Is neuroticism really bad for you? Dynamics in personality and limbic reactivity prior to, during and following real-life combat stress

Stress-induced increase in heart-rate during sleep as an indicator of PTSD risk among combat soldiers

STUDY OBJECTIVES

Discerning the differential contribution of sleep behavior and sleep physiology to the subsequent development of posttraumatic-stress-disorder (PTSD) symptoms following military operational service among combat soldiers.

METHODS

Longitudinal design with three measurement time points: during basic training week (T1), during intensive stressed training week (T2), and following military operational service (T3). Participating soldiers were all from the same unit, ensuring equivalent training schedules and stress exposures. During measurement weeks soldiers completed the Depression Anxiety and Stress Scale (DASS) and the PTSD Checklist for DSM-5 (PCL-5). Sleep physiology (sleep heart-rate) and sleep behavior (duration, efficiency) were monitored continuously in natural settings during T1 and T2 weeks using wearable sensors.

RESULTS

Repeated measures ANOVA revealed a progressive increase in PCL-5 scores from T1 and T2 to T3, suggesting an escalation in PTSD symptom severity following operational service. Hierarchical linear regression analysis uncovered a significant relation between the change in DASS stress scores from T1 to T2 and subsequent PCL-5 scores at T3. Incorporating participants' sleep heart-rate markedly enhanced the predictive accuracy of the model, with increased sleep heart-rate from T1 to T2 emerging as a significant predictor of elevated PTSD symptoms at T3, above and beyond the contribution of DASS stress scores. Sleep behavior did not add to the accuracy of the model.

CONCLUSION

Findings underscore the critical role of sleep physiology, specifically elevated sleep heart-rate following stressful military training, in indicating subsequent PTSD risk following operational service among combat soldiers. These findings may contribute to PTSD prediction and prevention efforts.

A genome-wide investigation into the underlying genetic architecture of personality traits and overlap with psychopathology

Personality is influenced by both genetic and environmental factors and is associated with other psychiatric traits such as anxiety and depression. The 'big five' personality traits, which include neuroticism, extraversion, agreeableness, conscientiousness and openness, are a widely accepted and influential framework for understanding and describing human personality. Of the big five personality traits, neuroticism has most often been the focus of genetic studies and is linked to various mental illnesses, including depression, anxiety and schizophrenia. Our knowledge of the genetic architecture of the other four personality traits is more limited. Here, utilizing the Million Veteran Program cohort, we conducted a genome-wide association study in individuals of European and African ancestry. Adding other published data, we performed genome-wide association study meta-analysis for each of the five personality traits with sample sizes ranging from 237,390 to 682,688. We identified 208, 14, 3, 2 and 7 independent genome-wide significant loci associated with neuroticism, extraversion, agreeableness, conscientiousness and openness, respectively. These findings represent 62 novel loci for neuroticism, as well as the first genome-wide significant loci discovered for agreeableness. Gene-based association testing revealed 254 genes showing significant association with at least one of the five personality traits. Transcriptome-wide and proteome-wide analysis identified altered expression of genes and proteins such as CRHR1, SLC12A5, MAPT and STX4. Pathway enrichment and drug perturbation analyses identified complex biology underlying human personality traits. We also studied the inter-relationship of personality traits with 1,437 other traits in a phenome-wide genetic correlation analysis, identifying new associations. Mendelian randomization showed positive bidirectional effects between neuroticism and depression and anxiety, while a negative bidirectional effect was observed for agreeableness and these psychiatric traits. This study improves our comprehensive understanding of the genetic architecture underlying personality traits and their relationship to other complex human traits.

The role of familial factors and neuroticism in the association between exposure to offensive behaviors at work and long-term sickness absence due to common mental disorders - a prospective twin study

OBJECTIVES

The aim of this study was to investigate associations between exposure to work-related violence/threats and harassment, and future sickness absence (SA) due to common mental disorders (CMDs), taking familial factors (shared genetics and early-life environment) and neuroticism into account.

METHODS

The study sample included 8795 twin individuals from the Swedish Twin Project of Disability Pension and Sickness Absence (STODS), including survey data from the Study of Twin Adults: Genes and Environment (STAGE). Self-reported work-related violence and/or threats as well as work-related harassment (including bullying) and national register data on SA due to CMDs were analyzed using standard logistic regression, and conditional logistic regression among complete twin pairs discordant on exposures. Individuals were followed for a maximum of 13 years. Interactions between neuroticism and exposures were assessed using both multiplicative and additive interaction analyses.

RESULTS

Exposure to work-related violence/threats was associated with higher odds of SA due to CMDs when adjusting for age, sex, marital status, children, education, type of living area, work characteristics, and symptoms of depression and burnout (OR 2.11, 95% CI 1.52-2.95). Higher odds of SA due to CMDs were also found for exposure to harassment (OR 1.52, 95% CI 1.10-2.11) and a combined indicator of exposure to violence/threats and/or harassment (OR 1.98, 95% CI 1.52-2.59), compared with the unexposed. Analyses of twins discordant on exposure, using the unexposed co-twin as reference, showed reduced ORs. These ORs were still elevated but no longer statistically significant, potentially due to a lack of statistical power. No multiplicative interaction was found between neuroticism and exposure to work-related violence/threats, or harassment. However, a statistically significant additive interaction was found between neuroticism and exposure to violence/threats, indicating higher odds of SA due to CMDs in the group scoring lower on neuroticism.

CONCLUSIONS

Exposure to work-related offensive behaviors was associated with SA due to CMDs. However, the results indicated that these associations may be partly confounded by familial factors. In addition, an interaction between exposure and neuroticism was suggested. Thus, when possible, future studies investigating associations and causality between offensive behaviors at work and mental health-related outcomes, should consider familial factors and neuroticism.

A genome-wide investigation into the underlying genetic architecture of personality traits and overlap with psychopathology

Personality is influenced by both genetic and environmental factors and is associated with other psychiatric traits such as anxiety and depression. The "Big Five" personality traits, which include neuroticism, extraversion, agreeableness, conscientiousness, and openness, are a widely accepted and influential framework for understanding and describing human personality. Of the big five personality traits, neuroticism has most often been the focus of genetic studies and is linked to various mental illnesses including depression, anxiety, and schizophrenia. Our knowledge of the genetic architecture of the other four personality traits is more limited. Utilizing the Million Veteran Program (MVP) cohort we conducted a genome-wide association study (GWAS) in individuals of European and African ancestry. Adding other published data, we performed GWAS meta-analysis for each of the five personality traits with sample sizes ranging from 237,390 to 682,688. We identified 158, 14, 3, 2, and 7 independent genome-wide significant (GWS) loci associated with neuroticism, extraversion, agreeableness, conscientiousness, and openness, respectively. These findings represent 55 novel loci for neuroticism, as well as the first GWS loci discovered for extraversion and agreeableness. Gene-based association testing revealed 254 genes showing significant association with at least one of the five personality traits. Transcriptome-wide and proteome-wide analysis identified altered expression of genes and proteins such as CRHR1, SLC12A5, MAPT, and STX4. Pathway enrichment and drug perturbation analyses identified complex biology underlying human personality traits. We also studied the inter-relationship of personality traits with 1,437 other traits in a phenome-wide genetic correlation analysis, identifying new associations. Mendelian randomization showed positive bidirectional effects between neuroticism and depression and anxiety while a negative bidirectional effect was observed for agreeableness and these psychiatric traits. This study improves our comprehensive understanding of the genetic architecture underlying personality traits and their relationship to other complex human traits.

Neurobiological correlates of resilience during childhood and adolescence - A systematic review

Research examining the neurobiological mechanisms of resilience has grown rapidly over the past decade. However, there is vast heterogeneity in research study design, methods, and in how resilience is operationalized, making it difficult to gauge what we currently know about resilience biomarkers. This preregistered systematic review aimed to review and synthesize the extant literature to identify neurobiological correlates of resilience to adversity during childhood and adolescence. Literature searches on MEDLINE and PsycINFO yielded 3834 studies and a total of 49 studies were included in the final review. Findings were synthesized based on how resilience was conceptualized (e.g., absence of psychopathology, trait resilience), and where relevant, the type of outcome examined (e.g., internalizing symptoms, post-traumatic stress disorder). Our synthesis showed that findings were generally mixed. Nevertheless, some consistent findings suggest that resilience neural mechanisms may involve prefrontal and subcortical regions structure/activity, as well as connectivity between these regions. Given substantial heterogeneity in the definition and operationalization of resilience, more methodological consistency across studies is required for advancing knowledge in this field.

The impact of childhood trauma on perceived stress and personality in patients with obsessive-compulsive disorder: A cross-sectional network analysis

OBJECTIVE

Little is known about the role of childhood experiences in the development of obsessive-compulsive disorder (OCD). However, the influence of childhood experiences on personality, behavior, and perceived stress may vary between OCD patients and healthy individuals. The objective of this study was to use network analysis to explore the relationship between childhood trauma, personality, perceived stress, and symptom dimensions, thus finding the difference between patients' and healthy people's network.

METHODS

488 patients with OCD and 210 healthy volunteers were recruited. All of them were assessed with the Obsessive-Compulsive Inventory - Revised (OCI-R), the Perceived Stress Scale-10, the NEO Five-Factor Inventory and the Early Trauma Inventory Self-Report Short Form. Network analysis was conducted and the centrality indices were calculated. Network comparison test was performed.

RESULTS

In patients' network, the Obsession and the Ordering behavior were the most important nodes among the OCI-R. The perceived stress showed the strongest strength centrality of all nodes and positive correlation with the Obsession and Neuroticism. Network comparison test results indicated a statistically significant difference between network structure, and post-hoc analysis found five edges significantly differed between patients and healthy controls, mainly on Obsession and Washing behaviors.

CONCLUSIONS

Emotional abuse was considered significant in both networks due to its higher strength centrality. Meanwhile, perceived stress was found to be more significant in the patient network and exhibited stronger associations with obsession. The obsessive thoughts and washing behavior were different among patients and healthy controls, which brought new understanding to the pathopsychological mechanisms of OCD.

The influence of family incivility on cyberbullying perpetration: A moderated mediation model

Previous research has extended the stress literature by exploring the relationship between family incivility and cyberbullying perpetration, yet relatively less attention has been paid to underlying psychological mechanisms between that relationship among university students. According to the Frustration-Aggression Theory, this study examined the relationships of family incivility, cyberbullying perpetration, negative emotions and neuroticism among Chinese university students. Data were collected from 814 university students (females, N = 423; Mage = 19.96 years, SD = 3.09). The results examined the mechanism through which family incivility was significantly related to cyberbullying perpetration through the mediation of negative emotions, suggesting a strong link of stressful life events to online aggression. In addition, high levels of neuroticism moderated the relationship between family incivility and cyberbullying perpetration, as well as that between family incivility and negative emotions. The study revealed the chronic and potential impact of family incivility, underlined the interaction between stressful life events and online aggression, and put forward the intervention strategies of cyberbullying among university students.

The mediating effect of symptoms of posttraumatic stress disorder and depression on the relationship between personality traits and quality of life in emergency service workers

BACKGROUND

Emergency service workers are often exposed to fatalities during accidents or disasters. Therefore, they may be more prone to experiencing posttraumatic stress disorder (PTSD) and depression. It has been shown that these comorbid disorders are related to personality traits and quality of life (QOL).

METHODS

We hypothesized that mental disorders, such as symptoms of PTSD and depression, mediate the relationship between personality traits, as measured on the 10-Item Personality Inventory (TIPI), and QOL, as measured on the MOS 36-item Short-Form Health Survey (SF-36).

RESULTS

Participants were aged 23-61 years. Questionnaires were sent to 373 participants, 220 of whom returned responses. A direct effect was found between two subscales of the TIPI (Extraversion and Emotional stability) and mental component summary scores of the SF-36 (Extraversion: β = 0.154, p < .001; Emotional stability: β = 0.179, p < .001), which indicated partial mediation. A significant indirect effect was revealed between two personality traits and mental health summary scores (Extraversion: β = 0.058, p < .001; Emotional stability: β = 0.087, p < .001). We also found a direct effect of extraversion scores of the TIPI on role/social component summary scores of the SF-36 (β = 0.084, p < .05). However, none of the 95% confidential intervals was significant, which indicated full mediation, and the indirect effect was significant (β = 0.023, p < .01). Sensitivity analysis indicated that a direct effect between extraversion scores of the TIPI and role/social component summary scores of the SF-36 was significant, which indicated partial mediation.

CONCLUSIONS

The findings of direct and indirect effects highlight the importance of identifying effective methods for protecting individuals from developing symptoms of PTSD and depression; moreover, they may help improve QOL. The capacity of dealing with incidents among emergency service workers may vary depending on their personality traits. Therefore, the screening of mental health states that includes a personality trait inventory may be valuable.