The relationship of neuroticism and extraversion to symptoms of anxiety and depression in the general population

Few studies have investigated the relationship of the personality dimensions of neuroticism and extraversion to the symptoms of depression and anxiety in the general population. A random general population sample (ages 20-70 years), from two Finnish cities was surveyed with the Eysenck Personality Inventory (EPI), Beck Depression Inventory (BDI), and Beck Anxiety Inventory (BAI). In addition, questions regarding diagnosed lifetime mental disorders, health care use for psychiatric reasons in the past 12 months, and history of mental disorders in first-degree relatives were posed. Among the 441 subjects who participated, neuroticism correlated strongly with symptoms of depression (r(s)=.71, P<.001) and anxiety (r(s)=.69, P<.001), and somewhat with self-reported lifetime mental disorder (r(s)=.30, P<.001) and health care use for psychiatric reasons in the past 12 months (r(s)=.24, P<.001). Extraversion correlated negatively with symptoms of depression (r(s)=-.47, P<.001), anxiety (r(s)=-.36, P<.001), self-reported lifetime mental disorder (r(s)=-.17, P<.001), and health care use for psychiatric reasons in the past 12 months (r(s)=-.14, P=.004). In multiple regression models, even after adjusting for gender, age, and education, BDI scores were significantly associated with neuroticism, extraversion, and age, whereas BAI scores were associated only with neuroticism. Neuroticism is strongly associated with depressive and anxiety symptoms, and intraversion is moderately associated with depressive symptoms in the urban general population. The relationship of these personality dimensions to both self-reported lifetime mental disorders and use of health services for psychiatric reasons strengthens the clinical validity of these personality dimensions.     

Resting brain metabolic correlates of neuroticism and extraversion in young men

Neuroticism and extraversion are two core dimensions of personality and are considered to be associated with emotional disorders. We investigated resting state brain metabolic correlates of neuroticism and extraversion using a positron emission tomography. Twenty healthy young men completed an F-flurodeoxyglucose-PET scan at rest and the Korean version of the revised Eysenck Personality Questionnaire. Neuroticism was negatively correlated with regional glucose metabolism in prefrontal regions including the medial prefrontal cortex. Extraversion was positively correlated with metabolism in the right putamen. These results suggest close associations between resting state brain activity in the prefrontal and striatal regions and specific personality traits and thus contribute to the understanding of the neurobiological bases of predisposition to psychiatric disorders.     

Prefrontal cortex glutamate and extraversion

Extraversion is considered one of the core traits of personality. Low extraversion has been associated with increased vulnerability to affective and anxiety disorders. Brain imaging studies have linked extraversion, approach behaviour and the production of positive emotional states to the dorsolateral prefrontal cortex (DLPFC) and glutamatergic neurotransmission. However, the relationship between extraversion and glutamate in the DLPFC has not been investigated so far. In order to address this issue, absolute glutamate concentrations in the DLPFC and the visual cortex as a control region were measured by 3-Tesla proton magnetic resonance spectroscopy (1H-MRS) in 29 subjects with high and low extraversion. We found increased glutamate levels in the DLPFC of introverts as compared with extraverts. The increased glutamate concentration was specific for the DLPFC and negatively associated with state anxiety. Although preliminary, results indicate altered top-down control of DLPFC due to reduced glutamate concentration as a function of extraversion. Glutamate measurement with 1H-MRS may facilitate the understanding of biological underpinnings of personality traits and psychiatric diseases associated with dysfunctions in approach behaviour and the production of positive emotional states.     

Personality modulates the effects of emotional arousal and valence on brain activation

The influence of personality on the neural correlates of emotional processing is still not well characterized. We investigated the relationship between extraversion and neuroticism and emotional perception using functional magnetic resonance imaging (fMRI) in a group of 23 young, healthy women. Using a parametric modulation approach, we examined how the blood oxygenation level dependent (BOLD) signal varied with the participants' ratings of arousal and valence, and whether levels of extraversion and neuroticism were related to these modulations. In particular, we wished to test Eysenck's biological theory of personality, which links high extraversion to lower levels of reticulothalamic-cortical arousal, and neuroticism to increased reactivity of the limbic system and stronger reactions to emotional arousal. Individuals high in neuroticism demonstrated reduced sustained activation in the orbitofrontal cortex (OFC) and attenuated valence processing in the right temporal lobe while viewing emotional images, but an increased BOLD response to emotional arousal in the right medial prefrontal cortex (mPFC). These results support Eysenck's theory, as well as our hypothesis that high levels of neuroticism are associated with attenuated reward processing. Extraversion was inversely related to arousal processing in the right cerebellum, but positively associated with arousal processing in the right insula, indicating that the relationship between extraversion and arousal is not as simple as that proposed by Eysenck.     

Cortisol and adrenocorticotropic hormone responses to naloxone in subjects with high and low neuroticism.

BACKGROUND: Neuroticism is a highly heritable personality trait that is a risk factor for certain affective and anxiety disorders. Studies link neuroticism with alterations in the Hypothalamic-Pituitary-Adrenal (HPA) stress response. We interrogated HPA axis dynamics as a function of neuroticism, employing the opioid receptor antagonist, naloxone. METHODS: Subjects were assigned to either high or low neuroticism groups on the basis of Revised Neuroticism, Extraversion, Openness Personality Inventory (NEO-PI-R) scores and received naloxone hydrochloride (0, 125 microg/kg, and 375 microg/kg). Serum adrenocorticotropic hormone (ACTH) and cortisol levels were monitored. RESULTS: Significant, dose-dependent differences in cortisol response were observed between neuroticism groups, whereas no differences were observed in ACTH. The low neuroticism group demonstrated a dose-dependent cortisol response with a plateau at the 125 microg/kg dose of naloxone. In contrast, the high neuroticism group demonstrated a graded cortisol response to all doses of naloxone. CONCLUSIONS: These findings show that neuroticism is associated with altered cortisol responses to opioid receptor blockade, suggesting that alterations in HPA axis function already exist in persons at increased risk for certain depressive and anxiety disorders.     

Anxiety,neuroticism and oxidative stress: Cross‐sectional study in non‐smoking college students

Aims: Oxidative stress has gained attention recently in psychiatric medicine and has been reported to be associated with various diseases. However, the psychosocial factors involved in oxidative stress are still not well understood. Thus, the aim of this study was to examine whether anxiety levels and neuroticism were associated with serum oxidative and anti‐oxidative status in healthy college students. Methods: Participants in this cross‐sectional study were 54 non‐smoking college students. Their serum oxidative status was determined by reactive oxygen metabolites (ROM) and the biological anti‐oxidant potential. Anxiety levels and neuroticism were assessed using the State–Trait Anxiety Inventory and the NEO Five‐Factor Inventory, respectively. Results: Correlation analysis showed an association of increased ROM concentration with elevated anxiety levels (State, ρ = 0.39, P = 0.046; Trait, ρ = 0.44, P = 0.024) and the personality trait of neuroticism (ρ = 0.47, P = 0.016) in female students. However, the ROM concentration in male students was not associated with the anxiety level or any personality trait. Conclusion: Although these findings suggest that neurotic and anxious female students tend to be exposed to oxidative stress, these linkages should be confirmed by multivariate analysis in future research.     

A polymorphism of the beta1-adrenergic receptor is associated with low extraversion.

BACKGROUND: We examined the possibility that allelic variation leading to alterations in beta(1)-adrenergic function might be present in persons with elevated social anxiety-related traits. METHODS: A sample of 504 undergraduate college students were phenotyped on a personality inventory (the NEO-Personality Inventory-Revised) and measures of shyness and social anxiety and genotyped for two beta(1) adrenergic (ADRB1 gene) polymorphisms: a serine/glycine substitution at amino acid 49 (Ser49Gly) and an arginine/glycine substitution at residue 389 (Arg389Gly). We hypothesized that the Gly49 variant (thought to be functional), but not variation at Arg389Gly, would be associated with (low) extraversion and shyness. We evaluated the potential for population stratification artifact by genotyping a set of 36 unlinked, highly polymorphic markers previously demonstrated to sufficiently distinguish the ancestry of major American populations. RESULTS: Presence of a Gly49 allele was associated with an increased odds of having low or very low extraversion (odds ratio = 1.68, 95% confidence interval 1.05-2.71). The Arg389Gly polymorphism, although in tight linkage disequilibrium (D' = -1.00) with Ser49Gly, was not significantly associated with level of extraversion. Formal testing showed that population structure did not explain the findings. CONCLUSIONS: The Ser49Gly functional polymorphism in the beta(1) adrenergic receptor might explain some of the population variance in extraversion and related personality traits. Population structure was excluded as an explanation for these findings. We used a sufficient marker set to exclude possible population stratification artifact. These findings should be replicated and extended to the study of psychiatric disorders marked by low extraversion, namely social phobia and other phobic disorders.     

Depression and neuroticism in multiple sclerosis

88 subjects (36 males and 52 females) affected by multiple sclerosis (MS), were studied with the CES-D and SRT tests for the evaluation of depressive reactions and neuroticism. Comparing the results with those of the control group, we found a significant score for depression and somatization in the MS patients, whereas the scores for anxiety and inadequacy were normal.

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Sommario Gli AA hanno eaminato 88 soggetti (36 maschi e 52 femmine) affetti da sclerosi multipla ai quali sono stati applicati i questionari del CES-D e SRT per la valutazione delle reazioni depressive e del nevroticismo. Dalla comparazione dei risultati con quelli del gruppo di controllo, emergono differenze statisticamente significative nella popolazione esaminata per quanto riguarda depressione e somatizzazione mentre i punteggi per ansia ed inadeguatezza risultano normali.

     

Implicit and explicit self-concept of neuroticism in borderline personality disorder

Purpose: In the past, research on personality in borderline personality disorder (BPD) used primarily questionnaires suggesting heightened neuroticism in BPD. Self-report instruments inform about the conscious or explicit self-concept. BPD patients are known to show negative distortion with exaggeration of negative affect in the self-report. Neuroticism represents a risk factor for mental disorders. Indirect measures are available that tap into the implicit self-concept of neuroticism. The implicit self-concept refers to individual differences in associative representations of the self. The present study examined for the first time the implicit in addition to the explicit self-concept of neuroticism in BPD.

Materials and methods: Female BPD patients (N?=?35) and healthy women (N?=?39) completed an implicit association test and the NEO-FFI personality inventory.

Results: BPD patients showed higher implicit and explicit neuroticism compared to controls. The group difference for explicit neuroticism was four times larger than that for implicit neuroticism. Presence of comorbid depressive disorder was positively correlated with implicit neuroticism. The IAT neuroticism showed excellent split-half reliability for BPD patients.

Conclusions: The present data suggest that BPD patients with comorbid clinical depression but not those without clinical depression differ from healthy individuals in their implicit self-concept of neuroticism. In the associative network, BPD patients with comorbid clinical depression exhibit stronger associations of the self with neuroticism-related characteristics, such as nervousness, fearfulness, and uncertainty than healthy individuals. Regardless of depression, BPD patients show increased explicit neuroticism. Our findings provide evidence that the IAT neuroticism can be applied reliably to BPD patients.     

Can personality traits help us explain disability in chronic schizophrenia?

Psychotic features have been considered the main determinant of psychosocial function in schizophrenia. However, other variables are likely to affect dysfunction in these patients. The authors' hypothesis is that personality traits in outpatients with chronic schizophrenia differ from traits found in the healthy population and may be associated with disability in this disorder. A total of 62 patients with schizophrenia were evaluated with the Eysenck Personality Questionnaire (EPQ) and the Tridimensional Personality Questionnaire (TPQ). Psychotic features were measured with the help of the Positive and Negative Syndrome Scale (PANSS). Disability was assessed with the Disability Assessment Schedule (DAS). A total of 43 healthy subjects were used as controls for personality measurements. Normative data for the study population was also used to evaluate results in patients. Patients with schizophrenia had higher levels of neuroticism (median in percentile 65) and lower levels of extraversion (median in percentile 25) than the healthy population. Results of the TPQ showed higher harm avoidance and lower reward dependence levels compared to the healthy population. After multiple regression tests, negative symptoms were the strongest predictor of disability in patients with schizophrenia. Neuroticism contributed independently to the DAS overall behavior and global judgement subscales scores (more negative symptoms and higher neuroticism resulted in worse functioning), but not to the social role subscale. Outpatients with chronic schizophrenia showed high levels of neuroticism, harm avoidance, and introversion. Neuroticism significantly contributes to the long-term deficits found in patients with schizophrenia.     

Neuroticism,introversion, and major depressive disorder—traits,states, or scars?

Background: The extent to which measures of the personality dimensions of neuroticism and introversion are influenced by symptoms of depression and anxiety or by episodes of depression, and whether neuroticism alone or both traits predispose one to depression remain unclear. Methods: Major depressive disorder patients (n=193) from the Vantaa Depression Study were interviewed at baseline and at 6 and 18 months, and a general population comparison group (n=388) was surveyed by mail. Patients' scores of neuroticism and extraversion‐introversion were compared between time points, and before and after a possible recurrence of depression between interviews. Patients' scores at an index interview, when the level of depression was lowest, were compared with scores of the general population, after controlling for anxiety and depression. Results: Among depressive patients, neuroticism scores declined (from 17.2, SD 3.7–13.7, SD 5.6, P<0.001) and extraversion scores increased (from 10.0, SD 4.7–11.2, SD 4.5, P<0.001) with recovery during follow‐up. The scores were not influenced by a recurrence of depression between measurements. In logistic regression, patients had higher neuroticism (odds ratio, OR 1.11, P=0.001) and lower extraversion (OR 0.92, P=0.003) than the general population. Conclusions: The overall level of neuroticism is markedly and introversion somewhat higher in depressive patients than in the general population. Anxiety symptoms have some, and depressive symptoms a strong influence on neuroticism scores, but only depression has an impact on introversion during a depressive episode. In medium‐term follow‐up, depressive episodes are unlikely to result in a personality scar persisting after recovery from an episode. Depression and Anxiety, 2009. © 2009 Wiley‐Liss, Inc.     

Abnormal brain tryptophan metabolism and clinical correlates in Tourette syndrome.

Symptoms in Tourette syndrome (TS) are likely related to abnormalities involving multiple neurotransmitter systems in striatal-thalamo-cortical circuitry. Although prior studies have found abnormal levels of tryptophan, serotonin, and their metabolites in blood, cerebrospinal fluid and brain tissue of TS patients, understanding of focal brain disturbances and their relationship to clinical phenotype remains poor. We used alpha-[(11)C]methyl-L-tryptophan (AMT) positron emission tomography (PET) to assess global and focal brain abnormalities of tryptophan metabolism and their relationship to behavioral phenotype in 26 children with TS and nine controls. Group comparisons on regional cortical and subcortical AMT uptake revealed decreased AMT uptake in bilateral dorsolateral prefrontal cortical and bilaterally increased uptake in the thalamus (P = 0.001) in TS children. The ratio of AMT uptake in subcortical structures to dorsolateral prefrontal cortex was significantly increased bilaterally (P < 0.01) in TS patients also. Behaviorally defined subgroups within the TS sample revealed differences in the pattern of AMT uptake in the fronto-striatal-thalamic circuit. This study demonstrates cortical and subcortical abnormalities of tryptophan metabolism in TS and provides neuroimaging evidence for a role of serotonergic mechanisms in the pathophysiology of TS.     

Associations of mindfulness with depressive symptoms and well-being in older adults: the moderating role of neuroticism

Objective: To investigate whether observed interactions of mindfulness with the personality trait neuroticism extend to older adults and to aspects of psychological functioning other than depressive symptoms, and whether effects of mindfulness training in this population depend on levels of neuroticism.

Method: We performed a secondary analysis of data from a randomized controlled trial of Mindfulness-Based Stress Reduction (MBSR) for community-dwelling older adults. We investigated whether neuroticism moderates associations of dispositional mindfulness with various aspects of psychological and physical functioning at baseline, as well as effects of MBSR on these outcomes.

Results: Significant two-way interactions showed that greater mindfulness was associated with fewer depressive symptoms and less negative affect at baseline in individuals with average or higher levels of neuroticism. In contrast, mindfulness was associated with greater positive affect and vitality and fewer physical symptoms regardless of the level of neuroticism. There were no effects of MBSR on these outcomes at any level of neuroticism.

Conclusion: Mindfulness may be more protective against psychological ill-being in older adults with higher levels of neuroticism, but conducive to positive psychological and physical well-being regardless of this personality trait. The potential moderating role of neuroticism should be further evaluated in studies of mindfulness-based interventions in older adults.     

Specific frequency bands of amplitude low‐frequency oscillation encodes personality

The biological model of extraversion and neuroticism identified by Eysenck has stimulated increasing interest in uncovering neurobiological substrate of the two fundamental dimensions. Here we aim to explore brain disturbances underlying extraversion and neuroticism in 87 healthy individuals using fractional amplitude of low‐frequency fluctuations (LFF) on resting‐state functional magnetic resonance imaging. Two different frequency bands, Slow‐5 (0.01–0.027 Hz) exhibiting higher power and involving larger brain regions, and Slow‐4 (0.027–0.073 Hz) exhibiting less power and emerging locally, were analyzed. Our results showed a positive correlation between LFF amplitude at Slow‐5 and extraversion in medial prefrontal cortex and precuneus, important portions of the default mode network, thus suggesting a link between default network activity and personality traits. LFF amplitude at Slow‐5 was correlated positively with neuroticism in right posterior portion of the frontal lobe, further validating neuroticism with frontal lateralization. In addition, LFF amplitude at Slow‐4 was negatively associated with extraversion and neuroticism in left hippocampus (HIP) and bilateral superior temporal cortex (STC) respectively, supporting the hypothesized (inverse) relationship between extraversion and resting arousal, also implying neural circuit underlying emotional process influencing on personality. Overall, these findings suggest the important relationships, between personality and LFF amplitude dynamic, depend on specific frequency bands. Hum Brain Mapp 35:331–339, 2014. © 2012 Wiley Periodicals, Inc.     

Personality and suicidal ideation in the elderly: factorial invariance and latent means structures across age

Objectives: Suicide among the elderly is a dramatic global health problem. Although fatal attempts are frequent in the elderly, research indicated that they rarely present long-term elaboration of suicidal ideation and communicate their intents. Consequently, risk factor detection and assessment are salient. Although evidence on the association between personality and suicidal ideation in young adults is accumulating, little is known about its relevance in the elderly. The purpose of the present study was to analyze the components of a measurement model that are invariant across young adults and older adults and then investigate the relations among dimensions of personality and suicide risk. We postulated a specific relation pattern a priori and tested the hypotheses statistically in order to examine the models for equivalency of the factorial measurement.

Method: We investigated 316 young adults and 339 older adults, who were administered self-report questionnaires to assess depression, hopelessness, alternative five-factor model of personality, and self–other perception.

Results: Multigroup confirmatory factor analyses were conducted, yielding a final model with excellent fit to the data. This model showed a similar pattern of associations between suicidal ideation and personality across both groups.

Conclusions: Although the elderly are exposed to specific life stressors associated with suicidal ideation, our findings suggest that the elderly and young adults may be similar on personality and psychopathology variables predicting suicidal ideation than previously hypothesized. Implications are provided for enhanced assessment and intervention of the elderly high in neuroticism, depression, hopelessness, and with negative self–other perception.     

Regional brain glucose metabolism in drug free schizophrenic patients and clinical correlates

Regional brain glucose metabolism was investigated in healthy volunteers (n = 10) and in drug free schizophrenic patients (n = 20). The metabolism was determined by positron emission tomography (PET) with 11C-glucose as the tracer. Diagnosis of schizophrenia was made according to RDC and DSM III. Eight patients had their first psychotic episode, four patients had a subchronic course and eight patients had a chronic course with an exacerbation of their illness. Computed tomography (CT) of the brain were made in all the subjects. Regions of interest (n = 35) were drawn on displayed CT images and the marked regions were transferred to the corresponding slice of the PET examination. The PET investigation was made in a dimly lit, quiet room with the eyes of the subject covered. The time course of the 11C-glucose uptake was measured by a four ring PET scanner (PC-384-7B). Metabolic rates of glucose varied greatly among the schizophrenic patients investigated. The variance was significantly greater than that of the controls in most regions. Decreases in mean levels of metabolic rates were related to patients with subchronic or chronic courses. Changes in metabolism were not related to previous duration of neuroleptic treatment of the patients. Left-right asymmetries were found in the temporal lobe (area 22) and the basal frontal cortex (area 11), the metabolic rates of the patients being lower on the left side compared to the controls. Asymmetry of the metabolic rate of the amygdala in hebephrenic patients was the opposite of that found in paranoid patients and controls. Negative correlations between regional metabolic rates and autistic or negative symptoms were found. Thus, the lower the metabolic rate was, the more autistic the patient. Metabolic rates were not correlated to atrophic changes of the brain. No basis for a specific alteration in frontal cortical metabolism of schizophrenics was obtained. Changes in regional metabolic rates in schizophrenia are suggested to reflect disturbances in more general mechanisms which are of importance in neuronal function.