The genetics of human personality

A Comprehensive Aspect-Level Approach to the Personality Micro-Foundations of Foreign Policy Attitudes

We analyze in this article the effects of personality on attitudes toward foreign policy through a comprehensive aspect-level approach. We claim that previous observed null domain-level effects are the product of the aspect-level effects of opposing signs. By and large, we show that some personality effects are of comparable size or bigger than demographics studied in the literature, and that some of these effects are unique and independent of demographic covariates. Our results show that openness, orderliness, and compassion render people to be more supportive of cooperation. Assertiveness is the primary driver of support for the use of military force, whereas politeness and withdrawal ground reverse effects. Volatility roots isolationism postures, whereas industriousness, enthusiasm, and compassion show strong opposing effects. Moving beyond the Big Five personality domain approach provides us with a deeper and more nuanced understanding of how personality is associated with attitudes toward international issues.

Drift in Individual Behavioral Phenotype as a Strategy for Unpredictable Worlds

Individuals, even with matched genetics and environment, show substantial phenotypic variability. This variability may be part of a bet-hedging strategy, where populations express a range of phenotypes to ensure survival in unpredictable environments. In addition phenotypic variability between individuals ("bet-hedging"), individuals also show variability in their phenotype across time, even absent external cues. There are few evolutionary theories that explain random shifts in phenotype across an animals life, which we term drift in individual phenotype. We use individuality in locomotor handedness in Drosophila melanogaster to characterize both bet-hedging and drift. We use a continuous circling assay to show that handedness spontaneously changes over timescales ranging from seconds to the lifespan of a fly. We compare the amount of drift and bet-hedging across a number of different fly strains and show independent strain specific differences in bet-hedging and drift. We show manipulation of serotonin changes the rate of drift, indicating a potential circuit substrate controlling drift. We then develop a theoretical framework for assessing the adaptive value of drift, demonstrating that drift may be adaptive for populations subject to selection pressures that fluctuate on timescales similar to the lifespan of an animal. We apply our model to real world environmental signals and find patterns of fluctuations that favor random drift in behavioral phenotype, suggesting that drift may be adaptive under some real world conditions. These results demonstrate that drift plays a role in driving variability in a population and may serve an adaptive role distinct from population level bet-hedging.

Significance Statement

Why do individuals animals spontaneously change their preferences over time? While stable idiosyncratic behavioral preferences have been proposed to help species survive unpredictable environments as part of a bet-hedging strategy, the role of intraindividual shifts in preferences is unclear. Using Drosophila melanogaster , we show the stability of individual preferences is influenced by genetic background and neuromodulation, and is therefore a regulated phenomenon. We use theoretical modeling to show that shifts in preferences may be adaptive to environments that change within an individual's lifespan, including many real world patterns of environmental fluctuations. Together, this work suggests that the stability of individual preferences may affect the survival of species in unpredictable worlds - understanding that may be increasingly important in the face of anthropogenic change.

Equation for Attractiveness: Integrating Multidimensional Factors Through Computational Neuroaesthetics

BACKGROUND

Understanding the multifaceted nature of attractiveness (A), which encompasses physical beauty (PB), genuineness (GEN), self-confidence (SC), and prior experience (RE), is crucial for various domains, including psychology and clinical aesthetics. Previous studies have often isolated specific elements, failing to capture their intricate interplay. This study aims to develop a comprehensive equation for attractiveness using computational neuroaesthetics.

METHOD

The study began with a pilot study involving 250 participants (50 experts and 200 laypersons) who prerated 500 facial images on a Likert scale for traits such as physical beauty, genuineness, self-confidence, and perceived prior experience. Following the pilot, the main study recruited 11,780 participants through diverse media channels to rate a new set of 1,000 facial images. Advanced computational techniques, including multiple linear regression and Bayesian hierarchical modelling, were employed to analyse the data and formulate an attractiveness equation.

RESULTS

The analysis identified genuineness as the most significant factor, followed by physical beauty, self-confidence, and prior experience. The proposed equation for attractiveness, refined through Bayesian modelling, is:A = β 0 + ( β 1 · PB + β 2 · GEN + β 3 · SC + β 4 · PE ) + ϵ A = 1.82 + ( 0.34 · PB + 0.44 · GEN + 0.26 · SC + 0.16 · PE ) + ϵ (β0 is the intercept; β1, β2, β3, β4 are the coefficients for each factor; and ϵ is the error term) CONCLUSION: The findings underscore the paramount importance of psychological traits in attractiveness assessments, suggesting a shift from purely physical enhancements to holistic interventions in clinical settings. This model provides a robust framework for understanding attractiveness and has potential applications in psychology, marketing, and AI.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Alcohol sipping patterns, personality, and psychopathology in Children: Moderating effects of dorsal anterior cingulate cortex (dACC) activation

BACKGROUND

Alcohol, the most consumed drug in the United States, is associated with various psychological disorders and abnormal personality traits. Despite extensive research on adolescent alcohol consumption, the impact of early alcohol sipping patterns on changes in personality and mental health over time remains unclear. There is also limited information on the latent trajectory of early alcohol sipping, beginning as young as 9-10 years old. The dorsal anterior cingulate cortex (dACC) is crucial for cognitive control and response inhibition. However, the role of the dACC remains unclear in the relationship between early alcohol sipping and mental health outcomes and personality traits over time.

METHODS

Utilizing the large data from the Adolescent Brain Cognitive Development study (N = 11,686, 52% males, 52% white, mean [SD] age 119 [7.5] months, 9807 unique families, 22 sites), we aim to comprehensively examine the longitudinal impact of early alcohol sipping patterns on psychopathological measures and personality traits in adolescents, filling crucial gaps in the literature.

RESULTS

We identified three latent alcohol sipping groups, each demonstrating distinct personality traits and depression score trajectories. Bilateral dACC activation during the stop-signal task moderated the effect of early alcohol sipping on personality and depression over time. Additionally, bidirectional effects were observed between alcohol sipping and personality traits.

CONCLUSIONS

This study provides insights into the impact of early alcohol consumption on adolescent development. The key finding of our analysis is that poor response inhibition at baseline, along with increased alcohol sipping behaviors may accelerate the changes in personality traits and depression scores over time as individuals transition from childhood into adolescence.

What if some people just do not like science? How personality traits relate to attitudes toward science and technology

As societal discussion on the public opinion of science and technology ignites over and over again, understanding where such opinions are rooted is increasingly relevant. A handful of prior studies have suggested personality traits as a root of science and technology attitudes. However, these report mixed findings, and employ small student or convenience samples. This leaves considerable uncertainty regarding personality traits' relation to attitudes toward science and technology. If in fact stable psychological predispositions play a role, this has considerable implications for science policy and science communication. This article investigates the relationship between the big five personality traits and science attitudes in Germany and the Netherlands. Findings indicate that personality traits are related to science attitudes but only very weakly so, among them openness to experience and negative emotionality are most notably related to science attitudes, whereas extraversion, in contrast to prior studies, shows no relation to science and technology attitudes.

Personality correlates of past-year alcohol use in individuals with severe alcohol use disorder and a lifetime history of involvement in alcoholics anonymous

BACKGROUND

Alcohol use disorder (AUD) is a highly impairing condition with important public health impacts. Despite the availability of treatment options for AUD, research shows that few people receive treatment, and even fewer can maintain abstinence/low-drinking levels. This study investigated the role of personality traits in past-year alcohol use among individuals with severe AUD who ever attended Alcoholics Anonymous (AA), a widespread and easily accessible self-help group for alcohol problems.

METHODS

Univariable and multivariable regressions were performed separately in females and males with alcohol consumption as an outcome. Socioeconomic factors, genetic liability, and psychopathology were included as covariates in the analyses.

RESULTS

Results from the multivariable model indicated that in females who attended AA, greater alcohol use was related to both positive and negative urgency and low sensation seeking, while in males, greater alcohol use was related to positive urgency. Results also showed that, in both sexes, younger age and lower educational levels were associated with greater alcohol use. Moreover, single males and individuals with lower AUD severity were at higher risk of using alcohol in the past year.

CONCLUSIONS

These findings highlight sex-specific correlates of drinking in individuals with AUD who engaged in self-help groups. These findings may help to improve treatment options, as personality encompasses modifiable traits that can be targeted in psychological interventions.

Association between dopamine receptor D2 Taq IA gene polymorphism (rs1800497) and personality traits

Objective

This study aimed to find a potential association between the DRD2 Taq1A gene polymorphism (rs1800497 C32806T) and personality traits.

Methods

In all, 249 youths were recruited for this study. The Short-form Revised Eysenck Personality Questionnaire was administered to assess personality traits. The participants were genotyped for the DRD2 Taq1A polymorphism using the polymerase chain reaction-restriction fragment length polymorphism method. Statistical analysis was carried out to find a possible association between the genotypes and aspects of personality traits assessed.

Results

The frequencies of the A1 and A2 alleles in our sampled population were 215 (43.2%) and 283 (56.8%), while the frequencies of A1A1, A1A2, and A2A2 were 67 (26.9%), 81 (32.5%), and 101 (40.6%), respectively. The study population was not in Hardy-Weinberg equilibrium (χ2 = 17.64, p < 0.001). The A2 allele was significantly associated with extraversion. Although this allele was also associated with neuroticism, psychoticism, and lie, the association was not significant.

Conclusion

The A2 allele of the DRD2 Taq1A polymorphism was found to be more associated with extraversion, as measured by the Short-form Revised Eysenck Personality Questionnaire.

Multiple sclerosis and personality traits: associations with depression and anxiety

BACKGROUND

Depression and anxiety are commonly observed in people with multiple sclerosis (pwMS). There is a growing body of literature supporting the hypothesis that personality traits can influence the mood disorders. This study aimed to investigate the personality traits and their relationships with depression and anxiety among pwMS.

METHODS

234 pwMS were involved in this cross-sectional study. Personality traits, depression, and anxiety were assessed using the NEO Five-Factor Inventory (NEO-FFI) and Hospital Anxiety and Depression Scale (HADS), respectively. Pearson's correlation coefficient and generalized linear model were employed to evaluate the relationships between demographic and clinical characteristics, NEO-FFI, and HADS subscales.

RESULTS

In pwMS, longer disease duration was significantly associated with lower level of conscientiousness (β = - 0.23, p = 0.008) and agreeableness (β = - 0.2, p = 0.01). Moreover, higher expanded disability status scale (EDSS) of pwMS had a significant relationship with higher level of neuroticism (β = 0.89, p = 0.01). Increased level of neuroticism was significantly correlated with lower level of extraversion (r = - 0.28, p < 0.001), openness (r = - 0.37, p < 0.001), agreeableness (r = - 0.31, p < 0.001), and conscientiousness (r = - 0.45, p < 0.001). PwMS with higher level of conscientiousness showed more extraversion (r = 0.23, p < 0.001), openness (r = 0.61, p < 0.001), and agreeableness (r = 0.41, p < 0.001). Elevated level of neuroticism was significantly associated with higher level of anxiety (β = 0.47, p < 0.001) and depression (β = 0.11, p < 0.001) among pwMS.

CONCLUSION

The co-occurrence of depression and anxiety is probably associated with neuroticism among pwMS. Additionally, the impact of personality traits extends to influencing key disease aspects such as physical disability and disease duration in MS.

Assessing the genetic contribution of cumulative behavioral factors associated with longitudinal type 2 diabetes risk highlights adiposity and the brain-metabolic axis

While genetic factors, behavior, and environmental exposures form a complex web of interrelated associations in type 2 diabetes (T2D), their interaction is poorly understood. Here, using data from ~500K participants of the UK Biobank, we identify the genetic determinants of a "polyexposure risk score" (PXS) a new risk factor that consists of an accumulation of 25 associated individual-level behaviors and environmental risk factors that predict longitudinal T2D incidence. PXS-T2D had a non-zero heritability (h2 = 0.18) extensive shared genetic architecture with established clinical and biological determinants of T2D, most prominently with body mass index (genetic correlation [rg] = 0.57) and Homeostatic Model Assessment for Insulin Resistance (rg = 0.51). Genetic loci associated with PXS-T2D were enriched for expression in the brain. Biobank scale data with genetic information illuminates how complex and cumulative exposures and behaviors as a whole impact T2D risk but whose biology have been elusive in genome-wide studies of T2D.

Getting it right: Teaching undergraduate biology to undermine racial essentialism

How we teach human genetics matters for social equity. The biology curriculum appears to be a crucial locus of intervention for either reinforcing or undermining students' racial essentialist views. The Mendelian genetic models dominating textbooks, particularly in combination with racially inflected language sometimes used when teaching about monogenic disorders, can increase middle and high school students' racial essentialism and opposition to policies to increase equity. These findings are of particular concern given the increasing spread of racist misinformation online and the misappropriation of human genomics research by white supremacists, who take advantage of low levels of genetics literacy in the general public. Encouragingly, however, teaching updated information about the geographical distribution of human genetic variation and the complex, multifactorial basis of most human traits, reduces students' endorsement of racial essentialism. The genetics curriculum is therefore a key tool in combating misinformation and scientific racism. Here, we describe a framework and example teaching materials for teaching students key concepts in genetics, human evolutionary history, and human phenotypic variation at the undergraduate level. This framework can be flexibly applied in biology and anthropology classes and adjusted based on time availability. Our goal is to provide undergraduate-level instructors with varying levels of expertise with a set of evidence-informed tools for teaching human genetics to combat scientific racism, including an evolving set of instructional resources, as well as learning goals and pedagogical approaches. Resources can be found at https://noto.li/YIlhZ5. Additionally, we hope to generate conversation about integrating modern genetics into the undergraduate curriculum, in light of recent findings about the risks and opportunities associated with teaching genetics.

A tri-directional examination of adolescent personality, perceived parenting, and economic and parental adversity contexts in influencing adolescent behavioral outcomes

INTRODUCTION

Adolescent personality is consistently linked to behavioral strengths and difficulties. However, most of this work is limited in that it does not consider personality beyond the Big Five or economic or parental adversity contexts. The Tri-Directional Framework of Parent and Offspring Traits and Outcomes highlights the collective influence of personality, parenting, and context on offspring behavioral outcomes.

METHODS

Parent and adolescent cross-sectional data were collected from 2019 to 2021 as part of the Parents and Children Together project in the United Kingdom. Adolescents (N = 310, 48.7% female) self-reported on Dark Triad traits, parenting, and behavior. Parents (N = 288, 46.9% mothers) self-reported on socioeconomic status and adverse childhood experiences. In two path analysis models, we examined: (1) adolescent Dark Triad, context, and their interactions as predictors of perceived maternal and paternal warmth, hostility, and control; and (2) adolescent Dark Triad, perceived parenting, context, and personality-parenting interactions as predictors of adolescent behavioral strengths and difficulties.

RESULTS

Adolescent narcissistic traits were the strongest predictors of perceived maternal parenting, whereas adolescent psychopathy and Machiavellianism were the strongest predictors of perceived paternal parenting. Adolescent personality interacted with contextual factors in predicting parenting, but not with perceived parenting in predicting behavior.

CONCLUSION

Adolescent Dark Triad traits, especially narcissism, and contextual factors are important for the parent-offspring relationship and developmental outcomes. We recommend that research move beyond assessing direct trait-outcome associations to examining how these associations operate in different environments.

Multivariate genetic analysis of personality and cognitive traits reveals abundant pleiotropy

Personality and cognitive function are heritable mental traits whose genetic foundations may be distributed across interconnected brain functions. Previous studies have typically treated these complex mental traits as distinct constructs. We applied the 'pleiotropy-informed' multivariate omnibus statistical test to genome-wide association studies of 35 measures of neuroticism and cognitive function from the UK Biobank (n = 336,993). We identified 431 significantly associated genetic loci with evidence of abundant shared genetic associations, across personality and cognitive function domains. Functional characterization implicated genes with significant tissue-specific expression in all tested brain tissues and brain-specific gene sets. We conditioned independent genome-wide association studies of the Big 5 personality traits and cognitive function on our multivariate findings, boosting genetic discovery in other personality traits and improving polygenic prediction. These findings advance our understanding of the polygenic architecture of these complex mental traits, indicating a prominence of pleiotropic genetic effects across higher order domains of mental function such as personality and cognitive function.

The genetics of neuroticism: Insights from the Maudsley rat model and human studies

We examine some of the genetic features of neuroticism (N) taking as an animal model the Maudsley Reactive (MR) and Maudsley Nonreactive (MNR) rat strains which were selectively bred, respectively, for high and low open-field defecation (OFD) starting in the late 1950s. To draw analogies with human genetic studies, we explore the genetic correlation of N with irritable bowel syndrome (IBS). We review progress with the rat model and developments in the field of human complex trait genetics, including genetic association studies that relate to current understanding of the genetics of N. The widespread differences in the tone of the peripheral sympathetic nervous system that have been found between the Maudsley strains, particularly those observed in the colon, may underly the differences in OFD (MNR, higher sympathetic tone and zero defecation). In humans, a large genome-wide association study (GWAS) reported six genes contributing to IBS, four of which were implicated in mood and anxiety disorders or were expressed in the brain, with three of the four also expressed in the nerve fibers and ganglia of the gut. Heritability of N is estimated at around 50% in twin and family studies, and GWASs identified hundreds of loci, enabling estimation of genome-wide correlations (rg) with other traits. Significantly, the estimate for rg between risk of IBS, anxiety, N, and depression was >0.5 and suggested genetic pleiotropy without evidence for causal mechanisms. Findings on the adrenergic pharmacology of the colon, coupled with new understanding of the role of the locus ceruleus in modifying afferent information from this organ, generate hypotheses that challenge traditional cause/effect notions about the relationship of the central nervous system to peripheral events in response to stress, suggest specific targets for gene action in the Maudsley model and emphasize the value of reciprocal evaluation of genetic architecture underlying N in rodents and humans.

Antagonistic interactions between odorants alter human odor perception

The olfactory system uses hundreds of odorant receptors (ORs), the largest group of the G-protein-coupled receptor (GPCR) superfamily, to detect a vast array of odorants. Each OR is activated by specific odorous ligands, and like other GPCRs, antagonism can block activation of ORs. Recent studies suggest that odorant antagonisms in mixtures influence olfactory neuron activities, but it is unclear how this affects perception of odor mixtures. In this study, we identified a set of human ORs activated by methanethiol and hydrogen sulfide, two potent volatile sulfur malodors, through large-scale heterologous expression. Screening odorants that block OR activation in heterologous cells identified a set of antagonists, including β-ionone. Sensory evaluation in humans revealed that β-ionone reduced the odor intensity and unpleasantness of methanethiol. Additionally, suppression was not observed when methanethiol and β-ionone were introduced simultaneously to different nostrils. Our study supports the hypothesis that odor sensation is altered through antagonistic interactions at the OR level.

Niche diversity effects on personality measurement - evidence from large national samples during the COVID-19 pandemic

We report systematic variability in the psychometric properties of a brief personality inventory during the early stages of the COVID-19 pandemic. Drawing upon recent discussions about the universality vs cultural relativism of personality measures, we review and comparatively test theories predicting systematic variability in personality measurement across cultures using an established brief personality measure applied to population samples in 16 nations during the first wave of the COVID-19 pandemic (N = 35,052). We found systematic variation in factor replicability and effective dimensionality. In line with previous theorizing, factors replicated better in contexts with greater niche diversity. Examining possible drivers underlying this association, the investigation of the individual components in the niche construction index suggested that life expectancy and to a lesser degree economic complexity are associated with greater personality structure differentiation. Population-level indicators of acute threat due to COVID-19 did not show credible effects. These patterns suggest that a) investigation of personality structure in population samples can provide useful insights into personality dynamics, b) socioecological factors have a systematic impact on survey responses, but c) we also need better theorizing and research about both personality and culture to understand how niche construction dynamics operate.

Association between personality and cognitive performance in middle-aged and older adults with human immunodeficiency virus (HIV)

BACKGROUND

Nearly half of adults with human immunodeficiency virus (HIV) experience HIV-Associated Neurocognitive Disorder (HAND), characterized by cognitive impairments in two or more cognitive domains, which can interfere with everyday functioning. Many factors are thought to influence such cognitive impairments in adults with HIV; one factor seldom examined is personality.

OBJECTIVE

This study investigated the association between five major dimensions of personality (openness, conscientiousness, extraversion, agreeableness, and neuroticism) and cognitive function in older adults with HIV.

METHODS

In this cross-sectional study, a secondary data analysis was conducted on 261 HIV + participants. Participants completed a norm-based cognitive battery covering seven cognitive domains, which yielded the following indices: global cognitive impairment, and global and domain-specific T-scores. The Big Five Inventory was used to assess personality traits.

RESULTS

Higher openness, conscientiousness, and agreeableness were associated with better performance on individual cognitive domains while agreeableness and openness were also positively associated with global cognitive T-scores (p < .01). Only openness significantly predicted global cognition when adjusting for covariates (p < .01).

DISCUSSION

Openness was associated with better global cognitive function in persons with HIV. This study provides a basis for further investigation of potential mechanisms for the association between personality and cognition in people with HIV in order to ultimately inform intervention strategies.

Stability of associations between neuroticism and microstructural asymmetry of the cingulum during late childhood and adolescence: Insights from a longitudinal study with up to 11 waves

Adolescence is characterized by significant brain development and marks a period of the life span with an increased incidence of mood disorders, especially in females. The risk of developing mood disorders is also higher in individuals scoring high on neuroticism, a personality trait characterized by a tendency to experience negative and anxious emotions. We previously found in a cross-sectional study that neuroticism is associated with microstructural left-right asymmetry of the fronto-limbic white matter involved in emotional processing, with opposite effects in female and male adolescents. We now have extended this work collecting longitudinal data in 76 typically developing children and adolescents aged 7-18 years, including repeated MRI sampling up to 11 times. This enabled us, for the first time, to address the critical question, whether the association between neuroticism and frontal-limbic white matter asymmetry changes or remains stable across late childhood and adolescence. Neuroticism was assessed up to four times and showed good intraindividual stability and did not significantly change with age. Conforming our cross-sectional results, females scoring high on neuroticism displayed increased left-right cingulum fractional anisotropy (FA), while males showed decreased left-right cingulum FA asymmetry. Despite ongoing age-related increases in FA in cingulum, the association between neuroticism and cingulum FA asymmetry was already expressed in females in late childhood and remained stable across adolescence. In males, the association appeared to become more prominent during adolescence. Future longitudinal studies need to cover an earlier age span to elucidate the time point at which the relationship between neuroticism and cingulum FA asymmetry arises.

Impact of the COVID-19 pandemic on women's perinatal mental health and its association with personality traits: An observational study

INTRODUCTION

The burden of perinatal mental health problems was expected to increase during the COVID-19 pandemic. We prospectively investigated the impact of the COVID-19 pandemic on the mental health of pregnant and postpartum women in Norway and explored associations with their sociodemographic characteristics and personality traits.

MATERIAL AND METHODS

Sociodemographic information and the self-reported impact of pandemic on wellbeing of pregnant women was collected using an online survey. To assess women's mental health, two validated questionnaires, the Edinburgh Postpartum Depression Scale (EPDS) and the Generalized Anxiety Disorder-7 item Scale (GAD-7), were used prenatally and postnatally. Personality traits were evaluated using HumanGuide, a web-based ipsative psychological evaluation instrument.

RESULTS

772 women were included prenatally, of which 526 also responded to the survey 4-6 weeks postnatally. The median age was 29 years, 53.6% of the women were nulliparous when enrolled, and 35.1% worked in the healthcare sector. The median EPDS (6.0; interquartile range [IQR] 3.0-10.0 vs 6.0; IQR: 3.0-10.0) and the median GAD-7 (5.0; IQR 2.0-9.0 vs 5.0; IQR 2.0-9.0) were similar pre-and postnatally. Prenatally, the proportion of women scoring ≥13 on EPDS and ≥10 on GAD-7 was 14.5% (112/772) and 21.5% (166/772), whereas the postnatal figures were 15.6% (82/526) and 21.5% (113/526), respectively. The differences were not significant (P = 0.59 and P = 0.99). Being <25 years of age, being on pre-pregnancy psychotherapy or psychotropic medication, frequent voluntary isolation, perception of maternity care not proceeding normally, avoiding seeking medical assistance due to fear of infection and having negative economic consequences during the COVID19 pandemic significantly increased the risk of both anxiety (GAD-7 ≥10) and depression (EPDS ≥13). Nullipara had a higher risk of anxiety, whereas being a healthcare worker had a lower risk. The personality trait factors Power (P = 0.008), Quality (P = 0.008), Stability (P < 0.001) and Contacts (P < 0.001) were significant predictors of depression among pregnant women, whereas the Quality (P = 0.005) and Contacts (P = 0.003) were significant predictors of anxiety.

CONCLUSIONS

During the initial phase of the COVID-19 pandemic, the prevalence of depression (EPDS ≥ 13) and anxiety (GAD-7 ≥ 10) was 14.5% and 21.5%, respectively, among Norwegian pregnant women. Certain sociodemographic characteristics and personality traits were significant predictors of depression and anxiety.

The emergence of genotypic divergence and future precision medicine applications

Genotypic divergence is a term adapted from population genetics and intimately linked to evolution. We use divergence here to emphasize the differences that set individuals apart in any cohort. The history of genetics is filled with descriptions of genotypic differences, but causal inference of interindividual biological variation has been scarce. We suggest that the practice of precision medicine requires a divergent approach, an approach dependent on the causal interpretation of previous convergent (and preliminary) knowledge in the field. This knowledge has relied on convergent descriptive syndromology (lumping), which has overemphasized a reductionistic gene determinism on the quest of seeking associations without causal understanding. Regulatory variants with small effect and somatic mutations are some of the modifying factors that lead to incomplete penetrance and intrafamilial variable expressivity often observed in apparently monogenic clinical disorders. A truly divergent approach to precision medicine requires splitting, that is, the consideration of different layers of genetic phenomena that interact causally in a nonlinear fashion. This chapter reviews convergences and divergences in genetics and genomics, aiming to discuss what can be causally understood to approximate the as-yet utopian lands of Precision Medicine for patients with neurodegenerative disorders.

Trait continuity: Can parent-rated infant temperament predict HEXACO personality in early adulthood?

Examining the Raine cohort study, we tested the trait continuity hypothesis by examining the extent that young adults' (25-29 years old) self-reported HEXACO personality can be statistically predicted from multi-dimensional parental temperament ratings collected in infancy (1-2 years old). The study incorporated a lagged design (two waves), a large sample size (n = 563), and examined both temperament and personality as both dimensions and profiles. Overall, we found very limited evidence of trait continuity, with generally very weak and few statistically significant observed associations of infant temperament with early adulthood personality. Relations were weak whether profile or dimension-based operationalizations of both phenomena were adopted. Additionally, controlling for sex affected the relations of temperament and personality only to a small extent for most of the traits, and moderation effects of sex were generally zero-to-trivial in size. Altogether, parent-rated temperament in infancy seems to provide little information about HEXACO personality in early adulthood.

Temperament traits mediate the relationship between CACNA1C polymorphisms and bipolar disorder in cisgender women

The influence of temperament traits on bipolar disorder (BD) has been investigated. Both temperament traits and BD are partially genetically determined and seem to be influenced by variations in the CACNA1C gene. These variations presented a significant interactive effect with biological sex, although studies that evaluate this relationship are scarce. Here, we assessed the mediation effect of temperament traits on the relationship between two polymorphisms in the CACNA1C gene (rs1006737 and rs4765913) and BD according to sex. This is a cross-sectional study consisting of 878 Caucasian individuals (508 women and 370 men), aged 18-35, enrolled in a population-based study in the city of Pelotas, Southern Brazil. BD diagnosis was evaluated using the clinical interview MINI 5.0, and temperament traits were assessed via the application of the Affective and Emotional Composite Temperament Scale (AFECTS). Mediation models were tested using the modeling tool PROCESS (version 3.3) for SPSS. Bootstrapping-enhanced mediation analyses in women indicated that traits anger (39%) and caution (27%) mediated the association between the rs4765913 SNP and BD, while traits volition (29%), anger (35%), and caution (29%) mediated the association between the AA haplotype (rs1006737-rs4765913) and the BD. No effect was encountered for cisgender men. Our model revealed that paths from CACNA1C SNPs to BD are mediated by specific temperament traits in women, reinforcing the definition of temperament traits as endophenotypes.

Relationship of DRD5 and MAO-B VNTR polymorphisms with paranoid and antisocial personality disorders in polydrug users

Although multiple studies have shown the role genetics plays in personality disorders and in addictions, few have studied the genetic aspects of their comorbidity. Here, we carried out a cross-sectional study in a sample comprising 303 Caucasian polydrug-consuming patients. The presence of personality disorders was evaluated using the International Personality Disorder Examination, and genes related to dopamine, serotonin and monoamine oxidase (MAO) were genotyped. A significant relationship was observed between the bp 279 DRD5 variable number of tandem repeat (VNTR) polymorphism and paranoid personality disorder OR 95 % CI = 2.186 1.074 ; 4.449 ; p = 0.006 . The bp 182 OR 95 % CI = 0.407 0.178 ; 0.931 ; p = 0.033 and bp 184 OR 95 % CI = 0.391 0.188 ; 0.813 ; p = 0.012 alleles of the MAOB VNTR were also associated with antisocial personality disorder. Among patients with addictions, paranoid personality disorder should also be considered in addition to the importance of antisocial and borderline personality disorders. The higher frequency of the bp 279 DRD5 VNTR allele found in patients with paranoid personality disorder, as well as the associations between alleles of the MAOB VNTR and antisocial personality disorder, support the monoaminergic bases of these personality disorders, especially when dealing with patients with addictions.

Genome-wide association study in a rat model of temperament identifies multiple loci for exploratory locomotion and anxiety-like traits

Common genetic factors likely contribute to multiple psychiatric diseases including mood and substance use disorders. Certain stable, heritable traits reflecting temperament, termed externalizing or internalizing, play a large role in modulating vulnerability to these disorders. To model these heritable tendencies, we selectively bred rats for high and low exploration in a novel environment [bred High Responders (bHR) vs. Low Responders (bLR)]. To identify genes underlying the response to selection, we phenotyped and genotyped 538 rats from an F₂ cross between bHR and bLR. Several behavioral traits show high heritability, including the selection trait: exploratory locomotion (EL) in a novel environment. There were significant phenotypic and genetic correlations between tests that capture facets of EL and anxiety. There were also correlations with Pavlovian conditioned approach (PavCA) behavior despite the lower heritability of that trait. Ten significant and conditionally independent loci for six behavioral traits were identified. Five of the six traits reflect different facets of EL that were captured by three behavioral tests. Distance traveled measures from the open field and the elevated plus maze map onto different loci, thus may represent different aspects of novelty-induced locomotor activity. The sixth behavioral trait, number of fecal boli, is the only anxiety-related trait mapping to a significant locus on chromosome 18 within which the Pik3c3 gene is located. There were no significant loci for PavCA. We identified a missense variant in the Plekhf1 gene on the chromosome 1:95 Mb QTL and Fancf and Gas2 as potential candidate genes that may drive the chromosome 1:107 Mb QTL for EL traits. The identification of a locomotor activity-related QTL on chromosome 7 encompassing the Pkhd1l1 and Trhr genes is consistent with our previous finding of these genes being differentially expressed in the hippocampus of bHR vs. bLR rats. The strong heritability coupled with identification of several loci associated with exploratory locomotion and emotionality provide compelling support for this selectively bred rat model in discovering relatively large effect causal variants tied to elements of internalizing and externalizing behaviors inherent to psychiatric and substance use disorders.

The social evolution of individual differences: Future directions for a comparative science of personality in social behavior

Personality is essential for understanding the evolution of cooperation and conflict in behavior. However, personality science remains disconnected from the field of social evolution, limiting our ability to explain how personality and plasticity shape phenotypic adaptation in social behavior. Researchers also lack an integrative framework for comparing personality in the contextualized and multifaceted behaviors central to social interactions among humans and other animals. Here we address these challenges by developing a social evolutionary approach to personality, synthesizing theory, methods, and organizing questions in the study of individuality and sociality in behavior. We critically review current measurement practices and introduce social reaction norm models for comparative research on the evolution of personality in social environments. These models demonstrate that social plasticity affects the heritable variance of personality, and that individual differences in social plasticity can further modify the rate and direction of adaptive social evolution. Future empirical studies of frequency- and density-dependent social selection on personality are crucial for further developing this framework and testing adaptive theory of social niche specialization.

Examining the Construct Validity of Borderline Personality Traits Using Familial Aggregation and Other External Validators

Numerous studies have questioned the reliability and validity of borderline personality disorder's (BPD) categorical conceptualization. DSM-5 Section III's alternative trait-based model of BPD may better capture borderline pathology, but aspects of its validity should be further established. Thus, the authors examined whether a latent BPD factor derived from Section III traits exhibits (1) familial aggregation among siblings and (2) association with constructs related to borderline pathology. The authors also tested whether gender moderated associations. A total of 498 community-recruited adults completed the Personality Inventory for DSM-5, a behavioral assessment of risk-taking, and reported their history of childhood maltreatment, substance use, nonsuicidal self-injury, and suicidal ideation. Familial aggregation was assessed among 232 sibling pairs. Siblings' BPD scores were significantly correlated and most external validators were significantly associated with BPD, with the exception of risk-taking. Results did not vary by gender. Findings further support the construct validity of Section III's BPD trait profile.

Analyzing the relationship between the personality traits of nursing students and their attitudes toward people with mental illnesses

PURPOSE

The aim is to analyze the relationship between the personality traits of nursing students and their attitudes toward people with mental illnesses.

DESIGN AND METHODS

The cross-sectional study constituted of 281 students. The Community Attitudes toward the Mentally Ill Scale and the Ten-Item Personality Inventory were used.

FINDINGS

The students who have mental illnesses or in their families showed a higher goodwill score. The openness to experience subscale was correlated with conscientiousness, extraversion, emotional stability, and agreeableness.

PRACTICE IMPLICATIONS

Organizing educational programs for nursing students focusing on developing a positive attitude toward people with mental illnesses is crucial.

Risk of Personality disorders among childhood maltreatment victims: A nation-wide population-based study in Taiwan

BACKGROUND

To date, numerous cohort studies and meta-analyses have shown that childhood maltreatment is associated with a wide range of adverse physiological and psychological symptoms. Although childhood maltreatment has been linked to an increased risk of personality disorders, the direction and magnitude of the association remain uncertain. Therefore, this cohort study aimed to evaluate whether children who have suffered childhood maltreatment have a higher incidence of subsequent personality disorders, using a nationwide database in Taiwan.

METHODS

We conducted a large retrospective cohort study using data drawn from Taiwan's National Health Insurance Research Database between 2000 and 2015. A total of 10,345 children who experienced childhood maltreatment were identified using International Classification of Disease codes. They were then compared with 41,380 children who never experienced childhood maltreatment in terms of the prevalence rates of personality disorders.

RESULTS

Childhood maltreatment was associated with an increased risk of personality disorders (considering the control as reference: adjusted hazard ratio, 2.12; 95% confidence interval, 1.90-2.36; p < 0.001). The Kaplan-Meier analysis revealed a significantly higher 15-year cumulative incidence of personality disorders among childhood maltreatment victims than among controls (log-rank test, p < 0.001).

CONCLUSIONS

The present population-based study showed a positive association between prior childhood maltreatment and subsequent personality disorders in the general Taiwanese population. In order to reduce the risk of personality disorders, interventions should be implemented, identifying and supporting economically disadvantaged families and vulnerable children as early as possible.

Predicting disordered gambling across adolescence and young adulthood from polygenic contributions to Big 5 personality traits in a UK birth cohort

BACKGROUND AND AIMS

Previous research has demonstrated phenotypical associations between disordered gambling (DG) and Big 5 personality traits, and a twin study suggested that shared genetic influences accounted for a substantial portion of this relation. The present study examined associations between DG and polygenic scores (PSs) for Big 5 traits to measure the shared genetic underpinnings of Big 5 personality traits and DG.

DESIGN

Zero-inflated negative binomial regression models estimated associations between Big 5 PSs and past-year and life-time assessments of DG in a longitudinally assessed population-based birth cohort.

SETTING

United Kingdom.

PARTICIPANTS

A total of 4729 unrelated children of European ancestry from the Avon Longitudinal Study of Parents and Children (ALSPAC) with both phenotypical and genetic data.

MEASUREMENTS

Phenotypical outcomes included past-year assessment of DG using the problem gambling severity index (PGSI) and life-time assessment of DSM-IV pathological gambling symptoms (DPG) across the ages of 17, 20 and 24 years. Polygenic scores were derived for the Big 5 personality traits of agreeableness, extraversion, conscientiousness, openness and neuroticism using summary statistics from genome-wide association studies (GWAS).

FINDINGS

PSs for agreeableness [β= - 0.25, standard error (SE) = 0.054, P = 3.031e-6, ΔR2  = 0.008] and neuroticism (β=0.14, SE = 0.046, P = 0.0017, ΔR2  = 0.002) significantly predicted PGSI scores over and above included covariates (i.e. sex and first five ancestral principal components). PSs for agreeableness (β= - 0.20, SE = 0.056, P = 0.00036, ΔR2  = 0.003) and neuroticism, when interactions with age were taken into account (β = 0.29, SE = 0.090, P = 0.002, ΔR2  = 0.004), also predicted DPG scores.

CONCLUSIONS

Polygenic contributions to low agreeableness and high neuroticism appear to predict two measures of disordered gambling (problem gambling severity index and life-time assessment of DSM-IV pathological gambling symptoms). Polygenic scores for neuroticism interact with age to suggest that the positive association becomes stronger from adolescence through young adulthood.

Effects of age on psychosocial working conditions and future labour market marginalisation: a cohort study of 56,867 Swedish twins

PURPOSE

Previous studies have reported an elevated risk of sickness absence (SA) and disability pension (DP) due to adverse psychosocial working conditions, yet the influence of age and familial factors on the associations have not been examined. We aimed to investigate associations between psychosocial working conditions and labour market marginalisation (LMM) in terms of unemployment, SA and DP adjusting for familial confounding and possible differences in these associations with different age groups and different unemployment and sick leave days.

METHODS

All twins living in Sweden in 2001, aged 16-64 years and not on old-age pension or DP were included (n = 56,867). The twins were followed from 2002 to 2016 regarding unemployment, SA and DP. Cox proportional hazards regression models were performed for the whole sample, and for discordant twin pairs, in five age groups.

RESULTS

Each one-unit increase in job demands and job control was associated with a lower risk of unemployment, SA and DP in all age groups. Moreover, each one-unit increase in social support was associated with an increased risk of 1-30 days unemployment in individuals older than 45 years and SA and DP. Social support decreased the risk of unemployment longer than 365 days in age groups 16-25 and 36-45 years. In the discordant twin pair analyses, the estimates attenuated towards statistical non-significance.

CONCLUSION

Even though familial factors seem to influence the associations between psychosocial working conditions and LMM, improving psychosocial working conditions by for example promoting high job control and social support at workplace may reduce the risk of future short- and long-term LMM in all age groups.

Investigating the phenotypic and genetic associations between personality traits and suicidal behavior across major mental health diagnoses

Personality traits influence risk for suicidal behavior. We examined phenotype- and genotype-level associations between the Big Five personality traits and suicidal ideation and attempt in major depressive, bipolar and schizoaffective disorder, and schizophrenia patients (N = 3012) using fixed- and random-effects inverse variance-weighted meta-analyses. Suicidal ideations were more likely to be reported by patients with higher neuroticism and lower extraversion phenotypic scores, but showed no significant association with polygenic load for these personality traits. Our findings provide new insights into the association between personality and suicidal behavior across mental illnesses and suggest that the genetic component of personality traits is unlikely to have strong causal effects on suicidal behavior.

Neuromodulation and Individuality

Within populations, individuals show a variety of behavioral preferences, even in the absence of genetic or environmental variability. Neuromodulators affect these idiosyncratic preferences in a wide range of systems, however, the mechanism(s) by which they do so is unclear. I review the evidence supporting three broad mechanisms by which neuromodulators might affect variability in idiosyncratic behavioral preference: by being a source of variability directly upstream of behavior, by affecting the behavioral output of a circuit in a way that masks or accentuates underlying variability in that circuit, and by driving plasticity in circuits leading to either homeostatic convergence toward a given behavior or divergence from a developmental setpoint. I find evidence for each of these mechanisms and propose future directions to further understand the complex interplay between individual variability and neuromodulators.

Maternal personality and alcohol use during pregnancy in Japan: The Tohoku Medical Megabank Project Birth and Three-Generation Cohort Study

BACKGROUND

Studies on associations between maternal personality and alcohol use have examined only one time point during pregnancy in Western countries. We aimed to examine the association between maternal personality and alcohol use in early and middle pregnancy in Japan.

METHODS

We analyzed data from 17,144 pregnant women in Japan who participated in the Tohoku Medical Megabank Project Birth and Three-Generation Cohort Study from 2013 to 2017. Personality was assessed using the short-form Eysenck Personality Questionnaire-Revised. Women were dichotomized as current drinkers or non-drinkers in both early and middle pregnancy. Odds ratios (ORs) and 95% confidence intervals (CIs) for alcohol use in early and middle pregnancy and continued alcohol use between early and middle pregnancy were calculated for 1 standard deviation increase in each personality scale, adjusted for age, as well as education, work status, fertility treatment, and parity.

RESULTS

Higher extraversion scores were associated with alcohol use in early (OR, 1.16; 95% CI, 1.12-1.20) and middle pregnancy (OR, 1.17; 95% CI, 1.10-1.25). Higher psychoticism scores were associated with continued alcohol use into middle pregnancy (OR, 1.07; 95% CI, 1.01-1.14) and alcohol use in middle pregnancy (OR, 1.07; 95% CI, 1.02-1.13). Neuroticism was not associated with alcohol use in early or middle pregnancy. Lower lie was associated with alcohol use in early (OR, 0.95; 95% CI, 0.91-0.98), but not in middle pregnancy.

CONCLUSIONS

Different personality scales are associated with alcohol use at different points during pregnancy.

The roots of paternal depression: Experienced and nonexperienced trauma or Folie a Deux?

The transition to fatherhood may be challenged with anxiety and trepidation. A high prevalence has been found for paternal depression and it is reactive to maternal depression. This review aims to address potential sources of paternal depression, which may have adverse consequences on child development. We describe through three hypotheses how fathers may be at risk of depression during the transition to fatherhood: (1) psychological (interacting with ecological systems); (2) brain functional∖structural changes; and (3) (epi)genomic. We propose that paternal stressful experiences during the transition to fatherhood may be the source for paternal depression through direct stressful paternal experiences or via (potential, currently debated) nonexperienced (by the father) epigenomic transgenerational transmission. On the other hand, we suggest that resilient fathers may undergo a transient dysphoric period affected by identifying with the newborn's vulnerability as well as with the mother's postpartum vulnerability resulting in "paternity blues." In accordance with recent views on paternal "heightened sensitivity" toward the infant, we propose that the identification of both parents with the vulnerability of the newborn creates a sensitive period of Folie a Deux (shared madness) which may be a healthy transient, albeit a quasi-pathological period, recruited by the orienting response of the newborn for survival.

Analysis of Selected Variants of DRD2 and ANKK1 Genes in Combat Athletes

The level of physical activity is conditioned by many different factors, including, among others, the personality traits of a person. Important is the fact that personality traits are a moderately heritable factor and on the basis of the analysis of several genes, various lifetime outcomes can be predicted. One of the most important pathways influencing personality traits is connected to the dopaminergic system; hence, we decided to analyze the DRD2 PROM. rs1799732, DRD2 rs1076560, DRD2 Tag1D rs1800498, DRD2 Ex8 rs6276, DRD2Tag1B rs1079597 and ANKK1 Tag1A rs180049. The research group included 258 male athletes (mean age = 26.02; SD = 8.30), whereas the control group was 284 healthy male volunteers matched for age (mean age = 22.89; SD = 4.78), both of Caucasian origin and without history of substance dependency or psychosis. Genomic DNA was extracted from venous blood using standard procedures. Genotyping was conducted with the real-time PCR method. Differences in the frequency of the DRD2Tag1B rs1079597 gene polymorphism were found between people practicing combat sports and the control group, and the DRD2 PROM. rs1799732, DRD2 rs1076560, DRD2 Tag1D rs1800498, DRD2 Ex8 rs6276, DRD2Tag1B rs1079597 and ANKK1 Tag1A rs1800497 genotypes and allele frequencies in the studied sample did not differ between the analyzed groups. Hence, we considered these polymorphic places as an interesting area for the further search for unambiguous associations between personality traits and attitude towards physical effort.

Taking risks to feel excitement: Detailed personality profile and genetic associations

This study mapped the personality and genetics of risky excitement-seekers focusing on skydiving behavior. We compared 298 skydivers to 298 demographically matched controls across the NEO Personality Inventory-3 domains, facets, and 240 items. The most significant item-level effects were aggregated into a poly-item score of skydiving-associated personality markers (Study 1), where higher scores describe individuals who enjoy risky situations but have no self-control issues. The skydiving-associated personality marker score was associated with greater physical activity, higher rate of traumatic injuries, and better mental health in a sample of 3558 adults (Study 2). From genetic perspective, we associated skydiving behavior with 19 candidate variants that have previously been linked to excitement-seeking (Study 1). Polymorphisms in the SERT gene were the strongest predictors of skydiving, but the false discovery rate-adjusted (FDR-adjusted) p-values were non-significant. In Study 2, we predicted the skydiving-associated personality marker score and E5: Excitement-seeking from multiple risk-taking polygenic scores, using publicly available summary data from genome-wide association studies. While E5: Excitement-seeking was most strongly predicted by general risk tolerance and risky behaviors’ polygenic scores, the skydiving-associated personality marker score was most strongly associated with the adventurousness polygenic scores. Phenotypic and polygenic scores associations suggest that skydiving is a specific—perhaps more functional—form of excitement-seeking, which may nevertheless lead to physical injuries.

"The Heidelberg Five" personality dimensions: Genome-wide associations, polygenic risk for neuroticism, and psychopathology 20 years after assessment

HeiDE is a longitudinal population-based study that started in the 1990s and, at baseline, assessed an array of health-related personality questionnaires in 5133 individuals. Five latent personality dimensions (The Heidelberg Five) were identified and interpreted as Emotional Lability (ELAB), Lack of Behavioral Control (LBCN), Type A Behavior (TYAB), Locus of Control over Disease (LOCC), and Psychoticism (PSYC). At follow-up, 3268 HeiDE participants (post-QC) were genotyped on single nucleotide polymorphism (SNP) arrays. To further characterize The Heidelberg Five, we analyzed genomic underpinnings, their relations to the genetic basis of the Big Five trait Neuroticism, and longitudinal associations with psychiatric symptoms at follow-up. SNP-based heritability was significant for ELAB (34%) and LBCN (29%). A genome-wide association study for each personality dimension was conducted; only the phenotype PSYC yielded a genome-wide significant finding (p < 5 × 10^-8 , top SNP rs138223660). Gene-based analyses identified significant findings for ELAB, TYAB, and PSYC. Polygenic risk scores for Neuroticism were only associated with ELAB. Each of The Heidelberg Five was related to depressive symptoms at follow-up. ELAB, LBCN, and PSYC were also associated with lifetime anxiety symptoms. These results highlight the clinical importance of health-related personality traits and identify LBCN as a heritable "executive function" personality trait.

Maternal personality and postnatal bonding disorder in Japan: the Tohoku Medical Megabank Project Birth and Three-Generation Cohort Study

BACKGROUND

Despite much knowledge of the effects of maternal psychopathology on bonding, the effects of personality have received less attention. We aimed to examine the association between maternal personality and postnatal bonding disorder.

METHODS

We analyzed data from 15,654 women who participated in the Tohoku Medical Megabank Project Birth and Three-Generation Cohort Study. Personality was assessed in middle pregnancy using the short-form Eysenck Personality Questionnaire-Revised, with the score for each subscale categorized into four levels. Bonding disorder was defined as the Mother-to-Infant Bonding Scale score of ≥5 one month after delivery. Multiple logistic regression analyses were conducted to examine the association between personality and bonding disorder after adjusting for age, education, parity, feelings towards pregnancy, social isolation, as well as the Edinburgh Postpartum Depression Scale (EPDS) score.

RESULTS

Higher extraversion was associated with a decreased risk of bonding disorder (p for trend <0.001). Higher neuroticism was associated with an increased risk of bonding disorder (p for trend <0.001), and this association disappeared after further adjustment for EPDS score (p for trend 0.39). No association between psychoticism and bonding disorder was observed (p for trend 0.83), and the association appeared after further adjustment for EPDS score (p for trend 0.0017). Higher lie was associated with a decreased risk of bonding disorder (p for trend <0.001).

LIMITATIONS

Maternal personality and bonding were self-reported.

CONCLUSIONS

Lower extraversion, higher psychoticism, and lower lie were associated with bonding disorder. The association between higher neuroticism and bonding disorder was explained by postnatal depressive symptoms.

Gene-based association analysis identifies 190 genes affecting neuroticism

Neuroticism is a personality trait, which is an important risk factor for psychiatric disorders. Recent genome-wide studies reported about 600 genes potentially influencing neuroticism. Little is known about the mechanisms of their action. Here, we aimed to conduct a more detailed analysis of genes that can regulate the level of neuroticism. Using UK Biobank-based GWAS summary statistics, we performed a gene-based association analysis using four sets of within-gene variants, each set possessing specific protein-coding properties. To guard against the influence of strong GWAS signals outside the gene, we used a specially designed procedure called “polygene pruning”. As a result, we identified 190 genes associated with neuroticism due to the effect of within-gene variants rather than strong GWAS signals outside the gene. Thirty eight of these genes are new. Within all genes identified, we distinguished two slightly overlapping groups obtained from using protein-coding and non-coding variants. Many genes in the former group included potentially pathogenic variants. For some genes in the latter group, we found evidence of pleiotropy with gene expression. Using a bioinformatics analysis, we prioritized the neuroticism genes and showed that the genes that contribute to neuroticism through their within-gene variants are the most appropriate candidate genes.

Personality traits and polymorphisms of genes coding neurotransmitter receptors or transporters: review of single gene and genome-wide association studies

BACKGROUND

The most popular tool used for measuring personality traits is the Five-Factor Model (FFM). It includes neuroticism, extraversion, openness, agreeableness and conscientiousness. Many studies indicated the association of genes encoding neurotransmitter receptors/transporters with personality traits. The relationship connecting polymorphic DNA sequences and FFM features has been described in the case of genes encoding receptors of cannabinoid and dopaminergic systems. Moreover, dopaminergic system receives inputs from other neurotransmitters, like GABAergic or serotoninergic systems.

METHODS

We searched PubMed Central (PMC), Science Direct, Scopus, Cochrane Library, Web of Science and EBSCO databases from their inception to November 19, 2020, to identify original studies, as well as peer-reviewed studies examining the FFM and its association with gene polymorphisms affecting the neurotransmitter functions in central nervous system.

RESULTS

Serotonin neurons modulate dopamine function. In gene encoding serotonin transporter protein, SLC6A4, was found polymorphism, which was correlated with openness to experience (in Sweden population), and high scores of neuroticism and low levels of agreeableness (in Caucasian population). The genome-wide association studies (GWASs) found an association of 5q34-q35, 3p24, 3q13 regions with higher scores of neuroticism, extraversion and agreeableness. However, the results for chromosome 3 regions are inconsistent, which was shown in our review paper.

CONCLUSIONS

GWASs on polymorphisms are being continued in order to determine and further understand the relationship between the changes in DNA and personality traits.

Rostral middle frontal gyrus thickness mediates the relationship between genetic risk and neuroticism trait

Neuroticism is a robust personality trait associated with multiple mental disorders. Heretofore, research on the relationship among genes, brain, and behavior to explore individual differences in neuroticism is scarce. Hence, in this study (N = 630), genetic data, self-reported neuroticism, and brain structural data were combined to explore whether the cortical thickness (CT) of brain regions mediated the relationship between the polygenic risk score (PRS) of neuroticism and NEO neuroticism (NEO-N), and the enrichment analysis was performed to reveal the underlying mechanism of their relationship. Results showed that the PRSs were significantly associated with NEO-N scores (p < .05). The CT of left rostral middle frontal gyrus was negatively related to the best PRS in PRSice (PRS_best ) or the PRS at 0.05 threshold (PRS_0.05 ) (corrected p < .05), which was also found to mediate the association between the PRS and NEO-N (PRS_best : ab = .012, p < .05; PRS_0.05 : ab = .012, p < .05). Enrichment analysis revealed that these genes were mainly involved in biological adhesion, cell adhesion, neuron part, and synapse part, which were associated with the abnormal thickness of frontal cortex. By integrating genetic, brain imaging, and behavioral data, our research initially revealed the neurogenetic underpinnings of neuroticism, which is helpful for understanding individual differences in neuroticism.

The geroscience agenda: Toxic stress, hormetic stress, and the rate of aging

Geroscience offers a counterpoint to the challenged pursuit of curing diseases of aging, by focusing on slowing the biological aging process for extended healthspan earlier in life. Remarkable progress has led this field toward animal trials and the next challenge lies with translation to humans. There is an emerging number of small human trials that can take advantage of new models integrating behavioral and social factors. Understanding dynamic aging mechanisms, given the powerful social determinants of aging (Crimmins, 2020) and human variability and environmental contexts (Moffitt, 2020), will be critical. Behavioral and social factors are intrinsic to aging. Toxic stressors broadly defined can lead to stress-acceleration of aging, either directly impacting aging processes or by shaping poor behavioral health, and underlie the socioeconomic disparities of aging. In contrast, hormetic stressors, acute intermittent stressors of moderate intensity, can produce stress resilience, the ability for quick recovery and possibly rejuvenation of cells and tissues. Although health research usually examines static biomarkers, aging is reflected in dynamic ability to recover from challenges pointing to new interventions and targets for examining mechanisms. A fuller model incorporating stress resilience provides innovative biobehavioral interventions, both for bolstering response to challenges, such as COVID-19, and for improving healthspan.

Migrant adolescents' behavioral problems compared to host adolescents and adolescents in their region of origin: a longitudinal study

BACKGROUND

Since the 1990s, families from the ecologically hostile mountainous southern areas of Ningxia Province, China, have been migrating to the northern areas of the province. This study compared the prevalence of behavioral problems among migrant adolescents to those among host adolescents (adolescents from the northern areas) and adolescents in the region of origin (adolescents from the southern areas), to determine whether ecological migration is related to adolescent behavioral problems, and possible changes in such problems over time.

METHODS

We used the Children and Adolescents Ecological Migration Survey on Mental Health, administered to 4805 students aged 12-16 years and their parents between 2012 and 2014 (W1), of whom 1753 students and their parents completed the follow-up between 2014 and 2017 (W2). Parents answered questions related to adolescent behavioral problems, main source of family income, parents' desire to reverse migrate, improved standard of living, and parents' educational attainment, while children completed the Eysenck Personality Questionnaire and a classroom environment questionnaire.

RESULTS

The prevalence of behavioral problems among the migrant adolescents (28.04%) was significantly higher than among host adolescents (21.59%) or adolescents in the region of origin (24.37%; p < 0.001) at W1. After adjusting for gender and age, parents' work outside the home was the main source of family income (OR = 1.42, 95% CI = 1.13-1.78), and adolescents' learning burden (OR = 1.04, 95% CI = 1.01-1.06) in school negatively influenced behavioral problems. Strong student-teacher relationships (OR = 0.97,95% CI = 0.94-0.99) and parents who had no intention to move back to the original residence (OR = 0.70, 95% CI = 0.52-0.94) exerted a protective effect at W1; at W2, a protective effect was associated with improved living conditions (OR = 0.39-0.55, 95% CI = 0.25-0.84). The extent of behavioral problems among migrant adolescents significantly decreased after two years.

CONCLUSION

Ecological migration will increase children's behavioral problems in the early stage, with various factors influencing the extent of these problems.

Multiscale neurobiological correlates of human neuroticism

Neuroticism is a heritable personality trait associated with negative emotionality; however, we know little regarding the association between the microscale and macroscale neurobiological substrates of human neuroticism. Cross‐scale correlation analysis may provide such information. In this study, voxel‐wise neuroimaging–neuroticism correlation analyses consistently showed a positive correlation between neuroticism and functional connectivity density (FCD) in the ventral striatum in 274 young Chinese adults. Partial least squares regression analysis showed that the FCD‐neuroticism correlation map was significantly spatially correlated with gene expression profiles in each of six donated human brains. Neuroticism‐related genes derived from the six donors consistently showed significant enrichment in the chemical synaptic transmission, circadian entrainment, long‐term potentiation, inflammatory mediator regulation of transient receptor potential channels, and amphetamine addiction pathways. The protein–protein interaction analysis revealed four hub genes involved in the above pathways, including G protein subunit gamma 10, 5‐hydroxytryptamine receptor 2C, prodynorphin, and calcium/calmodulin‐dependent protein kinase II alpha. By combining multiscale correlation analyses and functional annotations, this study advances our understanding of the genetic and neural substrates of human neuroticism and emphasizes the importance of striatal functional properties in human neuroticism.

Behavioral-genetic associations in the Human Connectome Project

The Human Connectome Project (HCP) provides a rich dataset of quantitative and domain-specific behavioral measures from twins and extensive family structures. This makes the dataset a unique and a valuable resource to investigate heritability and determine individual differences. Using a set of measures of behavioral domains (motor, emotion, personality, sensory, and cognition), we estimated the intraclass correlations (ICCs) and heritability of 56 behavioral measures for 4 genetically identified groups of participants: monozygotic (MZ) twins, dizygotic (DZ) twins, non-twin siblings (SB), and unrelated individuals (NR). The ICCs range varied among behavioral domains but systematically so among the four genetic groups. We found the same rank order of ICCs, from the highest values for MZ twins, statistically significantly smaller for the DZ twins and sibling group (compared to MZ), and close to zero for NR. The mean heritability values of the five behavioral domains were: cognition h² = 0.405, emotion h² = 0.316, motor h² = 0.138, personality h² = 0.444, and sensory h² = 0.193. These domains share overlapping brain networks. The heritability of motor domain was significantly smaller than cognitive, personality, and emotion domains. These findings provide new insight into the effect of genetics on the various diverse behavioral measures.

Genetic and environmental variation in educational attainment: an individual-based analysis of 28 twin cohorts

We investigated the heritability of educational attainment and how it differed between birth cohorts and cultural-geographic regions. A classical twin design was applied to pooled data from 28 cohorts representing 16 countries and including 193,518 twins with information on educational attainment at 25 years of age or older. Genetic factors explained the major part of individual differences in educational attainment (heritability: a2 = 0.43; 0.41-0.44), but also environmental variation shared by co-twins was substantial (c2 = 0.31; 0.30-0.33). The proportions of educational variation explained by genetic and shared environmental factors did not differ between Europe, North America and Australia, and East Asia. When restricted to twins 30 years or older to confirm finalized education, the heritability was higher in the older cohorts born in 1900-1949 (a2 = 0.44; 0.41-0.46) than in the later cohorts born in 1950-1989 (a2 = 0.38; 0.36-0.40), with a corresponding lower influence of common environmental factors (c2 = 0.31; 0.29-0.33 and c2 = 0.34; 0.32-0.36, respectively). In conclusion, both genetic and environmental factors shared by co-twins have an important influence on individual differences in educational attainment. The effect of genetic factors on educational attainment has decreased from the cohorts born before to those born after the 1950s.