Heritability estimates of the Big Five personality traits based on common genetic variants

According to twin studies, the Big Five personality traits have substantial heritable components explaining 40–60% of the variance, but identification of associated genetic variants has remained elusive. Consequently, knowledge regarding the molecular genetic architecture of personality and to what extent it is shared across the different personality traits is limited. Using genomic-relatedness-matrix residual maximum likelihood analysis (GREML), we here estimated the heritability of the Big Five personality factors (extraversion, agreeableness, conscientiousness, neuroticism and openness for experience) in a sample of 5011 European adults from 527 469 single-nucleotide polymorphisms across the genome. We tested for the heritability of each personality trait, as well as for the genetic overlap between the personality factors. We found significant and substantial heritability estimates for neuroticism (15%, s.e.=0.08, P=0.04) and openness (21%, s.e.=0.08, P<0.01), but not for extraversion, agreeableness and conscientiousness. The bivariate analyses showed that the variance explained by common variants entirely overlapped between neuroticism and openness (rG=1.00, P <0.001), despite low phenotypic correlation (r=−0.09, P <0.001), suggesting that the remaining unique heritability may be determined by rare or structural variants. As far as we are aware of, this is the first study estimating the shared and unique heritability of all Big Five personality traits using the GREML approach. Findings should be considered exploratory and suggest that detectable heritability estimates based on common variants is shared between neuroticism and openness to experiences.     

Common SNPs explain some of the variation in the personality dimensions of neuroticism and extraversion

The personality traits of neuroticism and extraversion are predictive of a number of social and behavioural outcomes and psychiatric disorders. Twin and family studies have reported moderate heritability estimates for both traits. Few associations have been reported between genetic variants and neuroticism/extraversion, but hardly any have been replicated. Moreover, the ones that have been replicated explain only a small proportion of the heritability (<∼2%). Using genome-wide single-nucleotide polymorphism (SNP) data from ∼12 000 unrelated individuals we estimated the proportion of phenotypic variance explained by variants in linkage disequilibrium with common SNPs as 0.06 (s.e.=0.03) for neuroticism and 0.12 (s.e.=0.03) for extraversion. In an additional series of analyses in a family-based sample, we show that while for both traits ∼45% of the phenotypic variance can be explained by pedigree data (that is, expected genetic similarity) one third of this can be explained by SNP data (that is, realized genetic similarity). A part of the so-called ‘missing heritability'' has now been accounted for, but some of the reported heritability is still unexplained. Possible explanations for the remaining missing heritability are that: (i) rare variants that are not captured by common SNPs on current genotype platforms make a major contribution; and/ or (ii) the estimates of narrow sense heritability from twin and family studies are biased upwards, for example, by not properly accounting for nonadditive genetic factors and/or (common) environmental factors.     

Anxiety and depressive disorders and the five-factor model of personality: a higher- and lower-order personality trait investigation in a community sample

We describe in detail normal personality traits in persons with psychiatrist-ascertained anxiety and depressive disorders in a general population sample. We investigated Revised NEO Personality Inventory traits in 731 community subjects examined by psychiatrists with the Schedules for Clinical Assessment in Neuropsychiatry. All of the lifetime disorders of interest (simple phobia, social phobia, agoraphobia, panic disorder, obsessive-compulsive disorder (OCD), generalized anxiety disorder, major depressive disorder (MDD), and dysthymia) were associated with high neuroticism. Social phobia, agoraphobia, and dysthymia were associated with low extraversion, and OCD was associated with high openness to experience. In addition, lower-order facets of extraversion (E), openness (O), agreeableness (A), and conscientiousness (C) were associated with certain disorders (specifically, low assertiveness (E) and high openness to feelings (O) with MDD, low trust (A) with social phobia and agoraphobia, low self-discipline (C) with several of the disorders, and low competence and achievement striving (C) with social phobia). Neuroticism in particular was related to acuity of disorder. Longitudinal study is necessary to differentiate state versus pathoplastic effects.     

Adult attention-deficit/hyperactivity disorder in major depressed and bipolar subjects: role of personality traits and clinical implications

A significant comorbidity between attention-deficit/hyperactivity disorder (ADHD) and affective disorders has been consistently reported in adults. Less data regarding the role of personality traits and the influence of ADHD co-occurrence on clinical characteristics and outcome of mood disorders are currently available. One hundred and six remitted major depressed, 102 euthymic bipolar subjects, and 120 healthy controls, homogeneous with respect to demographic characteristics, were included in the study. ADHD diagnosis was based on DSM-IV-TR criteria. Childhood and adult ADHD features were measured with the Wender Utah Rating Scale, the Adult ADHD Self-rating Scale, and the Brown Attention-Deficit Disorder Scale. The Revised NEO Personality Inventory was also administered to the clinical groups, in order to investigate personality dimensions. The occurrence of adult ADHD in subjects with bipolar disorders (BD) or major depressive disorder (MDD) was 15.7 and 7.5 %, respectively, compared to 3.3 % in healthy controls (HC). Significant associations (p < .001) between personality traits (neuroticism, conscientiousness, and extraversion) and ADHD features were observed. Logistic regression analysis of all clinical subjects (n = 208) showed that those with lower levels of neuroticism (OR = 1.031; p = .025) had a lower frequency of ADHD comorbidity. The present study emphasizes the close relationship between affective disorders, especially BD, and ADHD in adults. Our findings support the need to assess subjects with mood disorders in the clinical setting for possible coexisting ADHD and to further investigate personality traits to better understand the etiology of affective disorders and ADHD co-occurrence.     

The state effect of depressive and anxiety disorders on big five personality traits

BackgroundNeuroticism and extraversion are affected by depressive disorder state. Less is known about depressive state effects on conscientiousness, agreeableness and openness. Furthermore, state effects of anxiety disorders on personality have been far less studied than those of depressive disorder. Here, we aim to determine the extent of change in all five personality traits associated with the occurrence of or recovery from depressive and anxiety disorders.MethodsUsing the Composite International Diagnostic Interview (CIDI) at baseline and two-year follow-up, respondents from the Netherlands Study of Depression and Anxiety (NESDA) were divided into four groups: unaffected at baseline and follow-up, occurrence, recovery, and affected at baseline and follow-up. Personality change (NEO-five factor inventory) was examined in the occurrence and recovery groups relative to the unaffected and affected groups, respectively. Analyses were repeated, differentiating between (specific) depressive and anxiety disorders.ResultsWe found small state effects of affective disorders on neuroticism, extraversion and conscientiousness. Corrected for each other, both depressive and anxiety disorders showed small state effects on neuroticism, but effects on extraversion and conscientiousness were mainly associated with depressive disorders.ConclusionsState effects were small. When assessing neuroticism, the presence of both depressive and anxiety disorders should be taken into account, as both may independently increase neuroticism scores. However, when assessing extraversion and conscientiousness, depressive disorders but not anxiety disorders are likely to be of influence. Agreeableness and openness are influenced by neither.     

Do clinical evaluations in a psychiatry clerkship favor students with positive personality characteristics?

OBJECTIVE: The authors examine associations of personality characteristics, National Board of Medical Examiners subject examination performance, and Objective Structured Clinical Examination performance with clinical evaluations of third-year medical students in a psychiatry clerkship. METHODS: Students completed the Revised NEO Personality Inventory, which measures personality domains of neuroticism, extraversion, openness, agreeableness, and conscientiousness and associated personality traits. At clerkship completion, students completed the National Board of Medical Examiners subject examination and a psychiatry Objective Structured Clinical Examination, and were evaluated by attending physicians (using a standardized evaluation form) regarding their clinical "knowledge and skill" and "interpersonal behavior." Data were analyzed using Pearson correlation and canonical correlation. RESULTS: National Board of Medical Examiners subject examination and Objective Structured Clinical Examination scores were uncorrelated with clinical evaluations of "knowledge and skill" and "interpersonal behavior." Personality variables explained a moderate amount of variance in clinical evaluations. "Knowledge and skill" was positively associated with the domain of conscientiousness, the extraversion trait of warmth, and the conscientiousness traits of competence and achievement striving. "Interpersonal behavior" was negatively associated with the neuroticism trait of angry hostility and positively associated with the domain of agreeableness; the extraversion traits of warmth, gregariousness, and positive emotions; and the agreeableness traits of trust, altruism, compliance, and tender-mindedness. CONCLUSION: Clinical evaluations of medical students may favor personality styles that reflect positive elements of extraversion, agreeableness, and conscientiousness. The present findings raise questions regarding the validity of clinical evaluation elements in clerkship performance appraisal.     

The influence of polygenic risk for bipolar disorder on neural activation assessed using fMRI

Genome-wide association studies (GWAS) have demonstrated a significant polygenic contribution to bipolar disorder (BD) where disease risk is determined by the summation of many alleles of small individual magnitude. Modelling polygenic risk scores may be a powerful way of identifying disrupted brain regions whose genetic architecture is related to that of BD. We determined the extent to which common genetic variation underlying risk to BD affected neural activation during an executive processing/language task in individuals at familial risk of BD and healthy controls. Polygenic risk scores were calculated for each individual based on GWAS data from the Psychiatric GWAS Consortium Bipolar Disorder Working Group (PGC-BD) of over 16 000 subjects. The familial group had a significantly higher polygene score than the control group (P=0.04). There were no significant group by polygene interaction effects in terms of association with brain activation. However, we did find that an increasing polygenic risk allele load for BD was associated with increased activation in limbic regions previously implicated in BD, including the anterior cingulate cortex and amygdala, across both groups. The findings suggest that this novel polygenic approach to examine brain-imaging data may be a useful means of identifying genetically mediated traits mechanistically linked to the aetiology of BD.     

A dimensional approach to assessing personality functioning: examining personality trait domains utilizing DSM-IV personality disorder criteria

BackgroundThis study compared a dimensional, trait domain approach to characterizing personality pathology with the traditional polythetic approach with respect to their associations with interpersonal functioning and personality traits from the five factor model.MethodsPsychiatric inpatients (N = 1476) were administered the Structured Clinical Interview for DSM-IV Axis II personality disorders. Dimensional representations of trait domains were derived from reorganizing DSM-IV criteria into personality trait domains from DSM-5 Alternative Model. Dimensional scores and personality disorder (PD) total criterion scores served as independent variables in predicting interpersonal profile clusters, as well as extraversion, agreeableness conscientiousness, neuroticism and openness from the five factor model traits.ResultsTrait domain scores and PD criteria totals were significantly correlated with submissive interpersonal style yet none proved significant in regression analyses. Avoidant and borderline PD total criteria were negatively associated with a normative interpersonal style. Combined trait domain of detachment and avoidant PD total criteria predicted a hostile/withdrawn interpersonal style. The trait domain of detachment was negatively associated with five factor traits of extroversion, whereas borderline PD total criteria were negatively associated with conscientiousness. Avoidant and borderline PD total criteria were positively associated with neuroticism.ConclusionsThe cross-cutting dimensional approach provided useful information in predicting a hostile/withdrawn interpersonal style as well as extroversion. Importantly, PD criterion scores and dimensional trait scores combined to predict this interpersonal style providing support to the alternative model of personality diagnosis in DSM-5. Clinicians are encouraged to assess dimensions of personality traits as these are related to interpersonal problems frequently encountered in psychiatric settings. While potentially useful, the dimensional approach articulated here did not yield substantial prediction of behavior.     

Personality disorders and traits in patients with body dysmorphic disorder

Individuals with body dysmorphic disorder (BDD) have been postulated to have schizoid, narcissistic, and obsessional personality traits and to be sensitive, introverted, perfectionistic, and insecure. However, data on personality traits and disorders in BDD are limited. This study assessed 148 subjects with BDD, 26 of whom participated in a fluvoxamine treatment study; 74 subjects were assessed for personality disorders with the Structured Clinical Interview for DSMIII-R Personality Disorders (SCID-II), 100 subjects completed the NEO-Five Factor Inventory (NEO-FFI), and 51 subjects completed the Rathus Assertiveness Scale. Forty-two subjects (57%) had one or more personality disorders, with avoidant personality disorder (43%) being most common, followed by dependent (15%), obsessive-compulsive (14%), and paranoid (14%) personality disorders. On the NEO-FFI, the mean scores were in the very high range for neuroticism, the low range for extraversion and conscientiousness, the low-average range for agreeableness, and the average range for openness to experience. On the Rathus Assertiveness Scale, the mean score was -17.1 +/- 32.0 for women and -17.0 +/- 32.3 for men. Among fluvoxamine responders, the number of personality disorders significantly decreased between the study baseline and endpoint. These findings suggest that the rate of personality disorders in BDD is relatively high, with avoidant personality disorder being most common. The high neuroticism scores and low extraversion scores are consistent with this finding.     

The association between personality traits and treatment outcomes in Korean patients with lower urinary tract symptoms suggestive of benign prostatic hyperplasia (LUTS/BPH): a preliminary study

Objective

We investigated the association between personality traits and treatment outcomes in male Korean patients with lower urinary tract symptoms suggestive of benign prostatic hyperplasia (LUTS/BPH).

Method

We evaluated the personality traits and the severity of LUTS/BPH symptoms at baseline using the Korean versions of the 44-item Big Five Inventory (BFI-K) and International Prostate Symptom Score (IPSS), respectively. The IPSS was re-administered following a 12-week routine treatment regime, and we examined the relationship between treatment outcome and personality traits.

Results

Of the 176 patients initially screened, 101 agreed to participate in the study. Of those, 93 (92.1%) completed the 12-week trial and the BFI-K. Neuroticism was associated with a significantly worse treatment response, whereas extraversion was associated with a significantly better treatment response, and openness was associated with a high responder rate. Agreeableness, openness and conscientiousness were associated with improved week-12 IPSS total scores; however, the results were not statistically significant.

Conclusions

We found an association between treatment response and personality traits of neuroticism, extraversion and openness in patients with LUTS/BPH. However, further studies with larger samples and an improved design are needed to support our findings.     

The impact of personality on symptom expression in obsessive-compulsive disorder

Previous research conducted on the five-factor model of personality (FFM) in obsessive-compulsive disorder (OCD) has demonstrated that community and clinical participants score significantly higher than controls on the domains and facets of neuroticism and extraversion and selective facets of agreeableness and conscientiousness. However, studies have yet to examine the extent to which personality traits, as assessed by the FFM, are associated with the specific symptoms of OCD. The purpose of this study was to examine further the personality predictors of obsessive-compulsive symptoms in clinical participants using the facets of the FFM. Patients with a DSM-IV diagnosis of OCD (N = 56) completed the Revised NEO Personality Inventory, the Yale Brown Obsession Compulsion Scale, and the Beck Depression Inventory. Lower scores on openness to ideas were uniquely associated with greater obsession severity, whereas lower openness to actions was uniquely associated with greater compulsive severity. In contrast with past research that has emphasized the association between neuroticism and extraversion and dimensionally rated obsessive-compulsive symptoms, this study demonstrates the specific associations between selective facet traits of openness and clinical obsessions and compulsions. Whereas tendencies toward negative affectivity may confer a nonspecific vulnerability to the development of OCD, facets of openness may impact on the particular expression and severity of obsessive-compulsive symptoms.     

Neuroticism may be associated with history of depression in the elderly

The relationships between geriatric depression and various personality traits have never been fully clarified, and their clinical significance is uncertain. Depression in geriatric patients may differ from the disorder found in younger individuals, and may also have distinctive personality antecedents or consequences. In this study 16 elderly subjects who had recovered from depression and 14 elderly control completed the Eysenck Personality Inventory (EPI) and the Personality Disorder Examination (PDE). On the EPI, neuroticism subscale scores were significantly higher for patients than controls, while mean extraversion scores were not significantly different. On the PDE, recovered depressives had higher dimensional scores than controls in each DSM-III-R personality disorder except antisocial. Neuroticism scores correlated significantly with PDE dimensional scores for all but two of the DSM-III-R personality disorders, while extraversion scores correlated significantly with only two PDE categories. Together, these findings suggest that neuroticism and criteria for most DSM-III-R personality disorders may be associated with history of depression in a geriatric population.     

首发未用药抑郁症患者大五人格特征对照研究

目的探讨首发未服药抑郁症患者的大五人格特征。方法采用大五人格量表简化版(neuroticism extraversion openness five-factor inventory,NEO-FFI),对112例首发未服药抑郁症患者及99名性别、年龄、文化背景相匹配的正常对照进行大五人格特征评估,汉密尔顿抑郁量表(Hamilton depression scale,HAMD)评定患者的抑郁症状。结果患者组神经质维度得分高于对照组,而外向性、开放性、宜人性及责任感维度得分均低于对照组(P0.05)。Logistic回归分析示,抑郁症与高水平神经质(OR=1.106,95%CI:1.029~1.189)、低水平外向性(OR=0.809,95%CI:0.733~0.893)和宜人性(OR=0.870,95%CI:0.794~0.953)相关联(均P0.01)。线性回归分析示,HAMD评分仅与高水平神经质相关(B=0.121,P=0.003),发病年龄则与责任感维度得分相关(B=0.015,P=0.001)。结论本研究确认了抑郁症患者人格维度与正常对照有差异,高水平神经质维度是首发抑郁症患者的重要人格因素特征,低水平责任感则可能与抑郁症发病年龄早有关。     

Genome-wide association scan for five major dimensions of personality

Personality traits are summarized by five broad dimensions with pervasive influences on major life outcomes, strong links to psychiatric disorders and clear heritable components. To identify genetic variants associated with each of the five dimensions of personality we performed a genome-wide association (GWA) scan of 3972 individuals from a genetically isolated population within Sardinia, Italy. On the basis of the analyses of 362 129 single-nucleotide polymorphisms we found several strong signals within or near genes previously implicated in psychiatric disorders. They include the association of neuroticism with SNAP25 (rs362584, P=5 x 10(-5)), extraversion with BDNF and two cadherin genes (CDH13 and CDH23; Ps<5 x 10(-5)), openness with CNTNAP2 (rs10251794, P=3 x 10(-5)), agreeableness with CLOCK (rs6832769, P=9 x 10(-6)) and conscientiousness with DYRK1A (rs2835731, P=3 x 10(-5)). Effect sizes were small (less than 1% of variance), and most failed to replicate in the follow-up independent samples (N up to 3903), though the association between agreeableness and CLOCK was supported in two of three replication samples (overall P=2 x 10(-5)). We infer that a large number of loci may influence personality traits and disorders, requiring larger sample sizes for the GWA approach to confidently identify associated genetic variants.     

A genome-wide linkage study of individuals with high scores on NEO personality traits

The NEO-Five-Factor Inventory divides human personality traits into five dimensions: neuroticism, extraversion, openness, conscientiousness and agreeableness. In this study, we sought to identify regions harboring genes with large effects on the five NEO personality traits by performing genome-wide linkage analysis of individuals scoring in the extremes of these traits (>90th percentile). Affected-only linkage analysis was performed using an Illumina 6K linkage array in a family-based study, the Erasmus Rucphen Family study. We subsequently determined whether distinct, segregating haplotypes found with linkage analysis were associated with the trait of interest in the population. Finally, a dense single-nucleotide polymorphism genotyping array (Illumina 318K) was used to search for copy number variations (CNVs) in the associated regions. In the families with extreme phenotype scores, we found significant evidence of linkage for conscientiousness to 20p13 (rs1434789, log of odds (LOD)=5.86) and suggestive evidence of linkage (LOD >2.8) for neuroticism to 19q, 21q and 22q, extraversion to 1p, 1q, 9p and12q, openness to 12q and 19q, and agreeableness to 2p, 6q, 17q and 21q. Further analysis determined haplotypes in 21q22 for neuroticism (P-values = 0.009, 0.007), in 17q24 for agreeableness (marginal P-value = 0.018) and in 20p13 for conscientiousness (marginal P-values = 0.058, 0.038) segregating in families with large contributions to the LOD scores. No evidence for CNVs in any of the associated regions was found. Our findings imply that there may be genes with relatively large effects involved in personality traits, which may be identified with next-generation sequencing techniques.     

Associations between major psychiatric disorder polygenic risk scores and blood-based markers in UK biobank

Major depressive disorder (MDD), schizophrenia (SCZ), and bipolar disorder (BD) have both shared and discrete genetic risk factors, and are associated with peripheral abnormalities. The relationships between such genetic architectures and blood-based markers are, however, unclear.We investigated relationships between polygenic risk scores (PRS) for these disorders and peripheral markers in the UK Biobank cohort. We calculated polygenic risk scores for n = 367,329 (MDD PRS), n = 366,465 (SCZ PRS), and n = 366,383 (BD PRS) UK Biobank cohort subjects. We then examined associations between disorder PRS and 58 inflammatory/immune, hematological, bone, cardiovascular, hormone, liver, renal and diabetes-associated blood markers using two generalized linear regression models: ‘minimally adjusted’ controlling for variables such as age and sex, and ‘fully adjusted’ including additional lifestyle covariates: BMI, alcohol and smoking status, and medication intake.There were 38/58 MDD PRS, 32/58 SCZ PRS, and 20/58 BD PRS-blood marker associations detected for our minimally adjusted model. Of these, 13/38 (MDD PRS), 14/32 (SCZ PRS), and 10/20 (BD PRS) associations remained significant after controlling for lifestyle factors. Many were disorder-specific, with 8/13 unique MDD PRS associations identified. Several disorder-specific associations for MDD and SCZ were immune-related, with mostly positive and negative associations identified for MDD and SCZ PRS respectively.This study suggests that MDD, SCZ and BD have both shared and distinct peripheral markers associated with disorder-specific genetic risk. The results also implicate inflammatory dysfunction in MDD and SCZ, albeit with differences in patterns between the two conditions, and enrich our understanding of potential underlying pathophysiological mechanisms in major psychiatric disorders.     

Personality traits in schizophrenia and related personality disorders

We investigated whether schizophrenia spectrum disorders share common personality characteristics or traits. Participants with a diagnosis of schizophrenia or schizoaffective disorder (SZ) or with a schizophrenia spectrum personality disorder (schizophrenia spectrum PD: schizoid, paranoid, and schizotypal personality disorder) were compared with non-psychiatric control subjects on the five-factor model of personality and the psychosis-proneness scales. On the five-factor personality scales, SZ subjects showed higher levels of neuroticism, and lower levels of openness, agreeableness, extraversion, and conscientiousness than control subjects. Higher scores on openness and lower scores on neuroticism distinguished schizophrenia spectrum PD from SZ. On the psychosis-proneness scales, both PD and SZ participants scored high relative to non-psychiatric control participants on magical ideation and perceptual aberration, while PD participants scored intermediate between non-psychiatric control participants and SZ on social anhedonia. Discriminant analysis indicated that schizophrenia spectrum patients could be distinguished from PDs by more severe social withdrawal and maladjustment, while subjects with PDs could be best distinguished from control subjects on the basis of odd or novel ideation and decreased conscientiousness.     

Use of the five-factory inventory in characterizing patients with major depressive disorder

Research on personality traits has suggested an association between depression and certain personality traits, such as neuroticism and extraversion. Costa and McCrae's five-factor personality inventory (NEO) has been shown to measure personality traits in a nonclinical population, but its use has not been fully explored in clinical populations. This study aims to compare NEO results in a sample of depressed outpatients with published test norms, and determine if different levels of neuroticism and extraversion are associated with differences in certain psychosocial and clinical characteristics. Seventy-six depressed outpatients participating in antidepressant clinical trials completed this self-report questionnaire before beginning pharmacological treatment. Diagnosis of major depressive disorder (MDD) was made using the Structured Clinical Interview for DSM-III-R or DSM-IV and the severity of depression was measured with the 17-item Hamilton Depression Rating Scale (HAM-D). The three analyses conducted were as follows: (1) NEO factor scores were compared with published normative means; (2) three groups, based on level of neuroticism, were compared on certain psychosocial and clinical characteristics; and (3) three groups, based on level of extraversion, were compared on the same psychosocial and clinical characteristics. Both the males and females obtained T score values for the Neuroticism Scale 1.5 SD above the mean, for the Extraversion Scale 1.5 SD below the mean, and for the Conscientiousness Scale 1.5 SD below the mean. No significant differences were found between subjects with different levels of neuroticism and extraversion, although a trend did exist indicating a positive relationship between neuroticism and severity of depression. Depressed outpatients experience frequent negative affects, have irrational thought processes, cope with stress poorly, have difficulty controlling impulses, prefer to be alone, and have difficulty carrying out tasks. Future studies should examine how such personality factors affect response to treatment and course of illness.     

Personality traits of women with a history of childhood sexual abuse

This study examined relationships between specific dimensions of childhood sexual abuse and personality traits in adulthood. Study participants were 74 hospitalized female psychiatric patients with a self-reported history of childhood sexual abuse. Characteristics of childhood sexual abuse were obtained from a structured life-events interview. Personality was measured with the NEO-Five-Factor Inventory (NEO-FFI), which yields scores on neuroticism, extraversion, openness to experience, agreeableness, and conscientiousness. We hypothesized that parental abuse, intercourse, and the combination of these two childhood sexual abuse characteristics would be associated with personality traits. Supporting this hypothesis, women who were abused by a parent had lower scores on openness to experience than women who were abused by someone else. Patients whose abuse history included both parental abuse and intercourse had very low extraversion scores. Our findings suggest that there are associations between personality traits and childhood sexual abuse characteristics in psychiatric patients. Specifically, women who experienced intercourse by a parent may be more introverted and less open to experience than women whose sexual abuse history does not include parental incest.     

Personality and diabetes mellitus incidence in a national sample

Objective

To test whether personality traits were prospectively associated with type 2 diabetes incidence.

Methods

The sample (n = 6798) was derived from the National Health and Nutrition Examination Survey Epidemiological Follow-up Study cohort. We fit four logistic regression models to test whether neuroticism, extraversion, openness to experience, or the Type A behavior pattern predicted type 2 diabetes incidence. Model 1 included sex, age, and race/ethnicity. Model 2 added personality traits, Model 3 added depressive symptoms, and Model 4 added body mass index (BMI), hypertension, and cigarette smoking status as predictors.

Results

In Model 1 age was associated with increased risk of diabetes (2% per year); being black as opposed to white was associated with a three-fold increase in risk. In Model 2 age and being black were still significant and extraversion was associated with decreased risk (17% per standard deviation [SD]). In Model 3 age, being black, and extraversion were still significant. In addition, neuroticism was associated with decreased risk (26% per SD) and depressive symptoms were associated with increased risk (28% per SD). In Model 4 age, being black, neuroticism, and depressive symptoms were still significant. BMI was associated with increased risk (14% per SD) and extraversion was no longer significant.

Conclusions

Higher neuroticism was associated with reduced type 2 diabetes risk even after controlling for race/ethnicity, age, depressive symptoms, and BMI. Extraversion and Type A behavior were not significant after including covariates.