Life Events as Environmental States and Genetic Traits and the Role of Personality: A Longitudinal Twin Study

Gene-environment interaction study on the polygenic risk score for neuroticism, childhood adversity, and parental bonding

The present study examines whether neuroticism is predicted by genetic vulnerability, summarized as polygenic risk score for neuroticism (PRSN), in interaction with bullying, parental bonding, and childhood adversity. Data were derived from a general population adolescent and young adult twin cohort. The final sample consisted of 202 monozygotic and 436 dizygotic twins and 319 twin pairs. The Short Eysenck Personality questionnaire was used to measure neuroticism. PRSN was trained on the results from the Genetics of Personality Consortium (GPC) and United Kingdom Biobank (UKB) cohorts, yielding two different PRSN. Multilevel mixed-effects models were used to analyze the main and interacting associations of PRSN, childhood adversity, bullying, and parental bonding style with neuroticism. We found no evidence of gene-environment correlation. PRSN thresholds of .005 and .2 were chosen, based on GPC and UKB datasets, respectively. After correction for confounders, all the individual variables were associated with the expression of neuroticism: both PRSN from GPC and UKB, childhood adversity, maternal bonding, paternal bonding, and bullying in primary school and secondary school. However, the results indicated no evidence for gene-environment interaction in this cohort. These results suggest that genetic vulnerability on the one hand and negative life events (childhood adversity and bullying) and positive life events (optimal parental bonding) on the other represent noninteracting pathways to neuroticism.

Examining individual differences in personality trait changes after negative life events

Personality traits can change throughout the entire life span, but people differ in their personality trait changes. To better understand individual differences in personality changes, we examined personal (personality functioning), environmental (environmental changes), and event-related moderators (e.g., perceived event characteristics) of personality trait changes. Therefore, we used a sample of 1069 participants who experienced a negative life event in the last 5 weeks and assessed their personality traits at five measurement occasions over 6 months. Employing preregistered multilevel lasso estimation, we did not find any significant effects. While exploratory analyses generally confirmed this conclusion, they also identified some effects that might being worth to be considered in future research (e.g., perceived impact and perceived social status changes were associated with changes in agreeableness after experiencing a relationship breakup). In total, our moderators explained less than 2% of variance in personality traits. Nonetheless, our study has several important implications for future research on individual differences in personality change. For example, future research should consider personal, environmental, and event-related moderators, use different analytical methods, and rely on highly powered samples to detect very small effects.

The evolution of personality disorders: A review of proposals

Personality disorders (PDs) are currently considered dysfunctions. However, personality differences are older than humanity and are ubiquitous in nature, from insects to higher primates. This suggests that a number of evolutionary mechanisms-other than dysfunctions-may be able to maintain stable behavioral variation in the gene pool. First of all, apparently maladaptive traits may actually improve fitness by enabling better survival or successful mating or reproduction, as exemplified by neuroticism, psychopathy, and narcissism. Furthermore, some PDs may harm important biological goals while facilitating others, or may be globally beneficial or detrimental depending on environmental circumstances or body condition. Alternatively, certain traits may form part of life history strategies: Coordinated suites of morphological, physiological and behavioral characters that optimize fitness through alternative routes and respond to selection as a whole. Still others may be vestigial adaptations that are no longer beneficial in present times. Finally, variation may be adaptative in and by itself, as it reduces competition for finite resources. These and other evolutionary mechanisms are reviewed and illustrated through human and non-human examples. Evolutionary theory is the best-substantiated explanatory framework across the life sciences, and may shed light on the question of why harmful personalities exist at all.

The Stressful Personality: A Meta-Analytical Review of the Relation Between Personality and Stress

The current study presented the first meta-analytic review on the associations between the Big Five personality traits and stress measured under different conceptualizations (stressor exposure, psychological and physiological stress responses) using a total of 1,575 effect sizes drawn from 298 samples. Overall, neuroticism was found to be positively related to stress, whereas extraversion, agreeableness, conscientiousness, and openness were negatively linked to stress. When stress assessed under different conceptualizations was tested, only neuroticism, agreeableness, and conscientiousness were related to stressor exposure. All of the Big Five personality traits were significantly associated with psychological stress perception, whereas the five personality traits showed weak to null associations with physiological stress response. Further moderation analyses suggested that the associations between personality traits and stress under different conceptualizations were also contingent upon different characteristics of stress, sample, study design, and measures. The results supported the important role of personality traits in individual differences in stress.

Perception of major life events and personality trait change

Major life events can trigger personality trait change. However, a clear, replicable pattern of event-related personality trait change has yet to be identified. We examined whether the perception of major life events is associated with personality trait change. Therefore, we assessed young adults’ personality traits at five measurement occasions within 1 year. At the second measurement occasion, we also assessed their perception of a recently experienced major life event using the Event Characteristics Questionnaire. Contrary to our expectations, perceived impact of the event was not associated with the amount of personality trait change, but perceived valence was associated with changes in agreeableness and neuroticism. Exploratory analyses revealed some weak associations between other perceived event characteristics and the amount of personality trait change as well as interactions between perceived event characteristics and event categories in predicting changes in neuroticism. In general, effect sizes were small, and associations depended on the time interval between pre-event and post-event personality assessment. Results indicate that perceived event characteristics should be considered when examining event-related personality trait change.

Conceptualizing and Studying Characteristics, Units, and Fits of Persons and Environments: A Coherent Synthesis

Based on a perspective on personality coherence as the extent to which personality-relevant characteristics are differentiated and integrated within a person in his or her environment, we propose a synthesis that builds on and harmonizes existing and partly conflicting theories, methodological approaches, and empirical findings. This understanding of personality coherence needs clear definitions of person and environment characteristics. We define traits as characteristics of the person, adaptations as characteristics of the person-in-contexts, and states as characteristics of the person-in-situations. Thus, our synthesis involves concepts of environments and person-environment units. Next, we provide testable criteria to differentiate characteristics of persons from characteristics of person-environment units and to identify dispositional traits for a narrow-sense perspective on personality coherence. We raise awareness of the importance of fit between (profiles of) person and environment characteristics for an understanding of the integrated uniqueness of persons in their environments. We outline implications of this broader perspective on personality coherence for personality development, self-regulation, social integration, well-being, and psychological interventions. Lastly, we conclude that the analysis of an individual’s uniqueness and personality differences requires information about how well-defined, well-differentiated, well-integrated, and well-operationalized person(ality) variables are actually expressed in, or interact and transact with, the individual environment.

Personality Traits and Perceptions of Major Life Events

Research examining the associations between major life events and personality trait development is mixed. Work that evaluates perceptions of life events and how those perceptions are themselves associated with personality traits may help clarify the existing literature. We used a large student sample ( N = 1,509) and a demographically diverse sample from a Qualtrics panel ( N = 552) to conduct exploratory analyses examining the associations between the big five personality traits and perceptions of life events. Results suggested that (a) associations between personality and beliefs about event-related personality change differ between students and more representative samples, (b) associations between personality and event perceptions are often nuanced, and (c) event perceptions are not merely proxies for personality traits. These studies highlight the importance of subjective event perceptions in the study of major life events and personality.

Perceived Characteristics of Life Events—Short-Term Changes in Prosociality and Empathy?

Post-traumatic growth can be understood as positive change in desirable personality traits after adverse life events. However, recent research questioned whether adversity is a relevant, necessary, and sufficient condition for change in desirable personality traits. Using five-wave longitudinal data, this study explored changes in the desirable personality traits prosociality and empathy before and after life events. We included all life events participants had experienced between the second and third assessment, that is, adverse, ambiguous, and positive events. Participants rated their life events on the Event Characteristics Questionnaire which assesses the individual perception of life events on nine continuous dimensions: challenge, emotional significance, extraordinariness, external control, impact, valence, social status change, predictability, and change in world views. We used multilevel growth curve models to explore changes in prosociality and empathy as a function of these event characteristics. Prosociality and empathy remained stable in the assessment period of 6 to 9 months after the reported life event, independently of whether the event had been perceived as adverse or not. We discuss our findings with respect to the inclusion of positive and ambiguous events as predictors of personality change and with respect to its theoretical implications for post-traumatic growth and personality development more broadly.

A multilevel examination of lifetime aggression: integrating cortical thickness, personality pathology and trauma exposure

Aggression represents a significant public health concern, causing serious physical and psychological harm. Although many studies have sought to characterize the etiology of aggression, research on the contributions of risk factors that span multiple levels of analysis for explaining aggressive behavior is lacking. To address this gap, we investigated the direct and unique contributions of cortical thickness (level 1), pathological personality traits (level 2) and trauma exposure (level 3) for explaining lifetime physical aggression in a high-risk sample of community adults (N = 129, 47.3% men). First, the frequency of lifetime aggression was inversely associated with cortical thickness in regions of prefrontal and temporal cortices that have been implicated in executive functioning, inhibitory mechanisms and socio-emotional processing. Further, aggression was positively associated with pathological personality traits (antagonism and disinhibition) and exposure to assaultive trauma. Notably, all three levels of analysis (cortical thickness, pathological personality traits and assaultive trauma exposure) explained non-overlapping variance in aggressive behavior when examined simultaneously in integrative models. Together, the findings provide a multilevel assessment of the biopsychosocial factors associated with the frequency of aggression. They also indicate that cortical thickness explains novel variance in these harmful behaviors not captured by well-established personality and environmental risk factors for aggression.

Growth all along the road? Personality development and international contacts of (in)experienced sojourners

International student mobility (ISM) is an important educational means to promote the international (job market) potential of university students. Beyond that, it constitutes a context of personality development in young adulthood. With the present research, we tried to integrate the perspectives of applied and personality research in addressing the following questions. First, we scrutinized the robustness of ISM effects on personality development as we controlled for effects of sociodemographic characteristics and implemented a waiting group design ( N = 3070). Second, we explored ISM anticipation effects as well as the moderation of ISM effects by previous international mobility experiences. Finally, in view of the public discourse on the benefits of “Erasmus crowds”, we assessed the roles of international and host relationships with regard to the personality development of sojourners. The results largely corroborated the robustness of ISM effects on personality development. No ISM anticipation effects occurred, and effects of current ISM engagement were largely unaffected by previous international mobility experiences. Finally, international contact experiences were associated with personality development above and beyond effects of host country contacts. Implications for the understanding of personality development and potential inferences for the organization and improvement of ISM programs are discussed.

The impact of family violence incidents on personality changes: An examination of social media users' messages in China

Changes in personality tend to be intertwined with life events (e.g., family violence [FV]). This study aimed to examine the personality changes before and after an FV incident using Weibo data. Samples were selected from 1.16 million Weibo users in China who had posted their own FV experience as victims. We used Linguistic Inquiry and Word Count (LIWC) to extract the linguistic features of these unstructured texts as the scores of participants' personality. We built prediction models to measure and compare personality differences between the victim group and control group in Sample 1; and personality changes between the victim group and control group before and after an FV incident in Sample 2. Results showed that the victims' neuroticism increased and conscientiousness decreased after experiencing FV. At the same time, their agreeableness and openness levels were lower than those of the control group. Implications and limitations are also discussed.

The Differential Heritability of Social Adjustment by Sex

Sex differences in social adjustment are frequently observed; however, there has been very little research on adaptability in the individual and social domains. The aim of this study was to investigate the sex difference in social abilities, such as high self-appeal, sociability, school adaptation, and home adaptation between school-age males and females. The sample for this study included both same-sex and opposite-sex twin pairs: a total of 467 twin pairs. We classified them into three groups: a group of those in lower classes of elementary school, a group of those in higher classes of elementary school, and a group of those in junior high school. The heritability of school adaptation was estimated to be 95% in males and 54% in females in the junior high school group. The full sex-limitation model showed a better fit in this group, and this means that a qualitative genetic difference exists. For school adaptation, there was no sex difference in lower elementary school classes; however, a quantitative difference appeared in higher classes of elementary school. Moreover, a qualitative difference appeared in junior high school. From this research, it became clear that sex differences in heritability exist for school adaptation, and there was a marked increase from the elementary school children to the junior high school children.

Changes in optimism and pessimism in response to life events: Evidence from three large panel studies

Although individuals vary in how optimistic they are about the future, one assumption that researchers make is that optimism is sensitive to changes in life events and circumstances. We examined how optimism and pessimism changed across the lifespan and in response to life events in three large panel studies (combined N = 74,886). In the American and Dutch samples, we found that optimism increased across younger adulthood, plateaued in midlife, and then decreased in older adulthood. In the German sample, there were inconsistent results with respect to age differences and mean level changes in optimism. Associations between life events and changes in optimism/pessimism were inconsistent across samples. We discuss our results in the context of life events and lifespan development.

Personality traits change after an opportunity to mate

There is growing evidence that personality traits can change throughout the life course in humans and nonhuman animals. However, the proximate and ultimate causes of personality trait change are largely unknown, especially in adults. In a controlled, longitudinal experiment, we tested whether a key life event for adults--mating--can cause personality traits to change in female threespine sticklebacks. We confirmed that there are consistent individual differences in activity, sociability and risk-taking, and then compared these personality traits among three groups of females: (i) control females; (ii) females that had physically mated, and (iii) females that had socially experienced courtship but did not mate. Both the physical experience of mating and the social experience of courtship caused females to become less willing to take risks and less social. To understand the proximate mechanisms underlying these changes, we measured levels of excreted steroids. Both the physical experience of mating and the social experience of courtship caused levels of dihydroxyprogesterone (17α,20β-P) to increase, and females with higher 17α,20β-P were less willing to take risks and less social. These results provide experimental evidence that personality traits and their underlying neuroendocrine correlates are influenced by formative social and life-history experiences well into adulthood.

Longitudinal Experience–Wide Association Studies—A Framework for Studying Personality Change

The importance of personality for predicting life outcomes in the domains of love, work, and health is well established, as is evidence that personality traits, while relatively stable, can change. However, little is known about the sources and processes that drive changes in personality traits and how such changes might impact important life outcomes. In this paper, we make the case that the research paradigms and methodological approaches commonly used in personality psychology need to be revised to advance our understanding of the sources and processes of personality change. We propose Longitudinal Experience–Wide Association Studies as a framework for studying personality change that can address the limitations of current methods, and we discuss strategies for overcoming some of the challenges associated with Longitudinal Experience–Wide Association Studies. © 2020 European Association of Personality Psychology

The reciprocal impacts of adversity and personality traits: A prospective longitudinal study of growth, change, and the power of personality

OBJECTIVE

We integrate the study of post-traumatic growth with personality science by examining the reciprocal effects of adversity and core personality traits. We implemented conceptual (i.e., incorporating personality traits into the study of adversity-related growth, examining trait-specific and configural personality change, and adopting a cumulative approach to adversity) and methodological (i.e., three-wave prospective design, assessing many life events, sampling from populations likely to experience adversity) innovations to advance the study of personality development and of the generality of adversity-related growth.

METHOD

A diverse sample (41% nonwhite, 48% low-income, 68% female, M_age  = 44, 30% diagnosed with Borderline Personality Disorder) participated in a three-wave prospective longitudinal study (N = 258-128 across waves). Participants completed a personality inventory and a battery of life-event surveys (including 105 events) at each wave.

RESULTS

Personality was generally stable from trait-specific and configural perspectives, and all traits were correlated with adversity. All traits, particularly Extraversion and Conscientiousness, predicted adversity. Adversity predicted increases in Emotionality and decreases in Agreeableness.

CONCLUSIONS

Although personality growth is not the typical response to adversity within a 3-year period, findings underscore the real-world impact of personality, and they provide some support for developmental theories emphasizing the effects of life events.

The interplay of personality and attitudes toward own aging across two decades of later life

Big Five personality traits are assumed to be linked with attitudes toward own aging. Since both constructs have central importance for the aging process, it is surprising that to our knowledge no study so far comprehensively addressed their mutual connection over time. We used data from the ILSE study, a longitudinal study capturing personality and attitudes toward own aging at four measurement occasions, spanning 20 years and including two participant cohorts in midlife (n = 501; born 1950-52) and later life (n = 500; born 1930-32). Dual latent change score models showed that personality was longitudinally related to change in attitudes toward own aging: Lower Neuroticism, higher Conscientiousness, and higher Openness predicted more positive attitudes, whereas the direction of the effect for Extraversion varied by time. Furthermore, the role of personality seems to be confined to certain sensitive periods in midlife and early old age. Contrary to our expectations, attitudes toward own aging had only marginal longitudinal impact on the Big Five. Our results shed light on the developmental co-dynamics of personality and subjective perceptions of aging across the second half of the lifespan.

The E Is in the G: Gene-Environment-Trait Correlations and Findings From Genome-Wide Association Studies

Genome-wide association studies (GWASs) have shown that pleiotropy is widespread (i.e., the same genetic variants affect multiple traits) and that complex traits are polygenic (i.e., affected by many genetic variants with very small effect sizes). However, despite the growing number of GWASs, the possible contribution of gene-environment correlations (rGEs) to pleiotropy and polygenicity has been mostly ignored. rGEs can lead to environmentally mediated pleiotropy or gene-environment-trait correlations (rGETs), given that an environment that is affected by one genetically influenced phenotype, can in turn affect a different phenotype. By adding correlations with environmentally mediated genetic variants, rGETs can contribute to polygenicity. Socioeconomic status (SES) and the experience of stressful life events may, for example, be involved in rGETs. Both are genetically influenced and have been associated with a myriad of physical and mental disorders. As a result, GWASs of these disorders may find the genetic correlates of SES and stressful life events. Consequently, some of the genetic correlates of physical and mental disorders may be modified by public policy that affects environments such as SES and stressful life events. Thus, identifying rGETs can shed light on findings from GWASs and have important implications for public health.

Personality Change in Middle Adulthood: With Focus on Differential Susceptibility

Little attention has been paid to middle adulthood in research on personality stability and change. In addition, previous research on individual differences in personality change has not fully explained its variability. This study focused on the differential susceptibility model, which suggests that individual susceptibility interacts with environmental factors and produces variability in outcomes, and investigated individual differences in personality change with a middle adult sample. A total of 1051 Japanese middle adults (M = 41.61 years; SD = 5.31; range 30-50 years; 534 females) participated in this two-wave short-term longitudinal study. Latent change score model analyses revealed substantial mean-level declines in Agreeableness and Honesty-Humility. Moreover, the results showed that the influences of some life events on personality change are moderated for better and for worse by individual susceptibility to one's environment. These findings suggest that the trends of personality development may differ between Western and non-Western countries and that differential susceptibility model may play an important role in deriving individual differences in personality stability and change.

Genome-wide by environment interaction studies of depressive symptoms and psychosocial stress in UK Biobank and Generation Scotland

Stress is associated with poorer physical and mental health. To improve our understanding of this link, we performed genome-wide association studies (GWAS) of depressive symptoms and genome-wide by environment interaction studies (GWEIS) of depressive symptoms and stressful life events (SLE) in two UK population-based cohorts (Generation Scotland and UK Biobank). No SNP was individually significant in either GWAS, but gene-based tests identified six genes associated with depressive symptoms in UK Biobank (DCC, ACSS3, DRD2, STAG1, FOXP2 and KYNU; p < 2.77 × 10-6). Two SNPs with genome-wide significant GxE effects were identified by GWEIS in Generation Scotland: rs12789145 (53-kb downstream PIWIL4; p = 4.95 × 10-9; total SLE) and rs17070072 (intronic to ZCCHC2; p = 1.46 × 10-8; dependent SLE). A third locus upstream CYLC2 (rs12000047 and rs12005200, p < 2.00 × 10-8; dependent SLE) when the joint effect of the SNP main and GxE effects was considered. GWEIS gene-based tests identified: MTNR1B with GxE effect with dependent SLE in Generation Scotland; and PHF2 with the joint effect in UK Biobank (p < 2.77 × 10-6). Polygenic risk scores (PRSs) analyses incorporating GxE effects improved the prediction of depressive symptom scores, when using weights derived from either the UK Biobank GWAS of depressive symptoms (p = 0.01) or the PGC GWAS of major depressive disorder (p = 5.91 × 10-3). Using an independent sample, PRS derived using GWEIS GxE effects provided evidence of shared aetiologies between depressive symptoms and schizotypal personality, heart disease and COPD. Further such studies are required and may result in improved treatments for depression and other stress-related conditions.

Development of Self-Directedness and Cooperativeness in Relation to Post-Traumatic Stress Disorder Symptom Trajectories After Military Deployment

Background

Personality traits, such as the character traits self-directedness and cooperativeness, might play a role in the risk of developing post-traumatic stress disorder (PTSD) after deployment to a combat zone. However, it is unclear whether these traits are preexisting risk factors or if event-related changes might also be associated with PTSD symptoms over time. Therefore, the current aim was to assess if military deployment is associated with changes in cooperativeness and self-directedness and to study how these traits are related to PTSD symptom trajectories.

Methods

In a large cohort of military personnel (N = 1007), measurements were performed before, at one and six months, and two and five years after deployment to Afghanistan. Linear mixed-effect models were used to assess the individual change in the traits over time and to study the relation with potential predictors.

Results

Cooperativeness was found to remain stable, whereas self-directedness was found to slightly decrease over time. This decrease was related to the development of PTSD symptoms over time. Furthermore, lower levels of self-directedness were associated with the symptomatic trajectories of PTSD symptoms. Lower levels of cooperativeness were only associated with the recovered PTSD trajectory.

Conclusions

So, not only do the findings confirm that lower levels of these character traits are associated with the development of PTSD symptoms, it was also shown that there are differences in the relation between these traits and the course of PTSD symptoms. Studying methods to promote the levels of these character traits might help to improve the resiliency of military personnel.

Sequences of maladaptation: Preadolescent self-regulation, adolescent negative social interactions, and young adult psychopathology

This study aims to test whether adolescent negative social interactions mediate the relation between early adolescent self-regulatory capacities and young adult psychopathology, using a fully prospective mediation model. Data were derived from the Tracking Adolescents' Individual Lives Survey, a large population cohort of Dutch adolescents (n = 962). At age 11, three indicators of self-regulation were assessed: low frustration, high effortful control, and high response inhibition. Negative social interactions between ages 11 and 22 were captured twice using the Event History Calendar. Psychopathology (i.e., internalizing and externalizing problems) was assessed at ages 11 and 22. Findings indicate that adolescents' frustration and effortful control but not response inhibition assessed at age 11 are related to both internalizing and externalizing problems at age 22, after controlling for psychopathology at age 11, sex, and socioeconomic status. These associations were partly (about 22%) mediated by the negative social interactions adolescents experienced. Effect sizes were all modest. This study shows that self-regulation is related to subsequent psychopathology in part through its effect on negative social interactions, providing evidence for sequences of self-regulatory capacities, life experiences, and developmental outcomes.

Monoamine Oxidase A (MAOA) Gene and Personality Traits from Late Adolescence through Early Adulthood: A Latent Variable Investigation

Very few molecular genetic studies of personality traits have used longitudinal phenotypic data, therefore molecular basis for developmental change and stability of personality remains to be explored. We examined the role of the monoamine oxidase A gene (MAOA) on extraversion and neuroticism from adolescence to adulthood, using modern latent variable methods. A sample of 1,160 male and 1,180 female participants with complete genotyping data was drawn from a British national birth cohort, the MRC National Survey of Health and Development (NSHD). The predictor variable was based on a latent variable representing genetic variations of the MAOA gene measured by three SNPs (rs3788862, rs5906957, and rs979606). Latent phenotype variables were constructed using psychometric methods to represent cross-sectional and longitudinal phenotypes of extraversion and neuroticism measured at ages 16 and 26. In males, the MAOA genetic latent variable (AAG) was associated with lower extraversion score at age 16 (β = −0.167; CI: −0.289, −0.045; p = 0.007, FDRp = 0.042), as well as greater increase in extraversion score from 16 to 26 years (β = 0.197; CI: 0.067, 0.328; p = 0.003, FDRp = 0.036). No genetic association was found for neuroticism after adjustment for multiple testing. Although, we did not find statistically significant associations after multiple testing correction in females, this result needs to be interpreted with caution due to issues related to x-inactivation in females. The latent variable method is an effective way of modeling phenotype- and genetic-based variances and may therefore improve the methodology of molecular genetic studies of complex psychological traits.

Genetic and Environmental Pathways Underlying Personality Traits and Perceived Stress: Concurrent and Longitudinal Twin Studies

The present study examined the genetic and environmental etiology underlying the Big Five personality traits and perceived stress, concurrently and longitudinally. In study 1, we used the twin sample from the National Longitudinal Study of Adolescent to Adult Health (Add Health IV) data. The results indicated that about 70% of the association between the Big Five personality traits and perceived stress was due to genetic influences. In study 2, we used the twin sample from the Midlife in the United States Survey (MIDUS I and II) to examine the genetic and environmental influences underlying the longitudinal relations between the Big Five personality traits and perceived stress. The results suggested that continuity in perceived stress was primarily accounted for by genetic influences, and changes in perceived stress were mainly due to nonshared environmental influences. The continuity in the association between the five personality traits and perceived stress was largely accounted for by genetic factors, and nonshared environmental factors made greater contributions to changes in the association between personality traits and perceived stress. Among the Big Five personality traits, the genetic components in conscientiousness and neuroticism made substantial contributions to the genetic link between personality traits and perceived stress across both studies.

Does stress play a significant role in bipolar disorder? A meta-analysis

BACKGROUND

There is evidence that stressful life events (LE) play a crucial role in the etiology of bipolar affective disorder (BD). However, primary studies, as well as narrative reviews, have provided mixed results. The present meta-analysis combined and analyzed previous data in order to address these inconsistencies.

METHOD

Forty-two studies published in 53 records were identified by systematically searching MEDLINE, PsychINFO, and PSYCHINDEX using the terms "bipolar disorder" OR "manic-depressive" OR "bipolar affective disorder" OR "mania" AND "stress" OR "life event" OR "daily hassles" OR "goal attainment". Then, meta-analyses were conducted.

RESULTS

Individuals diagnosed with BD reported more LE before relapse when compared to euthymic phases. They also experienced more LE relative to healthy individuals and to physically ill patients. No significant difference in the number of LE was found when BD was compared to unipolar depression and schizophrenia.

LIMITATIONS

When interpreting the present meta-analytic findings one should keep in mind that most included studies were retrospective and often did not specify relevant information, e.g., if the LE were chronic or acute or if the individuals were diagnosed with BD I or II. We could not entirely rule out a publication bias.

CONCLUSION

The present meta-analyses found that individuals with BD were sensitive to LE, which corroborates recent theoretical models and psychosocial treatment approaches of BD. Childbirth, as a specific LE, affected individuals with BD more than individuals with unipolar depression. Future studies that investigate specific LE are warranted.

Life Events and Personality Trait Change

OBJECTIVE

Theory and research have emphasized the impact of life events on personality trait change. In this article, we review prospective research on personality trait change in response to nine major life events in the broader domains of love and work.

METHOD

We expected to find that life events lead to personality trait change to the extent that they have a lasting influence on individuals' thoughts, feelings, and behavior. Moreover, we predicted that love-related life events such as marriage or parenthood would be more strongly related to changes in traits that emphasize affective content, whereas work-related life events would be more likely to lead to change in traits that reflect behavioral or cognitive content.

RESULTS

The current state of research provided some evidence that life events can lead to changes in personality traits and that different life events may be differently related to specific trait domains.

CONCLUSIONS

A more general conclusion emerging from this review is that the evidence for the nature, shape, and timing of personality trait change in response to life events is still preliminary. We discuss the implications of the results for theory and research and provide directions for future studies on life events and personality trait change.

The effect of childhood trauma and Five-Factor Model personality traits on exposure to adult life events in patients with psychotic disorders

INTRODUCTION

Recent life events are associated with transition to and outcome in psychosis. Childhood trauma and personality characteristics play a role in proneness to adult life events. However, little is known about the relative contribution and interrelatedness of these characteristics in psychotic disorders. Therefore, we investigated whether Five-Factor Model (FFM) personality traits and childhood trauma (abuse and neglect) predict adult life events, and whether the effect of childhood trauma on life events is mediated by personality traits.

METHOD

One hundred and sixty-three patients with psychotic disorders were assessed at baseline on history of childhood maltreatment and FFM personality traits, and on recent life events at 3-year follow-up.

RESULTS

Childhood abuse is associated with negative life events, and part of the effect of childhood abuse on negative life events is mediated by openness to experience. Openness to experience and extraversion are associated with more positive and negative life events. Childhood neglect and lower extraversion are related to experiencing less positive events.

CONCLUSION

The association between childhood trauma and recent life events is partly mediated by personality. Future research could focus on mechanisms leading to positive life events, as positive life events may buffer against development of mental health problems.

How temperament and character affect our career, relationships, and mental health

BACKGROUND

On the way toward an agreed dimensional taxonomy for personality disorders (PD), several pivotal questions remain unresolved. We need to know which dimensions produce problems and in what domains of life; whether impairment can be found at one or both extremes of each dimension; and whether, as is increasingly advocated, some dimensions measure personality functioning whereas others reflect style.

METHOD

To gain this understanding, we administered the Temperament and Character Inventory to a sample of 862 consecutively attended outpatients, mainly with PDs (61.2%). Using regression analysis, we examined the ability of personality to predict 39 variables from the Life Outcome Questionnaire concerning career, relationships, and mental health.

RESULTS

Persistence stood out as the most important dimension regarding career success, with 24.2% of explained variance on average. Self-directedness was the best predictor of social functioning (21.1%), and harm avoidance regarding clinical problems (34.2%). Interpersonal dimensions such as reward dependence and cooperativeness were mostly inconsequential. In general, dimensions were detrimental only in one of their poles.

CONCLUSIONS

Although personality explains 9.4% of life problems overall, dimensions believed to measure functioning (character) were not better predictors than those measuring style (temperament). The notion that PD diagnoses can be built upon the concept of "personality functioning" is unsupported.

Victimization and psychopathic features in a population-based sample of Finnish adolescents

We examined different forms of victimization experiences in relation to psychopathic features and whether these associations differed in boys and girls among 4855 Finnish school adolescents aged 15-16 years. Psychopathic features were measured with the Antisocial Process Screening Device- Self Report (APSD-SR). Victimization was assessed with questions about violent and abusive experiences across lifetime and within the last 12 months. Results from linear regression analysis showed that victimization was significantly associated with higher APSD-SR total scores, more strongly in girls than boys. Recent (12-month) victimization showed significance in the relationship between victimization and psychopathic features; especially recent sexual abuse and parental corporal punishment were strong determinants of higher APSD-SR total scores. The present study demonstrates novel findings on how severe victimization experiences relate to psychopathic features in community youth, especially in girls. The findings underscore the need for comprehensive evaluation of victimization experiences when psychopathic features are present in youth.

Additive and Synergetic Contributions of Neuroticism and Life Events to Depression and Anxiety in Women

In this genetically informative and longitudinal study of women, we investigated the nature of individual differences in tendencies to depression (TD) and anxiety (TA) as well as in the probability to develop unipolar mood disorders (UMDs), anxiety disorders (ADs) or both. Specifically, we examined the roles of neuroticism, negative and positive life events and their interplay as heritable and environmental factors of variance in TD and TA. Cross–sectional data from a total of 1200 women including 232 patients (suffering from UMDs and/or ADs) and longitudinal data from 630 female twins including 260 complete pairs were analysed. The analyses yielded that variance in neuroticism mediated the vast majority of the genetic variance in both TD (about 85–90%) and TA (about 70–75%). Negative life events additionally contributed as risk factors accounting for common and specific environmental variance in both TD and TA, whereas positive life events only acted as protective factors in the case of TD. Moreover, TD but not TA was associated with both the probability of exposure and the sensitivity to negative life events and a negative life–event balance (i.e. more negative than positive experiences). The results were discussed within the framework of additive, dynamic and synergetic diathesis–stress models. Copyright © 2016 European Association of Personality Psychology

The Development of Self-Criticism and Dependency in Early Adolescence and Their Role in the Development of Depressive and Anxiety Symptoms

According to Blatt and others (e.g., A. T. Beck), self-definition, or one’s sense of self, and one’s sense of relatedness to others represent core lifespan developmental tasks. This study examined the role of events pertaining to self-definition or relatedness in the development of personality traits from each domain (self-criticism and dependency), and their relationship to the development of depressive and anxiety symptoms. Two hundred seventy-six early adolescents completed a measure of self-criticism and dependency at baseline and again 24 months later, along with measures of depressive and anxiety symptoms. Every 3 months, participants completed a measure of life events, which were coded as self-definitional or relatedness oriented (80% rater agreement, kappa = .70). Structural equation models showed that self-definitional events predicted increases in self-criticism, which in turn predicted increases in depressive symptoms, whereas relatedness events predicted increases in dependency, although dependency was unrelated to change in symptoms.

Principles of Situation Research: Towards a Better Understanding of Psychological Situations

There is currently no consensus on how to study psychological situations, and situation research is still riddled with problems of conceptualization (what is a situation and what is it not?) and measurement (how can situational information be assessed?). This target article formulates three core principles (with corollaries) to provide a foundation for psychological situation research: the Processing, Reality and Circularity Principles. These principles build upon each other, ranging from basic to more complex issues (e.g. how to study situations in both objective and subjective terms). They are intended to guide and spur more coherent research programs that produce cumulative knowledge on psychological situations. We conclude with a plea for real–life, multi–method, multi–situation, multi–time, multi–group designs that can illuminate the interwoven dynamics between persons (with their personalities and behaviour) and situations. Copyright © 2015 European Association of Personality Psychology

Why Not Everyone Gets Their Fair Share of Stress: Adolescent'S Perceived Relationship Affection Mediates Associations between Temperament and Subsequent Stressful Social Events

Temperamental differences are associated with subsequent stressful life events, a phenomenon that has in part been attributed to evocation. However, we remain ignorant about the mechanisms that mediate this process. In the current paper, we test whether differences in ‘perceived relationship affection’ accounted for part of the prospective association between temperament and stressful social event evocation in three social domains, viz. parents, peers and romantic partners. Data were derived from the Tracking Adolescents’ Individual Lives Survey, a large population cohort of Dutch adolescents ( n = 1158). Parent–reported adolescent temperament and adolescent's perceived affection were assessed at age 11 years. Stressful social events that occurred between age 11 and 16 years were captured using the event history calendar. Results indicate that adolescents evoke subsequent stressful social events based on their temperament, and that this association is partially mediated by perceived affection. Importantly, we found evidence for both generic and domain–specific associations, which indicates that social domains are related yet distinct. Taken together, the findings suggest that a search for mediating variables may be a promising way to increase our understanding of the mechanisms that underlie the social stress selection principle, and that perceived relationship affection is one of the candidates. Copyright © 2015 European Association of Personality Psychology

Genetic and environmental continuity in personality development: a meta-analysis

The longitudinal stability of personality is low in childhood but increases substantially into adulthood. Theoretical explanations for this trend differ in the emphasis placed on intrinsic maturation and socializing influences. To what extent does the increasing stability of personality result from the continuity and crystallization of genetically influenced individual differences, and to what extent does the increasing stability of life experiences explain increases in personality trait stability? Behavioral genetic studies, which decompose longitudinal stability into sources associated with genetic and environmental variation, can help to address this question. We aggregated effect sizes from 24 longitudinal behavioral genetic studies containing information on a total of 21,057 sibling pairs from 6 types that varied in terms of genetic relatedness and ranged in age from infancy to old age. A combination of linear and nonlinear meta-analytic regression models were used to evaluate age trends in levels of heritability and environmentality, stabilities of genetic and environmental effects, and the contributions of genetic and environmental effects to overall phenotypic stability. Both the genetic and environmental influences on personality increase in stability with age. The contribution of genetic effects to phenotypic stability is moderate in magnitude and relatively constant with age, in part because of small-to-moderate decreases in the heritability of personality over child development that offset increases in genetic stability. In contrast, the contribution of environmental effects to phenotypic stability increases from near zero in early childhood to moderate in adulthood. The life-span trend of increasing phenotypic stability, therefore, predominantly results from environmental mechanisms.

What Drives Adult Personality Development? A Comparison of Theoretical Perspectives and Empirical Evidence

Increasing numbers of empirical studies provide compelling evidence that personality traits change across the entire lifespan. What initiates this continuing personality development and how does this development proceed? In this paper, we compare six theoretical perspectives that offer testable predictions about why personality develops the way it does and identify limitations and potentials of these perspectives by reviewing how they hold up against the empirical evidence. While all of these perspectives have received some empirical support, there is only little direct evidence for propositions put forward by the five–factor theory of personality and the theory of genotype → environment effects. In contrast, the neo–socioanalytic theory appears to offer a comprehensive framework that fits the empirical findings and allows the integration of other, more specialized, perspectives that focus on specific aspects of personality development like the role of time, systematic differences between categories of social roles or the active partake of the person himself or herself. We draw conclusions on the likely driving factors for adult personality development and identify avenues for future research. Copyright © 2014 European Association of Personality Psychology

Studying Changes in Life Circumstances and Personality: It's about Time

Most theories of personality development posit that changes in life circumstances (e.g. due to major life events) can lead to changes in personality, but few studies have examined the exact time course of these changes. In this article, we argue that time needs to be considered explicitly in theories and empirical studies on personality development. We discuss six notions on the role of time in personality development. First, people can differ before the event. Second, change can be non–linear and discontinuous. Third, change can be reversible. Fourth, change can occur before the event. Fifth, control groups are needed to disentangle age–related and event–related changes. Sixth, we need to move beyond examining single major life events and study the effects of non–normative events, non–events, multiple events, and minor events on personality. We conclude by summarizing the methodological and theoretical implications of these notions. Copyright © 2014 European Association of Personality Psychology

The Behavioural Genetics of Personality Development in Adulthood—Classic, Contemporary, and Future Trends

Behavioural genetic research has led to important advances in the field of personality psychology. When carried out on longitudinal data, behavioural genetic studies also offer promising ways to examine the genetic and environmental origins of personality stability and change. Here, we review the findings of longitudinal twin studies, discuss their implications for our understanding of adult personality development, and point out open questions that need to be addressed by future research. Three general conclusions stand out. First, there is a strong and relatively stable genetic foundation of individual differences in personality throughout the adult life span; second, environmental influences become more important and contribute to an increasing rank–order stability of personality traits from early to middle adulthood; and third, both genetic and nonshared environmental influences contribute to both stability and change in personality traits. Equipped with this knowledge, the most urgent tasks for the next generation of behavioural genetic studies on personality development will be to (i) identify measurable environmental factors that matter and (ii) to capture the interplay between genetic and environmental influences on personality stability and change throughout adulthood. Copyright © 2014 European Association of Personality Psychology

Timing of Stressful Life Events Affects Stability and Change of Neuroticism

Neuroticism is a predictor of many health problems. To study the determinants of within–subject change in neuroticism, three hypotheses were tested: (i) subjects who experienced stressful life events (SLEs) show an increase in neuroticism; (ii) high baseline neuroticism moderated this effect; and (iii) recent SLEs had a greater impact on neuroticism than distant SLEs. Data came from the Finnish Twin Cohort. Neuroticism data were collected in 1975 and 1981 and SLEs data in 1981 (n = 21 085). By entering baseline neuroticism as a predictor for neuroticism at follow–up, the outcome measure was change in neuroticism. Changes in neuroticism were predicted from SLE indices or their interaction with baseline neuroticism. Timing of SLEs was taken into account by distinguishing recent from distant SLEs. To control for confounding by shared genes and environments, both within–twin pair and between–twin pair effects were tested for monozygotic and dizygotic twin pairs separately. Neuroticism's six–year stability was high (r = .58, p < .001). Exposure to SLEs modestly increased neuroticism (βs > .55, ps < .001), unconfounded by shared genes. This effect was not moderated by high baseline neuroticism. Recent SLEs (.09 < βs < .15) had more impact than distant SLEs (.03 < βs < .11; ps < .01). In conclusion, the findings strongly supported a model of environmentally driven SLEs causing dynamic fluctuations around a person's set point of neuroticism. Copyright © 2013 John Wiley & Sons, Ltd.

The course of personality pathology

PURPOSE OF REVIEW

Durability has traditionally been considered to be a defining feature of personality disorders, but recent studies have challenged this notion. We review the most recent findings on the stability and course of personality pathology.

RECENT FINDINGS

Personality disorders seem to remit more often and faster than previously thought, and their relapse rate is low. However, the recent optimism regarding these disorders is mitigated by the existence of highly heterogeneous trajectories among patients and traits, the identification of certain methodological shortcomings, and the maintenance of psychosocial impairment long after symptomatic relief. The causes of personality improvement are largely unknown, but involve intermingled genetic and environmental effects.

SUMMARY

Recent follow-up studies of patients with personality pathology are changing orthodox conceptions of their inevitably negative prognosis. The current taxonomies must be reviewed and future research should be integrated with adjacent fields. Treatments need to target the enduring real-life hardships of these patients, apart from their acute symptoms.

Estimating the heritability of reporting stressful life events captured by common genetic variants

BACKGROUND

Although usually thought of as external environmental stressors, a significant heritable component has been reported for measures of stressful life events (SLEs) in twin studies. Method We examined the variance in SLEs captured by common genetic variants from a genome-wide association study (GWAS) of 2578 individuals. Genome-wide complex trait analysis (GCTA) was used to estimate the phenotypic variance tagged by single nucleotide polymorphisms (SNPs). We also performed a GWAS on the number of SLEs, and looked at correlations between siblings.

RESULTS

A significant proportion of variance in SLEs was captured by SNPs (30%, p = 0.04). When events were divided into those considered to be dependent or independent, an equal amount of variance was explained for both. This 'heritability' was in part confounded by personality measures of neuroticism and psychoticism. A GWAS for the total number of SLEs revealed one SNP that reached genome-wide significance (p = 4 × 10-8), although this association was not replicated in separate samples. Using available sibling data for 744 individuals, we also found a significant positive correlation of R 2 = 0.08 in SLEs (p = 0.03).

CONCLUSIONS

These results provide independent validation from molecular data for the heritability of reporting environmental measures, and show that this heritability is in part due to both common variants and the confounding effect of personality.

The Bielefeld Longitudinal Study of Adult Twins (BiLSAT)

The Bielefeld Longitudinal Study of Adult Twins (BiLSAT) is a German longitudinal study of monozygotic and dizygotic twins reared together, including more than 1,100 twin pairs aged between 14 and 80 who participated in the first wave. Data were collected at five waves of assessment between 1993 and 2009. Initially, the study focused on genetic and environmental influences on the structure and the development in adult temperament and personality. Today, the study includes a broad range of individual variables, such as personality disorders, major life goals, interests, attitudes, values, life and work satisfaction, and major life events. A special feature of this genetically informative study lies in the multiple-rater approach (i.e., self-reports and peer reports). Longitudinal multiple-rater analyses allow researchers to go beyond the basic nature-nurture decomposition of variance in self-reports examining genetic and environmental influences on stability and change in more accurately measured individual attributes. In the current article, we briefly describe the design and contents of BiLSAT as well as some recent major findings and future plans.