binary logistic regressions (N = 10,124 for the retrospective study and N = 5485 for the prospective study). Personality was measured using a self-report 15-item version of the Big Five inventory between 2011 and 2012. Angina was measured by a self-report clinical diagnosis history question in each wave from until 2019. Covariates in our models included age, sex, income (monthly), education, and marital status.

RESULTS

Neuroticism was positively related to the likelihood of clinical angina diagnosis in both the retrospective (OR = 1.22, 95% C.I. [1.11, 1.34]) and the prospective (OR = 1.52, 95% C.I. [1.19, 1.94]) study whereas Extraversion had a positive association with odds of angina (OR = 1.52, 95% C.I. [1.17, 1.97]) in the prospective study only. The negative association between Openness and clinical angina diagnosis in the cross-sectional analysis is borderline significant (OR = 0.91, p = 0.048, 95% C.I. [0.83, 1.00]).

CONCLUSION

Our research indicated that personality traits are associated with the risk of angina. These findings emphasize the importance of considering personality traits in understanding the etiology of angina and potentially informing personalized prevention and intervention strategies.

Neuroticism polygenic risk predicts conversion from mild cognitive impairment to Alzheimer's disease by impairing inferior parietal surface area

The high prevalence of conversion from amnestic mild cognitive impairment (aMCI) to Alzheimer's disease (AD) makes early prevention of AD extremely critical. Neuroticism, a heritable personality trait associated with mental health, has been considered a risk factor for conversion from aMCI to AD. However, whether the neuroticism genetic risk could predict the conversion of aMCI and its underlying neural mechanisms is unclear. Neuroticism polygenic risk score (N-PRS) was calculated in 278 aMCI patients with qualified genomic and neuroimaging data from ADNI. After 1-year follow-up, N-PRS in patients of aMCI-converted group was significantly greater than those in aMCI-stable group. Logistic and Cox survival regression revealed that N-PRS could significantly predict the early-stage conversion risk from aMCI to AD. These results were well replicated in an internal dataset and an independent external dataset of 933 aMCI patients from the UK Biobank. One sample Mendelian randomization analyses confirmed a potentially causal association from higher N-PRS to lower inferior parietal surface area to higher conversion risk of aMCI patients. These analyses indicated that neuroticism genetic risk may increase the conversion risk from aMCI to AD by impairing the inferior parietal structure.

The concept of resilience to Alzheimer's Disease: current definitions and cellular and molecular mechanisms

Some individuals are able to maintain their cognitive abilities despite the presence of significant Alzheimer's Disease (AD) neuropathological changes. This discrepancy between cognition and pathology has been labeled as resilience and has evolved into a widely debated concept. External factors such as cognitive stimulation are associated with resilience to AD, but the exact cellular and molecular underpinnings are not completely understood. In this review, we discuss the current definitions used in the field, highlight the translational approaches used to investigate resilience to AD and summarize the underlying cellular and molecular substrates of resilience that have been derived from human and animal studies, which have received more and more attention in the last few years. From these studies the picture emerges that resilient individuals are different from AD patients in terms of specific pathological species and their cellular reaction to AD pathology, which possibly helps to maintain cognition up to a certain tipping point. Studying these rare resilient individuals can be of great importance as it could pave the way to novel therapeutic avenues for AD.

Personality and cognitive errors in the Healthy Aging in Neighborhoods of Diversity across the Life Span study

This study examines the association between personality and cognitive errors in the Healthy Aging in Neighborhoods of Diversity across the Life Span study, a sample diverse across race (Black, White) and SES (above, below 125% of the federal poverty line). Participants (N=1,062) completed a comprehensive personality questionnaire and were administered a brief mental status screener of cognitive errors. Higher neuroticism was associated with more cognitive errors, whereas higher openness and conscientiousness were associated with fewer errors. These associations were independent of age, sex, race, poverty status, and education and were generally not moderated by these factors. These findings support the associations between personality and cognition across race and SES.

The Role of Catecholamines in the Pathogenesis of Diseases and the Modified Electrodes for Electrochemical Detection of Catecholamines: A Review

Catecholamines (CAs), which include adrenaline, noradrenaline, and dopamine, are neurotransmitters and hormones that critically regulate the cardiovascular system, metabolism, and stress response in the human body. The abnormal levels of these molecules can lead to the development of various diseases, including pheochromocytoma and paragangliomas, Alzheimer's disease, and Takotsubo cardiomyopathy. Due to their low cost, high sensitivity, flexible detection strategies, ease of integration, and miniaturization, electrochemical techniques have been extensively employed in the detection of CAs, surpassing traditional analytical methods. Electrochemical detection of CAs in real samples is challenging due to the tendency of poisoning electrode. Chemically modified electrodes have been widely used to solve the problems of poor sensitivity and selectivity faced by bare electrodes. There are a few articles that provide an overview of electrochemical detection and efficient enrichment of CAs, but there is a dearth of updates on the role of CAs in the pathogenesis of diseases. Additionally, there is still a lack of systematic synthesis with a focus on modified electrodes for electrochemical detection. Thus, this review provides a summary of the recent clinical pathogenesis of CAs and the modified electrodes for electrochemical detection of CAs published between 2017 and 2022. Moreover, challenges and future perspectives are also highlighted. This work is expected to provide useful guidance to researchers entering this interdisciplinary field, promoting further development of CAs pathogenesis, and developing more novel chemically modified electrodes for the detection of CAs.

Associations between personality and psychological characteristics and cognitive outcomes among older adults

Prior research has shown that some personality traits are associated with cognitive outcomes and may confirm risk or protection against cognitive decline. The present study expands on previous work to examine the association between a more comprehensive set of psychological characteristics and cognitive performance in a diverse cohort of older adults. We also examine whether controlling for brain atrophy influences the association between psychological characteristics and cognitive function. A total of 157 older adults completed a battery of psychological questionnaires (Openness to Experience, Conscientiousness, Agreeableness, Neuroticism, Extraversion, positive affect, negative affect-sadness, negative affect-anger, sense of purpose, loneliness, grit, and self-efficacy). Cognitive outcomes were measured across multiple domains: episodic memory, semantic memory, executive function, and spatial ability. Baseline brain (MRI) variables included gray matter, hippocampus, and total white matter hyperintensity volume. Parallel process, multilevel models yielded intercept (individual cognitive domain scores) and linear slope (global cognitive change) random effects for the cognitive outcomes. Positive affect (β = 0.013, SE = 0.005, p = .004) and Openness (β = 0.018, SE = 0.007, p = .009) were associated with less cognitive change, independent of baseline brain variables and covariates. Greater sadness predicted more cognitive decline when controlling for covariates, but not brain atrophy. A variety of psychological characteristics were associated with the cross-sectional measures of cognition. This study highlights the important impact of positive and negative affect on reducing or enhancing the risk of longitudinal cognitive decline. Such findings are especially important, given the available efficacious interventions that can improve affect. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Personality predictors of dementia diagnosis and neuropathological burden: An individual participant data meta-analysis

INTRODUCTION

The extent to which the Big Five personality traits and subjective well-being (SWB) are discriminatory predictors of clinical manifestation of dementia versus dementia-related neuropathology is unclear.

METHODS

Using data from eight independent studies (Ntotal = 44,531; Ndementia = 1703; baseline Mage = 49 to 81 years, 26 to 61% female; Mfollow-up range = 3.53 to 21.00 years), Bayesian multilevel models tested whether personality traits and SWB differentially predicted neuropsychological and neuropathological characteristics of dementia.

RESULTS

Synthesized and individual study results indicate that high neuroticism and negative affect and low conscientiousness, extraversion, and positive affect were associated with increased risk of long-term dementia diagnosis. There were no consistent associations with neuropathology.

DISCUSSION

This multistudy project provides robust, conceptually replicated and extended evidence that psychosocial factors are strong predictors of dementia diagnosis but not consistently associated with neuropathology at autopsy.

HIGHLIGHTS

N(+), C(-), E(-), PA(-), and NA(+) were associated with incident diagnosis. Results were consistent despite self-report versus clinical diagnosis of dementia. Psychological factors were not associated with neuropathology at autopsy. Individuals with higher conscientiousness and no diagnosis had less neuropathology. High C individuals may withstand neuropathology for longer before death.

Does social connection mediate the association between neuroticism and cognition? Cross-sectional analysis of the Canadian Longitudinal Study on Aging

OBJECTIVES

This study tested the association between neuroticism and six cognitive measures, and examined the potential mediating roles of social connection (social isolation and loneliness) among middle-aged and older adults.

METHODS

This cross-sectional study was a secondary analysis of the Canadian Longitudinal Study on Aging (CLSA) Comprehensive Cohort, a sample of Canadians aged 45-85 years at baseline. Respondents with data collected at the first follow-up, between 2015 and 2018, were included (n = 27,765). Structural equation modelling was used to assess the association between neuroticism and six cognitive measures (Rey Auditory Verbal Learning Test immediate recall and delayed recall, Animal Fluency Test, Mental Alternation Test, Controlled Oral Word Association Test and Stroop Test interference ratio), with direct and indirect effects (through social isolation and loneliness). All analyses were stratified by sex, including females (n = 14,133) and males (n = 13,632).

RESULTS

In unadjusted models, there was evidence of associations between neuroticism and all cognitive measures, except the Stroop Test interference ratio, suggesting higher neuroticism was associated with lower scores on memory and executive function tests. In the models of these other five outcomes, there was consistent evidence of indirect effects (through social isolation and loneliness) and, in some cases, direct effects. The results are discussed in context with limitations, including the use of cross-sectional design and alternative hypotheses to explain the association between personality and cognition.

CONCLUSION

Among middle-aged and older adults, for both males and females, the findings suggest that the association between neuroticism and cognitive outcomes may be mediated by aspects of social connection.

Revised Temperament and Character Inventory factors predict neuropsychiatric symptoms and aging-related cognitive decline across 25 years

Introduction

Personality traits and neuropsychiatric symptoms such as neuroticism and depression share genetic overlap and have both been identified as risks factors for development of aging-related neurocognitive decline and Alzheimer's disease (AD). This study aimed to examine revised personality factors derived from the Temperament and Character Inventory, previously shown to be associated with psychiatric disorders, as predictors of neuropsychiatric, cognitive, and brain trajectories of participants from a population-based aging study.

Methods

Mixed-effect linear regression analyses were conducted on data for the full sample (Nmax = 1,286), and a healthy subsample not converting to AD-dementia during 25-year follow-up (Nmax = 1,145), complemented with Cox proportional regression models to determine risk factors for conversion to clinical AD.

Results

Two personality factors, Closeness to Experience (CE: avoidance of new stimuli, high anxiety, pessimistic anticipation, low reward seeking) and Tendence to Liabilities (TL: inability to change, low autonomy, unaware of the value of their existence) were associated with higher levels of depressive symptoms, stress (CE), sleep disturbance (TL), as well as greater decline in memory, vocabulary and verbal fluency in the full sample. Higher CE was additionally associated with greater memory decline across 25 years in the healthy subsample, and faster right hippocampal volume reduction across 8 years in a neuroimaging subsample (N = 216). Most, but not all, personality-cognition associations persisted after controlling for diabetes, hypertension and cardiovascular disease. Concerning risks for conversion to AD, higher age, and APOE-ε4, but none of the personality measures, were significant predictors.

Conclusion

The results indicate that personality traits associated with psychiatric symptoms predict accelerated age-related neurocognitive declines even in the absence of neurodegenerative disease. The attenuation of some personality effects on cognition after adjustment for health indicators suggests that those effects may be partly mediated by somatic health. Taken together, the results further emphasize the importance of personality traits in neurocognitive aging and underscore the need for an integrative (biopsychosocial) perspective of normal and pathological age-related cognitive decline.

Mid-life adherence to the Dietary Approaches to Stop Hypertension (DASH) diet and late-life subjective cognitive complaints in women

INTRODUCTION

Evidence is limited on the role of mid-life Dietary Approaches to Stop Hypertension (DASH) diet in late-life subjective cognitive complaints (SCCs).

METHODS

We included 5116 women (mean age in 1985-1991: 46 years) from the New York University Women's Health Study. SCCs were assessed from 2018 to 2020 (mean age: 79 years) by a 6-item questionnaire.

RESULTS

Compared to women in the bottom quartile of the DASH scores, the odds ratio (OR) for having two or more SCCs was 0.83 (95% confidence interval: 0.70-0.99) for women in the top quartile of DASH scores at baseline (P for trend = 0.019). The association was similar with multiple imputation and inverse probability weighting to account for potential selection bias. The inverse association was stronger in women without a history of cancer (P for interaction = 0.003).

DISCUSSION

Greater adherence to the DASH diet in mid-life was associated with lower prevalence of late-life SCCs in women.

Alzheimer's Disease Prevention and Treatment Based on Population-Based Approaches

The development of effective prevention and treatment strategies for Alzheimer's disease (AD) and dementia is hindered by limited knowledge of the underlying biological and environmental causes. While certain genetic factors have been associated with AD, and various lifestyle and environmental factors have been linked to dementia risk, the interactions between genes and the environment are not yet fully understood. To identify new avenues for dementia prevention, coordinated global efforts are needed to utilize existing cohorts and resources effectively and efficiently. This chapter provides an overview of current research on risk and protective factors for AD and dementia and discusses the opportunities and challenges associated with population-based approaches.

Association of personality facets and cognition in the Lifelines population-based cohort study

BACKGROUND

Personality traits have been associated with cognitive functioning and risk of cognitive decline. Fewer studies have investigated how personality facets are associated with cognition in large cohorts with a prospective design.

METHODS

The association between eight personality facets and cognition (speed measures reflecting psychomotor speed and visual attention; hit rate measures reflecting visual learning and working memory) was analyzed in middle-aged adults from the Lifelines cohort (N = 79911; age 43 ± 11 years).

RESULTS

High hostility, high vulnerability, low excitement seeking, and low competence were associated with worse cognitive performance on all tasks. Impulsivity-related facets had weak and differential associations, with self-discipline negatively associated with accuracy and deliberation negatively associated with speed. These associations remained largely unchanged when accounting for lifestyle factors (smoking, alcohol consumption, physical activity). The associations with cognition were stronger in older people for impulsiveness, deliberation, and hostility, while stronger in younger people for excitement seeking, self-discipline, and vulnerability.

CONCLUSION

In a large population-based sample with a broad age range, the associations of personality facets with cognitive functioning had small effect sizes, were independent of lifestyle factors, and varied with age and among facets within the same personality domain. These findings highlight the importance of developmental stages and facet-level research in personality-cognition associations.

Are trajectories of personality and socioeconomic factors prospectively associated with midlife cognitive function? Findings from a 12-year longitudinal study of Mexican-origin adults

Problems with memory, executive function, and language are a significant public health concern, especially when they begin during midlife. However, there is relatively little work on risk and protective factors for cognitive function in middle adulthood. Using data from 883 Mexican-origin adults assessed up to 6 times across 12 years (Mage at Time 1 = 38.2 years; range = 27-63 years), the present study examined whether developmental trajectories (levels and slopes) of Big Five personality domains and socioeconomic factors (per capita income, economic stress) were prospectively associated with cognitive function (memory, mental status, verbal fluency) at the final assessment. We found that individuals with higher levels of, and smaller decreases in, Neuroticism had worse cognitive function 12 years later. Further, individuals with higher initial Conscientiousness had better subsequent memory, mental status, and verbal fluency, and individuals with higher Openness and Extraversion had better subsequent verbal fluency (but not memory or mental status). The trajectories of per capita income and economic stress were robustly associated with cognitive function, such that higher initial levels and greater increases in socioeconomic resources had protective associations, whereas higher levels and greater increases in economic stress had deleterious associations with cognitive function. Higher education level was associated with better cognitive function 12 years later. These findings suggest that changes in personality and socioeconomic factors across adulthood are associated with cognitive function, which may be informative for interventions to support healthier cognitive aging starting at least as early as midlife. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Anxiety disorders, benzodiazepine prescription, and incident dementia

BACKGROUND

Prescribing benzodiazepines to older patients is controversial. Anxiety disorders and benzodiazepines have been associated with dementia, but literature is inconsistent. It is unknown if anxiety treated with a benzodiazepine, compared to anxiety disorder alone is associated with dementia risk.

METHODS

A retrospective cohort study (n = 72,496) was conducted using electronic health data from 2014 to 2021. Entropy balancing controlled for bias by indication and other confounding factors.

PARTICIPANTS

Eligible patients were ≥65 years old, had clinic encounters before and after index date and were free of dementia for 2 years prior to index date. Of the 72,496 eligible patients, 85.6% were White and 59.9% were female. Mean age was 74.1 (SD ± 7.1) years.

EXPOSURE

Anxiety disorder was a composite of generalized anxiety disorder, anxiety not otherwise specified, panic disorder, and social phobia. Sustained benzodiazepine use was defined as at least two separate prescription orders in any 6-month period.

MAIN OUTCOME AND MEASURES

ICD-9 or ICD-10 dementia diagnoses.

RESULTS

Six percent of eligible patients had an anxiety diagnosis and 3.6% received sustained benzodiazepine prescriptions. There were 6640 (9.2%) incident dementia events. After controlling for confounders, both sustained benzodiazepine use (HR 1.28, 95% CI: 1.11-1.47) and a diagnosis of anxiety (HR 1.19, 95% CI: 1.06-1.33) were associated with incident dementia in patients aged 65-75. Anxiety disorder with sustained benzodiazepine, compared to anxiety disorder alone, was not associated with incident dementia (HR 1.18, 95% CI: 0.92-1.51) after controlling for confounding. Results were not significant when limiting the sample to those ≥75 years of age.

CONCLUSIONS

Benzodiazepines and anxiety disorders are associated with increased risk for dementia. In patients with anxiety disorders, benzodiazepines were not associated with additional dementia risk. Further research is warranted to determine if benzodiazepines are associated with a reduced or increased risk for dementia compared to other anxiolytic medications in patients with anxiety disorders.

Asthma Moderates the Association between the Big Five Personality Traits and Life Satisfaction

The current study aimed to examine whether asthma moderates the association between the Big Five personality traits and life satisfaction. By analyzing data from 3934 people with asthma (40.09% males) with a mean age of 49.2 (S.D. = 16.94) years old and 22,914 people without asthma (42.9% males) with a mean age of 45.62 (S.D. = 17.25) years old using a hierarchical regression and multiple regressions, the current study found that asthma significantly moderates the link between Neuroticism and life satisfaction and Openness and life satisfaction after controlling for other covariates. Specifically, Neuroticism was negatively related to life satisfaction whereas Agreeableness, Openness, Conscientiousness, and Extraversion were positively associated with life satisfaction in people with and without asthma. However, the negative association between Neuroticism and life satisfaction and the positive association between Openness and life satisfaction were stronger in people with asthma compared to people without asthma.

Can the Big Five personality traits predict ever chance and 7-year risk of clinically diagnosed chronic bronchitis in middle-aged and older adults?

OBJECTIVE

Chronic bronchitis refers to a chronic condition that is characterized by long-term inflammation of the bronchi. It is of great importance to understand the contributing risk factors for chronic bronchitis because it is associated with adverse outcomes such as healthcare burden and mortality. We aimed to understand if the personality traits could predict ever and the 7-year risk of clinically diagnosed chronic bronchitis in a large cohort of participants from the UK.

METHODS

We analyzed data from Understanding Society: the UK Household Longitudinal Study, which consists of 15,387 middle-aged or older participants for the cross-sectional analysis and 8783 middle-aged or older adults for the longitudinal analysis using two binary logistic regressions.

RESULTS

We found that Neuroticism (OR = 1.36, p < 0.001, 95% C.I. [1.23, 1.51]), Conscientiousness (OR = 0.87, p = 0.014, 95% C.I. [0.78, 0.97]), and Extraversion (OR = 1.15, p = 0.009, 95% C.I. [1.04, 1.29]) are related to a higher chance of ever clinically diagnosed chronic bronchitis. However, Agreeableness and Openness were not related to the chance of ever clinically diagnosed chronic bronchitis. Moreover, Conscientiousness (OR = 0.72, p = 0.012, 95% C.I. [0.55, 0.93]) was related to a lower risk of future clinical diagnosis of chronic bronchitis whereas Extraversion (OR = 1.35, p = 0.024, 95% C.I. [1.04, 1.76]) was associated with a higher risk of future chronic bronchitis. However, Neuroticism, Agreeableness, and Openness were not related to change of ever clinically diagnosed chronic bronchitis.

CONCLUSION

We showed that personality can identify people who are at greater risk of chronic bronchitis, which has translational utility for healthcare of middle-aged and older adults.

Understanding the Role of Cancer Diagnosis in the Associations between Personality and Life Satisfaction

Life satisfaction refers to the degree a person enjoys their life. An integrated account of life satisfaction is discussed in the literature, which proposes that life satisfaction is made up of personality traits and areas of life satisfaction (e.g., satisfaction with health, job, and social life). In addition, disruptions in one domain (e.g., health) may disrupt the association between personality traits and life satisfaction. The current research was interested in if clinically diagnosed cancer could influence the association between the Big Five personality traits and life satisfaction. The current study analyzed data from 1214 people with a diagnosis of cancer (38.55% males) with an average age of 59.70 (S.D. = 15.53) years and 13,319 people without a cancer diagnosis (38.13% males) with an average age of 59.97 (S.D. = 11.10) years who participated in Understanding Society: the UK Household Longitudinal Study (UKHLS). For the first time, our study revealed that cancer markedly influences the relationship between Agreeableness and life satisfaction, after accounting for demographic variables. Neuroticism was negatively associated with life satisfaction in people with and without clinically diagnosed cancer, whereas Agreeableness and Extraversion were positively associated with life satisfaction in people with and without clinically diagnosed cancer. Openness and Conscientiousness were positively related to life satisfaction in people without cancer but were not significant predictors in people with cancer. Health professionals should develop strategies and interventions by fostering personality traits, including Agreeableness, Openness, Conscientiousness, and Extraversion, while reducing Neuroticism.

The neurobiology of openness as a personality trait

Openness is a multifaceted behavioral disposition that encompasses personal, interpersonal, and cultural dimensions. It has been suggested that the interindividual variability in openness as a personality trait is influenced by various environmental and genetic factors, as well as differences in brain functional and structural connectivity patterns along with their various associated cognitive processes. Alterations in degree of openness have been linked to several aspects of health and disease, being impacted by both physical and mental health, substance use, and neurologic conditions. This review aims to explore the current state of knowledge describing the neurobiological basis of openness and how individual differences in openness can manifest in brain health and disease.

PRedicting the EVolution of SubjectIvE Cognitive Decline to Alzheimer's Disease With machine learning: the PREVIEW study protocol

BACKGROUND

As disease-modifying therapies (DMTs) for Alzheimer's disease (AD) are becoming a reality, there is an urgent need to select cost-effective tools that can accurately identify patients in the earliest stages of the disease. Subjective Cognitive Decline (SCD) is a condition in which individuals complain of cognitive decline with normal performances on neuropsychological evaluation. Many studies demonstrated a higher prevalence of Alzheimer's pathology in patients diagnosed with SCD as compared to the general population. Consequently, SCD was suggested as an early symptomatic phase of AD. We will describe the study protocol of a prospective cohort study (PREVIEW) that aim to identify features derived from easily accessible, cost-effective and non-invasive assessment to accurately detect SCD patients who will progress to AD dementia.

METHODS

We will include patients who self-referred to our memory clinic and are diagnosed with SCD. Participants will undergo: clinical, neurologic and neuropsychological examination, estimation of cognitive reserve and depression, evaluation of personality traits, APOE and BDNF genotyping, electroencephalography and event-related potential recording, lumbar puncture for measurement of Aβ42, t-tau, and p-tau concentration and Aβ42/Aβ40 ratio. Recruited patients will have follow-up neuropsychological examinations every two years. Collected data will be used to train a machine learning algorithm to define the risk of being carriers of AD and progress to dementia in patients with SCD.

DISCUSSION

This is the first study to investigate the application of machine learning to predict AD in patients with SCD. Since all the features we will consider can be derived from non-invasive and easily accessible assessments, our expected results may provide evidence for defining cost-effective and globally scalable tools to estimate the risk of AD and address the needs of patients with memory complaints. In the era of DMTs, this will have crucial implications for the early identification of patients suitable for treatment in the initial stages of AD.

TRIAL REGISTRATION NUMBER (TRN)

NCT05569083.

Diabetes Moderates the Link between Personality Traits and Self-Rated Health (SRH)

OBJECTIVES

The primary objective of this study is to explore the relationship between personality traits and self-rated health (SRH) in individuals with diabetes, while also comparing these associations with a group of healthy controls.

METHODS

The data for this study were obtained from the UK Household Longitudinal Study (UKHLS), comprising a sample of 1860 diabetes patients and 12,915 healthy controls who were matched in terms of age and sex. Hierarchical linear regression was utilized to analyze the data. The analysis included demographic variables such as age, sex, monthly income, highest educational qualification, marital status, and psychological distress assessed through the GHQ-12, personality traits, including Neuroticism, Agreeableness, Openness, Conscientiousness, and Extraversion, and diabetes status (0 for diabetes patients, 1 for healthy controls) as predictors. Interactions between personality traits and diabetes status were also included as predictors, with SRH serving as the dependent variable. Additionally, separate multiple regression analyses were conducted for diabetes patients and healthy controls, incorporating demographic variables, psychological distress, and personality traits as predictors, while SRH remained the dependent variable.

RESULTS

The findings of this study indicate that diabetes significantly moderates the association between Neuroticism and SRH. Specifically, both Neuroticism and Extraversion were negatively associated with SRH, whereas Openness and Conscientiousness exhibited a positive association with SRH in healthy controls. However, among diabetes patients, only Conscientiousness showed a positive association with SRH.

CONCLUSION

Personality traits predict SRH in people with and without diabetes differently. Healthcare professionals and clinicians should try to come up with ways that improve SRH and thus better outcomes in diabetes patients based on the findings from the current study.

Self-rated health (SRH) partially mediates and associations between personality traits and life satisfaction in older adults

It is established that personality traits contribute to life satisfaction but why they are connected are far less understood. This research report tested if self-rated health (SRH) which is one's subjective ratings of their health and has a high predictivity of actual health mediates the associations between the Big Five model of personality and life satisfaction in a cohort (N = 5,845) of older adults from the UK. By using Pearson's correlation analysis and mediation analysis, the current research reported positive correlations between Agreeableness, Openness, Conscientiousness, and Extraversion, SRH, and life satisfaction. However, Neuroticism was negatively correlated with SRH and life satisfaction. The main findings were that SRH partially mediates the associations between all traits in the Big Five and life satisfaction in older adults. This study began novel exploration on if SRH could explain the connections between the Big Five and life satisfaction. Results revealed SRH could partially explain these associations in all traits. These results may offer additional support to recently developed integrated account of life satisfaction, which argues that there are no single determinants of life satisfaction. Rather, life satisfaction is made up by many factors including but not limited to personality and health.

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.

The contributions of mitochondrial and nuclear mitochondrial genetic variation to neuroticism

Neuroticism is a heritable trait composed of separate facets, each conferring different levels of protection or risk, to health. By examining mitochondrial DNA in 269,506 individuals, we show mitochondrial haplogroups explain 0.07-0.01% of variance in neuroticism and identify five haplogroup and 15 mitochondria-marker associations across a general factor of neuroticism, and two special factors of anxiety/tension, and worry/vulnerability with effect sizes of the same magnitude as autosomal variants. Within-haplogroup genome-wide association studies identified H-haplogroup-specific autosomal effects explaining 1.4% variance of worry/vulnerability. These H-haplogroup-specific autosomal effects show a pleiotropic relationship with cognitive, physical and mental health that differs from that found when assessing autosomal effects across haplogroups. We identify interactions between chromosome 9 regions and mitochondrial haplogroups at P < 5 × 10-8, revealing associations between general neuroticism and anxiety/tension with brain-specific gene co-expression networks. These results indicate that the mitochondrial genome contributes toward neuroticism and the autosomal links between neuroticism and health.

Personality predicts self-rated health: considering age differences

Self-rated health (SRH) refers to the subjective evaluation of one's own health. Big Five personality traits including Neuroticism, Agreeableness, Openness, Conscientiousness, and Extraversion have been consistently found as significant predictors of SRH. In addition, SRH declines with age, and personality traits change with age. Thus, it is reasonable to speculate that age might moderate the associations between personality traits and SRH. The current study analyzed data from 33,256 participants with a mean age of 45.78 years old and 55.92% females. The current study found that age significantly moderates the associations between Agreeableness, Openness, and Conscientiousness and SRH after controlling for demographic covariates. The current study implies that personality traits relate to SRH differently at different ages. Thus, studies regarding the associations between personality traits and SRH must take the interactions between age and personality traits into account.

Five-Factor Model Personality Domains and Facets Associated with Markers of Cognitive Health

Using a diverse, age-stratified sample (N=3,478; age range 18-90) this study examines the cross-sectional association between five-factor model personality traits - domains and facets - and three measures of cognitive health - processing speed, visuospatial ability, subjective memory - and whether these associations vary by age, race, and ethnicity. Consistent with the literature on personality and cognitive health, higher openness and conscientiousness were associated with better cognitive performance and subjective memory, whereas higher neuroticism was associated with slower processing speed and worse subjective memory but was unrelated to visuospatial ability. Moderation analyses suggested some associations were stronger in midlife compared to younger and older adulthood but were generally similar across race and ethnicity. The facet-level analyses indicated the components of each domain most strongly associated with cognitive function (e.g., the responsibility facet of conscientiousness) and suggested some differences across facets within the same domain (e.g., depression was associated with worse performance, whereas anxiety was unrelated to performance; sociability was the only facet of extraversion associated with worse performance). The present research is consistent with the larger literature on personality and cognition and extends it by documenting similarities and differences across facets and demographic groups.

The Heritability of Subjective Cognitive Complaints in Older Australian Twins

BACKGROUND

Subjective cognitive complaints (SCCs) may be a precursor to mild cognitive impairment (MCI) and dementia.

OBJECTIVE

This study aimed to examine the heritability of SCCs, correlations between SCC and memory ability, and the influence of personality and mood on these relationships.

METHODS

Participants were 306 twin pairs. The heritability of SCCs and the genetic correlations between SCCs and memory performance, personality, and mood scores were determined using structural equation modelling.

RESULTS

SCCs were low to moderately heritable. Memory performance, personality and mood were genetically, environmentally, and phenotypically correlated with SCCs in bivariate analysis. However, in multivariate analysis, only mood and memory performance had significant correlations with SCCs. Mood appeared to be related to SCCs by an environmental correlation, whereas memory performance was related to SCCs by a genetic correlation. The link between personality and SCCs was mediated by mood. SCCs had a significant amount of both genetic and environmental variances not explained by memory performance, personality, or mood.

CONCLUSION

Our results suggest that SCCs are influenced both by a person's mood and their memory performance, and that these determinants are not mutually exclusive. While SCCs had genetic overlap with memory performance and environmental association with mood, much of the genetic and environmental components that comprised SCCs were specific to SCCs, though these specific factors are yet to be determined.

Exposure to negative socio-emotional events induces sustained alteration of resting-state brain networks in older adults

Basic emotional functions seem well preserved in older adults. However, their reactivity to and recovery from socially negative events remain poorly characterized. To address this, we designed a 'task-rest' paradigm in which 182 participants from two independent experiments underwent functional magnetic resonance imaging while exposed to socio-emotional videos. Experiment 1 (N = 55) validated the task in young and older participants and unveiled age-dependent effects on brain activity and connectivity that predominated in resting periods after (rather than during) negative social scenes. Crucially, emotional elicitation potentiated subsequent resting-state connectivity between default mode network and amygdala exclusively in older adults. Experiment 2 replicated these results in a large older adult cohort (N = 127) and additionally showed that emotion-driven changes in posterior default mode network-amygdala connectivity were associated with anxiety, rumination and negative thoughts. These findings uncover the neural dynamics of empathy-related functions in older adults and help understand its relationship to poor social stress recovery.

Network analysis of the associations between personality traits, cognitive functioning, and inflammatory markers in elderly individuals without dementia

Introduction

Lower cognitive functioning in old age has been associated with personality traits or systemic inflammatory markers. Associations have also been found between personality traits and inflammatory markers. However, no study has explored the inter-relationships between these three components simultaneously. The present study aims to better understand the inter-relationships among personality traits, inflammatory markers, and cognitive performance in elderly individuals without dementia.

Methods

This study utilizes a network analysis approach, a statistical method that allows visualization of the data's unique pairwise associations. We performed a cross-sectional analysis on 720 elderly individuals without dementia, using data from Colaus|PsyColaus, a population-based study conducted in Lausanne, Switzerland. The Revised NEO Five-Factor Inventory (NEO-FFI-R) was used to assess personality traits, and interleukin (IL)-1β, IL-6, tumor necrosis factor-α (TNF-α), and C-reactive protein (CRP) were used as peripheral inflammatory markers. Cognitive domains were investigated using the Mini-Mental State Examination (MMSE), the Verbal Fluency Test, the Stroop Test, the DO40, and the Free and Cued Selective Reminding (FCSR) test.

Results

Openness was associated with verbal fluency and Agreeableness with immediate free recall. In contrast, no association between inflammatory markers and personality traits or cognition was identified.

Discussion

In elderly individuals without dementia, a high level of Openness or Agreeableness was associated with executive functioning/semantic memory and episodic memory, respectively.

Linking the Amyloid, Tau, and Mitochondrial Hypotheses of Alzheimer's Disease and Identifying Promising Drug Targets

Damage or loss of brain cells and impaired neurochemistry, neurogenesis, and synaptic and nonsynaptic plasticity of the brain lead to dementia in neurodegenerative diseases, such as Alzheimer's disease (AD). Injury to synapses and neurons and accumulation of extracellular amyloid plaques and intracellular neurofibrillary tangles are considered the main morphological and neuropathological features of AD. Age, genetic and epigenetic factors, environmental stressors, and lifestyle contribute to the risk of AD onset and progression. These risk factors are associated with structural and functional changes in the brain, leading to cognitive decline. Biomarkers of AD reflect or cause specific changes in brain function, especially changes in pathways associated with neurotransmission, neuroinflammation, bioenergetics, apoptosis, and oxidative and nitrosative stress. Even in the initial stages, AD is associated with Aβ neurotoxicity, mitochondrial dysfunction, and tau neurotoxicity. The integrative amyloid-tau-mitochondrial hypothesis assumes that the primary cause of AD is the neurotoxicity of Aβ oligomers and tau oligomers, mitochondrial dysfunction, and their mutual synergy. For the development of new efficient AD drugs, targeting the elimination of neurotoxicity, mutual potentiation of effects, and unwanted protein interactions of risk factors and biomarkers (mainly Aβ oligomers, tau oligomers, and mitochondrial dysfunction) in the early stage of the disease seems promising.

Locus coeruleus catecholamines link neuroticism and vulnerability to tau pathology in aging

Higher neuroticism is a risk factor for Alzheimer's disease (AD), and is implicated in disordered stress responses. The locus coeruleus (LC)-catecholamine system is activated during perceived threat and is a centerpiece of developing models of the pathophysiology of AD, as it is the first brain region to develop abnormal tau. We examined relationships among the "Big 5" personality traits, LC catecholamine synthesis capacity measured with [18F]Fluoro-m-tyrosine PET, and tau burden measured with [18F]Flortaucipir PET in cognitively normal older adults (n = 47). β-amyloid (Aβ) status was determined using [11C]Pittsburgh compound B PET (n = 14 Aβ positive). Lower LC catecholamine synthesis capacity was associated with higher neuroticism, more depressive symptoms as measured by the Geriatric Depression Scale, and higher amygdala tau-PET binding. Exploratory analyses with other personality traits revealed that low trait conscientiousness was also related to both lower LC catecholamine synthesis capacity, and more depressive symptoms. A significant indirect path linked both high neuroticism and low conscientiousness to greater amygdala tau burden via their mutual association with low LC catecholamine synthesis capacity. Together, these findings reveal LC catecholamine synthesis capacity to be a promising marker of affective health and pathology burden in aging, and identifies candidate neurobiological mechanisms for the effect of personality on increased vulnerability to dementia.

Personality Traits Predict Life Satisfaction in Coronary Heart Disease (CHD) Patients

Objectives: The objective of the current study is to establish the association between Big Five personality traits and life satisfaction in coronary heart disease (CHD) patients. Methods: The current study analyzed data from 566 patients with CHD with a mean age of 63.00 ± 15.23 years old (61.13% males) and 3018 healthy controls (63.95% females) with a mean age of 63.85 (S.D. = 9.59) years old from the UKHLS. A train-and-test approach accompanied by one-sample t-tests was used to analyze the differences in personality traits and life satisfaction between CHD patients and healthy controls while controlling for potential confounders. Two multiple regression models were applied to analyze the associations between personality traits and life satisfaction in CHD patients and healthy controls, respectively. Results: The current study found that CHD patients have lower conscientiousness scores than healthy controls. Moreover, neuroticism was negatively related to life satisfaction, and agreeableness, conscientiousness, and extraversion were positively related to life satisfaction in healthy controls. However, only neuroticism and agreeableness were related to life satisfaction in CHD patients. Conclusion: Health professionals and clinicians should utilize findings from the current study to make customized interventions based on CHD patients’ personality traits to gain better well-being outcomes such as life satisfaction.

Behavioral and psychological symptoms in neurodegenerative dementias: harbinger, follower, or constant collateral?

Neurodegenerative dementias such as the behavioral variant of frontotemporal dementia, Alzheimer's disease, and Parkinson's disease dementia are linked to various behavioral and psychological abnormalities. Whether these abnormalities precede, coincide or follow the onset of cognitive symptoms is still controversial in existing literature, with trajectories available so far dependent on types of dementia. The authors aim to review the different kinds of premorbid behavioral symptoms/personality traits associated with an increased risk of developing specific types of neurodegenerative dementia. Neuroticism has been associated with an increased risk of Alzheimer's disease and late-onset behavioral abnormalities with the behavioral variant of frontotemporal dementia. The presence of obsessive-compulsive spectrum disorders in Parkinson's disease dementia is also not rare. Analyzing this evidence, we propose "behavioral biomarkers" as neuroticism in Alzheimer's disease, late-onset behavioral abnormalities in behavioral variant of frontotemporal dementia, and obsessive-compulsive traits in Parkinson's disease dementia. These noninvasive behavioral biomarkers will be of immense help, particularly in developing countries, and will prevent the need for costlier investigations and aid in therapeutic strategies.

Extraversion Is Associated With Lower Brain Beta-Amyloid Deposition in Cognitively Normal Older Adults

Emerging evidence suggests that some personality traits may link to the vulnerability to or protection for Alzheimer’s disease (AD). A causal mechanism underlying this relationship, however, remains largely unknown. Using 18F-Florbetaben positron emission tomography (PET) binding to beta-amyloid (Aβ) plaques, a pathological feature of AD, and functional magnetic resonance imaging (fMRI), we investigated pathological and functional correlates of extraversion and neuroticism in a group of healthy young and older subjects. We quantified the level of brain Aβ deposition in older individuals. Brain activity was measured in young adults using a task-switching fMRI paradigm. When we correlated personality scores of extraversion and neuroticism with these pathological and functional measures, higher extraversion, but not neuroticism, was significantly associated with lower global Aβ measures among older adults, accounting for age and sex. This association was present across widespread brain regions. Among young subjects, higher extraversion was associated with lower activity during task switching in the anterior cingulate cortex, left anterior insular cortex, left putamen, and middle frontal gyrus bilaterally, while higher neuroticism was associated with increased activity throughout the brain. The present results suggest that possibly via efficient neuronal activity, extraversion, one of the lifelong personality traits, may confer the protective mechanism against the development of Aβ pathology during aging.

Facets of Personality and Risk of Cognitive Impairment: Longitudinal Findings in a Rural Community from Sardinia

Background: Few studies have examined the associations between personality facets and dementia risk and rarely included individuals from rural settings or with low education. Objective: To examine the association between personality and the risk of cognitive impairment. Methods: Participants (N = 1,668; age 50 to 94 at baseline; 56.4% women; 86.5% less than high school diploma) were from a rural region of Sardinia (Italy) who completed the Revised NEO Personality Inventory (NEO-PI-R) during the first wave (2001–2004) and the Mini-Mental State Examination (MMSE) at waves two to five (2005–2021). Cox regression was used to test personality and covariates as predictors of cognitive impairment based on MMSE education-adjusted cutoffs. Results: During the up to 18-year follow-up (M = 10.38; SD = 4.76), 187 individuals (11.2%) scored as cognitively impaired. Participants with higher neuroticism (particularly the depression facet [HR = 1.22, 95% CI = 1.06–1.40]), and lower agreeableness (particularly the modesty facet [HR = 0.83, 95% CI = 0.71–0.97]) and lower conscientiousness (particularly the dutifulness facet [HR = 0.78, 95% CI = 0.67–0.92]) were at higher risk of cognitive impairment. Lower warmth ([HR = 0.75, 95% CI = 0.65–0.87], facet of extraversion) and ideas ([HR = 0.76, 95% CI = 0.65–0.89], facet of openness) were also associated with increased risk of impairment. These associations were virtually unchanged in models that accounted for other risk factors, including smoking, depression, obesity, hypertension, diabetes, and apolipoprotein E (APOE) ɛ4 carrier status. Across the five domains, sex and the APOE variant did not moderate the associations. Conclusion: In a sample with demographic characteristics underrepresented in dementia research, this study identifies personality domains and facets most relevant to the risk of cognitive impairment.

Facets of conscientiousness and motoric cognitive risk syndrome

Conscientiousness is related to a lower risk of motoric cognitive risk syndrome (MCR), a pre-dementia syndrome characterized by slow gait speed and cognitive complaints. The present study examines which facets of conscientiousness are related to concurrent and incident MCR. Participants were dementia-free older adults aged 65-99 years (N = 6001) from the Health and Retirement Study (HRS). Baseline data on conscientiousness facets and MCR (cognitive complaints and gait speed) were collected in 2008/2010, along with the covariates: demographic factors, cognition, physical activity, disease burden, depressive symptoms, and body mass index (BMI). MCR was assessed again in 2012/2014 and 2016/2018. Controlling for demographic factors, higher industriousness was related to a nearly 30% lower likelihood of concurrent MCR (Odds Ratio [OR] = 0.75, 95%CI: 0.67-0.85, p < .001) and to about 60% reduced risk of incident MCR (Hazard ratio [HR] = 0.63, 95%CI: 0.56-0.71, p < .001). Self-control, order, and responsibility were also associated with a lower likelihood of concurrent (OR range: 0.82-0.88) and incident (HR range: 0.72-0.82) MCR. Traditionalism (HR = 0.84, 95%CI: 0.75-0.93, p < .01) and virtue (HR = 0.84, 95%CI: 0.75-0.93, p < .01) were related to a lower risk of incident MCR. Cognition, physical activity, disease burden, depressive symptoms, and BMI partially accounted for these associations. Industriousness is the facet of conscientiousness with the strongest association with risk of MCR. This facet could be targeted in interventions to reduce MCR and, ultimately, dementia.

Mediation of perceived stress and cortisol in the association between neuroticism and global cognition in older adults: A longitudinal study

Neuroticism has been associated with a greater dementia risk, but its association with cognitive decline in healthy older adults remains unclear. Stress has been proposed as one of the mechanisms that could explain this relationship. Our aim was to analyse, in healthy older people, the mediating role of perceived stress and the Hypothalamic-Pituitary-Adrenal (HPA) axis in the association between neuroticism and global cognition. At Waves 1 and 2 (4-year follow-up), 87 older people (49.4% women; M age = 65.08, SD = 4.54 at Wave 1) completed a neuropsychological battery and the Perceived Stress Scale (PSS), and provided saliva samples on two (Wave 1) and three (Wave 2) consecutive days to measure the wake-to-bed slope. In Wave 2, neuroticism was assessed with the NEO-Five-Factor Inventory. PSS, but not the wake-to-bed slope, mediated the negative associations between neuroticism and global cognition (Waves 1, 2 and change). Regarding gender differences, PSS (Waves 1, 2 and change) and the wake-to-bed slope (Wave 2 and change) mediated these associations in men. Our results suggest that perceived stress and HPA-axis dysregulation could act as mechanisms underlying the association between neuroticism and cognitive functioning and decline, at least in older men.

Large household reduces dementia mortality: A cross-sectional data analysis of 183 populations

BACKGROUND

Large households/families may create more happiness and offer more comprehensive healthcare among the members. We correlated household size to dementia mortality rate at population level for analysing its protecting role against dementia mortality.

METHODS

This is a retrospective cross-sectional study. Dementia specific mortality rates of the 183 member states of World Health Organization were calculated and matched with the respective country data on household size, Gross Domestic Product (GDP), urban population and ageing. Scatter plots were produced to explore and visualize the correlations between household size and dementia mortality rates. Pearson's and nonparametric correlations were used to evaluate the strength and direction of the associations between household size and all other variables. Partial correlation of Pearson's approach was used to identify that household size protects against dementia regardless of the competing effects from ageing, GDP and urbanization. Multiple regression was used to identify significant predictors of dementia mortality.

RESULTS

Household size was in a negative and moderately strong correlation (r = -0.6034, p < 0.001) with dementia mortality. This relationship was confirmed in both Pearson r (r = - 0.524, p<0.001) and nonparametric (rho  =  -0.579, p < 0.001) analyses. When we controlled for the contribution of ageing, socio-economic status and urban lifestyle in partial correlation analysis, large household was still in inverse and significant correlation to dementia mortality (r = -0.331, p <0.001). This suggested that, statistically, large household protect against dementia mortality regardless of the contributing effects of ageing, socio-economic status and urban lifestyle. Stepwise multiple regression analysis selected large household as the variable having the greatest contribution to dementia mortality with R2 = 0.263 while ageing was placed second increasing R2 to 0.259. GDP and urbanization were removed as having no statistically significant influence on dementia mortality.

CONCLUSIONS

While acknowledging ageing, urban lifestyle and greater GDP associated with dementia mortality, this study suggested that, at population level, household size was another risk factor for dementia mortality. As part of dementia prevention, healthcare practitioners should encourage people to increase their positive interactions with persons from their neighbourhood or other fields where large household/family size is hard to achieve.

The Association Between Five Factor Model Personality Traits and Verbal and Numeric Reasoning

Five-factor model (FFM) personality traits are related to basic cognitive functions and risk of cognitive impairment in late life. The present study addresses whether FFM traits are also associated with a more complex cognitive function, reasoning, across adulthood. We used seven samples to examine the relation between personality and verbal (total N= 39,177) and numeric (total N= 76,388) reasoning. A meta-analysis indicated higher Neuroticism was associated modestly with worse performance on verbal and numeric reasoning tasks. Openness was associated with better verbal reasoning and was unrelated to numeric reasoning. Surprisingly, Extraversion was associated modestly with worse performance in both domains, and Conscientiousness was essentially unrelated to reasoning. Agreeableness was unrelated to reasoning. There was significant heterogeneity across the samples but only limited evidence for moderation by age or sex. Consistent with other cognitive domains, the results suggested that Neuroticism is related to worse performance globally, whereas Openness tends to be associated with better verbal abilities. Among the unexpected findings was the better reasoning of introverts. The pattern also suggests that the common positive association between Conscientiousness and cognition does not extend to reasoning and suggests that Conscientiousness may support healthier cognitive aging through basic cognitive functions rather than through complex functions like reasoning.

Preliminary Support of a Behavioral Intervention for Trait Conscientiousness in Multiple Sclerosis

Background

Conscientiousness, or the proclivity for deliberation, achievement, and order, declines in many individuals with multiple sclerosis (MS). Decreased conscientiousness predicts future cognitive deterioration, brain atrophy, and employment loss in individuals with MS. As a psychological trait, it may be an actionable antecedent to these important outcomes. We pilot tested an application (app)-facilitated behavioral intervention to help adaptation to low conscientiousness and, in turn, improve employment.

Methods

Eleven individuals with MS (5 treatment, 6 control) with low conscientiousness were recruited for a 12-week randomized controlled trial. The treatment group received a newly developed behavioral treatment and smartphone app designed to help people behave more conscientiously, 2 teleconference booster sessions, and weekly telephone calls to monitor progress. Employment changes were recorded at baseline and follow-up. Patients provided detailed posttreatment interviews.

Results

Participant groups were matched on baseline age, sex, education, disease duration, hours worked, and conscientiousness. All participants in the treatment arm reported benefits, found the app easy to use, and would recommend it to others. The treatment group reported significantly more positive work outcomes relative to controls at follow-up (P = .028). Other positive life changes were described by treatment participants during post-treatment interviews.

Conclusions

These results support the hypothesis that behaviors typically associated with low conscientiousness may be addressed by behavioral therapy in the MS population. In addition to the positive employment changes in the treatment group, several other quality of life changes were described by study participants. Additional research is needed.

Agreeableness and Its Consequences: A Quantitative Review of Meta-Analytic Findings

Agreeableness impacts people and real-world outcomes. In the most comprehensive quantitative review to date, we summarize results from 142 meta-analyses reporting effects for 275 variables, which represent N > 1.9 million participants from k > 3,900 studies. Arranging variables by their content and type, we use an organizational framework of 16 conceptual categories that presents a detailed account of Agreeableness’ external relations. Overall, the trait has effects in a desirable direction for 93% of variables (grand mean [Formula: see text]). We also review lower order trait evidence for 42 variables from 20 meta-analyses. Using these empirical findings, in tandem with existing theory, we synthesize eight general themes that describe Agreeableness’ characteristic functioning across variables: self-transcendence, contentment, relational investment, teamworking, work investment, lower results emphasis, social norm orientation, and social integration. We conclude by discussing potential boundary conditions of findings, contributions and limitations of our review, and future research directions.

Personality Associations With Amyloid and Tau: Results From the Baltimore Longitudinal Study of Aging and Meta-analysis

BACKGROUND

Higher neuroticism and lower conscientiousness are risk factors for Alzheimer's disease and related dementias, but the underlying neuropathological correlates remain unclear. Our aim was to examine whether personality traits are associated with amyloid and tau neuropathology in a new sample and meta-analyses.

METHODS

Participants from the BLSA (Baltimore Longitudinal Study of Aging) completed the Revised NEO Personality Inventory and underwent amyloid (11C-labeled Pittsburgh compound B) and tau (18F-flortaucipir) positron emission tomography.

RESULTS

Among cognitively normal BLSA participants, neuroticism was associated with higher cortical amyloid burden (odds ratio 1.68, 95% CI 1.20-2.34), and conscientiousness was associated with lower cortical amyloid burden (odds ratio 0.61, 95% CI 0.44-0.86). These associations remained significant after accounting for age, sex, education, depressive symptoms, hippocampal volume, and APOE ε4. Similar associations were found with tau in the entorhinal cortex. Random-effects meta-analyses of 12 studies found that higher neuroticism (N = 3015, r = 0.07, p = .008) and lower conscientiousness (N = 2990, r = -0.11, p < .001) were associated with more amyloid deposition. Meta-analyses of 8 studies found that higher neuroticism (N = 2231, r = 0.15, p < .001) and lower conscientiousness (N = 2206, r = -0.14, p < .001) were associated with more tau pathology. The associations were moderated by cognitive status, with stronger effects in cognitively normal compared with heterogeneous samples, suggesting that the associations between personality and proteopathies are not phenomena that emerge with neuropsychiatric clinical symptoms.

CONCLUSIONS

By aggregating results across samples, this study advances knowledge on the association between personality and neuropathology. Neuroticism and conscientiousness may contribute to resistance against amyloid and tau neuropathology.

Prospective self- and informant-personality associations with inflammation, health behaviors, and health indicators

OBJECTIVE

Personality influences many aspects of the health process. It is unclear to what extent self- and informant-reports of the Big Five offer incremental validity for the prediction of inflammatory biomarkers and whether inflammation provides a unique pathway between personality and indicators of physical health, independent of health behaviors.

METHOD

Using data from older adults (N = 1,630) enrolled in the St. Louis Personality and Aging Network study, we tested whether self- and informant-reported Big Five traits show unique associations with inflammation (IL-6, CRP, TNF-α). Further, we tested whether inflammation and health behaviors indirectly link personality to health-related quality of life, body mass index, and chronic disease burden using longitudinal mediation in a structural equation modeling framework.

RESULTS

Self-reports, informant-reports, and general trait factors of personality predicted future inflammatory biomarker levels (unstandardized regression coefficients ranged -.08 to .07 for self, -.13 to -.10 for informants, and -.16 to -.11 for general). Additionally, all assessment methods of personality were associated with the indicators of physical health through biomarker and health behavior pathways. Effects were primarily found for conscientiousness and neuroticism; IL-6 and CRP were the biomarkers with the most indirect effects; and indirect paths overall emerged more frequently through health behaviors, but this varied by outcome.

CONCLUSIONS

Self- and informant-reports provided unique predictive validity of inflammatory biomarkers. Findings highlight the benefits of using of multiple assessments of personality and the importance of examining multiple, distinct pathways by which personality might influence health to understand the mechanisms underlying this relationship more fully. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Do Personality Traits Influence the Association Between Depression and Dementia in Old Age?

Depression and personality traits are independent predictors of dementia or cognitive impairment. Despite the well-established relationship between these two psychosocial factors and dementia, no research has been documented on how personality traits can influence dementia in older adults exhibiting depressive symptoms. This study explores the influence of personality traits on the association between change in depression and dementia in old age. A population-based longitudinal cohort study involving two waves of data collected 5 years apart, containing 2210 American older adults, from the National Social Life, Health, and Aging Project to explore if personality traits influence how change in depression predicts the development of dementia. We assessed these relationships while adjusting for sociodemographic characteristics. Change in depression increased the likelihood of dementia at T2 by 4.2% (AOR = 1.04, p = 0.019) in the co-variate adjusted model. Personality traits, overall, did not influence how depression predicts the development of dementia. However, agreeableness individually nullified the effect of depression on the development of dementia, whereas extraversion was the only personality trait that significantly predicted dementia. Prosocial behaviors should be promoted in old age as these appear to be protective. In addition, early life education and a strong social support can keep the depression–dementia spectrum at bay in old age.