Transporter-facilitated uptake of serotonin (5-hydroxytryptamine or 5-HT) has been implicated in anxiety in humans and animal models and is the site of action of widely used uptake-inhibiting antidepressant and antianxiety drugs. Human 5-HT transporter (5-HTT) gene transcription is modulated by a common polymorphism in its upstream regulatory region. The short variant of the polymorphism reduces the transcriptional efficiency of the 5-HTT gene promoter, resulting in decreased 5-HTT expression and 5-HT uptake in lymphoblasts. Association studies in two independent samples totaling 505 individuals revealed that the 5-HTT polymorphism accounts for 3 to 4 percent of total variation and 7 to 9 percent of inherited variance in anxiety-related personality traits in individuals as well as sibships.

Clinical, field, and experimental studies of response to potentially stressful life events give concordant findings: there is a general human tendency to undergo episodes of intrusive thinking and periods of avoidance. A scale of current subjective distress, related to a specific event, was based on a list of items composed of commonly reported experiences of intrusion and avoidance. Responses of 66 persons admitted to an outpatient clinic for the treatment of stress response syndromes indicated that the scale had a useful degree of significance and homogeneity. Empirical clusters supported the concept of subscores for intrusions and avoidance responses.

We performed a quantitative review of associations between the higher order personality traits in the Big Three and Big Five models (i.e., neuroticism, extraversion, disinhibition, conscientiousness, agreeableness, and openness) and specific depressive, anxiety, and substance use disorders (SUD) in adults. This approach resulted in 66 meta-analyses. The review included 175 studies published from 1980 to 2007, which yielded 851 effect sizes. For a given analysis, the number of studies ranged from three to 63 (total sample size ranged from 1,076 to 75,229). All diagnostic groups were high on neuroticism (mean Cohen's d = 1.65) and low on conscientiousness (mean d = -1.01). Many disorders also showed low extraversion, with the largest effect sizes for dysthymic disorder (d = -1.47) and social phobia (d = -1.31). Disinhibition was linked to only a few conditions, including SUD (d = 0.72). Finally, agreeableness and openness were largely unrelated to the analyzed diagnoses. Two conditions showed particularly distinct profiles: SUD, which was less related to neuroticism but more elevated on disinhibition and disagreeableness, and specific phobia, which displayed weaker links to all traits. Moderator analyses indicated that epidemiologic samples produced smaller effects than patient samples and that Eysenck's inventories showed weaker associations than NEO scales. In sum, we found that common mental disorders are strongly linked to personality and have similar trait profiles. Neuroticism was the strongest correlate across the board, but several other traits showed substantial effects independent of neuroticism. Greater attention to these constructs can significantly benefit psychopathology research and clinical practice.

In this review, we evaluate four topics in the study of personality development where discernible progress has been made since 1995 (the last time the area of personality development was reviewed in this series). We (a) evaluate research about the structure of personality in childhood and in adulthood, with special attention to possible developmental changes in the lower-order components of broad traits; (b) summarize new directions in behavioral genetic studies of personality; (c) synthesize evidence from longitudinal studies to pinpoint where and when in the life course personality change is most likely to occur; and (d) document which personality traits influence social relationships, status attainment, and health, and the mechanisms by which these personality effects come about. In each of these four areas, we note gaps and identify priorities for further research.

Decision making and risk taking are interrelated processes that are important for daily functioning. The somatic marker hypothesis has provided a conceptual basis for processes involved in risk-taking decision making and has been used to link discrete neural substrates to risk-related behaviors. This investigation examined the hypothesis that the degree of risk-taking is related to the degree of activation in the insular cortex. Seventeen healthy, right-handed subjects performed a risk-taking decision-making task during functional magnetic resonance imaging (fMRI) using a fast event-related design. This investigation yielded three main findings. First, right insula (BA 13) activation was significantly stronger when subjects selected a "risky" response versus selecting a "safe" response. Second, the degree of insula activation was related to the probability of selecting a "safe" response following a punished response. Third, the degree of insula activation was related to the subjects' degree of harm avoidance and neuroticism as measured by the TCI and NEO personality questionnaires, respectively. These results are consistent with the hypothesis that insula activation serves as a critical neural substrate to instantiate aversive somatic markers that guide risk-taking decision-making behavior.

Two data sources--self-reports and peer ratings--and two instruments--adjective factors and questionnaire scales--were used to assess the five-factor model of personality. As in a previous study of self-reports (McCrae & Costa, 1985b), adjective factors of neuroticism, extraversion, openness to experience, agreeableness-antagonism, and conscientiousness-undirectedness were identified in an analysis of 738 peer ratings of 275 adult subjects. Intraclass correlations among raters, ranging from .30 to .65, and correlations between mean peer ratings and self-reports, from .25 to .62, showed substantial cross-observer agreement on all five adjective factors. Similar results were seen in analyses of scales from the NEO Personality Inventory. Items from the adjective factors were used as guides in a discussion of the nature of the five factors. These data reinforce recent appeals for the adoption of the five-factor model in personality research and assessment.

The personality trait of neuroticism refers to relatively stable tendencies to respond with negative emotions to threat, frustration, or loss. Individuals in the population vary markedly on this trait, ranging from frequent and intense emotional reactions to minor challenges to little emotional reaction even in the face of significant difficulties. Although not widely appreciated, there is growing evidence that neuroticism is a psychological trait of profound public health significance. Neuroticism is a robust correlate and predictor of many different mental and physical disorders, comorbidity among them, and the frequency of mental and general health service use. Indeed, neuroticism apparently is a predictor of the quality and longevity of our lives. Achieving a full understanding of the nature and origins of neuroticism, and the mechanisms through which neuroticism is linked to mental and physical disorders, should be a top priority for research. Knowing why neuroticism predicts such a wide variety of seemingly diverse outcomes should lead to improved understanding of commonalities among those outcomes and improved strategies for preventing them.

OBJECTIVE

Three potent risk factors for major depression are female sex, the personality trait of neuroticism, and adversity resulting from exposure to stressful life events. Little is known about how they interrelate in the etiology of depressive illness.

METHODS

In over 7,500 individual twins from a population-based sample, the authors used a Cox proportional hazard model to predict onsets of episodes of DSM-III-R major depression in the year before the latest interviews on the basis of previously assessed neuroticism, sex, and adversity during the past year; adversity was operationalized as the long-term contextual threat scored from 15 life event categories.

RESULTS

In the best-fit Cox model for prediction of depressive onsets, neuroticism, female sex, and greater adversity all strongly increased risk for major depression. An interaction was seen between neuroticism and adversity such that individuals with high neuroticism were at greater overall risk for major depression and were more sensitive to the depressogenic effects of adversity. An interaction was also seen between adversity and sex, as the excess risk for major depression in women was confined to individuals with low stress exposure.

CONCLUSIONS

Psychosocial adversity interacts both with neuroticism and with sex in the etiology of major depression. The impact of neuroticism on illness risk is greater at high than at low levels of adversity, while the effect of sex on probability of onset is the opposite--greater at low than at high levels of stress. Complete etiologic models for major depression should incorporate interactions between risk factor classes.

A self-administered questionary (the General Health Questionnaire) aimed at detecting current psychiatric disturbance was given to 553 consecutive attenders to a general practitioner's surgery. A sample of 200 of these patients was given an independent assessment of their mental state by a psychiatrist using a standardized psychiatric interview. Over 90% of the patients were correctly classified as "well" or "ill" by the questionary, and the correlation between questionary score and the clinical assessment of severity of disturbance was found to be +0.80.The "conspicuous psychiatric morbidity" of a suburban general practice assessed by a general practitioner who was himself a psychiatrist and validated against independent psychiatric assessment was found to be 20%. "Hidden psychiatric morbidity" was found to account for one-third of all disturbed patients. These patients were similar to patients with "conspicuous illnesses" in terms both of degree of disturbance and the course of their illnesses at six-month follow-up, but were distinguished by their attitude to their illness and by usually presenting a physical symptom to the general practitioner.When 87 patients who had been assessed as psychiatric cases at the index consultation were called back for follow-up six months later, two-thirds of them were functioning in the normal range. Frequency of attendance at the surgery in the six months following index consultation was found to have only a modest relationship to severity of psychiatric disturbance.It is argued that minor affective illnesses and physical complaints often accompany each other and usually have a good prognosis.

Three studies are reported that examine the relations between personality and happiness or subjective well-being. It is argued that (a) one set of traits influences positive affect or satisfaction, whereas a different set of traits influences negative affect or dissatisfaction; (b) the former set of traits can be reviewed as components of extraversion, and the latter as components of neuroticism; and (c) personality differences antedate and predict differences in happiness over a period of 10 years, thus ruling out the rival hypothesis that temporary moods or states account for the observed relations. A model of individual differences in happiness is presented, and the separate and complementary roles of trait and adaptation-level theories in explaining happiness are discussed.

A self-report inventory for the assessment of mindfulness skills was developed, and its psychometric characteristics and relationships with other constructs were examined. Participants included three samples of undergraduate students and a sample of outpatients with borderline personality disorder Based on discussions of mindfulness in the current literature, four mindfulness skills were specified: observing, describing, acting with awareness, and accepting without judgment. Scales designed to measure each skill were developed and evaluated. Results showed good internal consistency and test-retest reliability and a clear factor structure. Most expected relationships with other constructs were significant. Findings suggest that mindfulness skills are differentially related to aspects of personality and mental health, including neuroticism, psychological symptoms, emotional intelligence, alexithymia, experiential avoidance, dissociation, and absorption.

BACKGROUND

Prior studies suggest that the personality traits of neuroticism and extroversion may be related to the liability to major depression (MD).

OBJECTIVE

To clarify the magnitude and nature of the association between neuroticism and extroversion and the risk for MD.

METHODS

Longitudinal population-based twin cohort.

METHODS

General community.

METHODS

A total of 20 692 members of same-sex twin pairs from the population-based Swedish Twin Registry who completed a self-report questionnaire assessing neuroticism and extroversion in 1972 and 1973 and were personally interviewed for lifetime history of MD more than 25 years later.Main Outcome Measure Lifetime history of modified DSM-IV MD.

RESULTS

Levels of neuroticism strongly predicted the risks for both lifetime and new-onset MD. Twin modeling indicated that the association between neuroticism and MD resulted largely from shared genetic risk factors, with a genetic correlation of +0.46 to +0.47. Levels of extroversion were weakly and inversely related to the risks for lifetime and new-onset MD. This effect disappeared when we controlled for the level of neuroticism. Twin modeling produced similar results.

CONCLUSIONS

Results from both longitudinal and genetic analyses support the hypothesis that neuroticism strongly reflects the liability to MD. This association arises largely because neuroticism indexes the genetic risk for depressive illness. However, substantial proportions of the genetic vulnerability to MD are not reflected in neuroticism. By contrast, extroversion is only weakly related to risk for MD.

Positive and negative affect, measured by the Bradburn Affect Balance Scale, were studied in a longitudinal sample spanning from 1971 to 1994. The sample (N = 2,804) represented 4 generations of families. Linear trend analyses compared generations over time for positive and negative affect and also examined the possible influences of neuroticism and extraversion on initial levels of affect and patterns of change in affect. Negative affect decreased with age for all generations, although the rate was attenuated among the oldest adults. Higher neuroticism scores also attenuated the decrease in negative affect across time. For positive affect, the younger and middle-aged adults showed marked stability, but the older group evidenced a small decrease over time. Higher levels of extraversion were related to more stability in positive affect.

BACKGROUND

Several prior studies have found reduced hippocampal volume in victims of psychological trauma with post-traumatic stress disorder (PTSD). We were interested to determine if this finding was evident in women who were victimized by severe sexual abuse in childhood.

METHODS

In this study, hippocampal volume was measured using quantitative magnetic resonance imaging (MRI) in 21 women who reported being severely sexually abused in childhood and 21 socio-demographically similar women without abuse histories.

RESULTS

Women who reported sexual victimization in childhood had significantly reduced (5% smaller) left-sided hippocampal volume compared to the non-victimized women. Hippocampal volume was also smaller on the right side, but this failed to reach statistical significance. Left-sided hippocampal volume correlated highly (rs = -0.73) with dissociative symptom severity, but not with indices of explicit memory functioning.

CONCLUSIONS

These findings, which are generally consistent with prior reports of reduced hippocampal volume in combat veterans with PTSD, suggest that diminished hippocampal size may be either a consequence of trauma exposure or a risk factor for the development of psychiatric complications following trauma exposure. The observed relationship between symptom severity and hippocampal volume suggests that mesial temporal lobe dysfunction may directly mediate certain aspects of PTSD and dissociative disorder symptomatology.

OBJECTIVE

The anxiety and depressive disorders exhibit high levels of lifetime comorbidity with one another. The authors examined how genetic and environmental factors shared by the personality trait neuroticism and seven internalizing disorders may help explain this comorbidity.

METHODS

Lifetime major depression, generalized anxiety disorder, panic disorder, agoraphobia, social phobia, animal phobia, situational phobia, and neuroticism were assessed in over 9,000 twins from male-male, female-female, and opposite-sex pairs through structured diagnostic interviews. Multivariate structural equation models were used to decompose the correlations between these phenotypes into genetic and environmental components, allowing for sex-specific factors.

RESULTS

Genetic factors shared with neuroticism accounted for between one-third and one-half of the genetic risk across the internalizing disorders. When nonsignificant gender differences were removed from the models, the genetic correlations between neuroticism and each disorder were high, while individual-specific environmental correlations were substantially lower. In addition, the authors could identify a neuroticism-independent genetic factor that significantly increased risk for major depression, generalized anxiety disorder, and panic disorder.

CONCLUSIONS

There is substantial, but not complete, overlap between the genetic factors that influence individual variation in neuroticism and those that increase liability across the internalizing disorders, helping to explain the high rates of comorbidity among the latter. This may have important implications for identifying the susceptibility genes for these conditions.

We discuss the relation between personality factors and two adult forms of disinhibitory psychopathology--alcohol abuse or dependence and antisocial personality disorder. First, we briefly review various methodological issues relevant to research in this area. Next, we review empirical findings relating three broad-band personality trait dimensions neuroticism/emotionality, impulsivity/disinhibition, extraversion/sociability) to both alcohol abuse and dependence and antisocial personality disorder. Finally, theoretical models of the relationship between personality and each of these two disorders are presented. We conclude that although no single personality description is likely to be both a sensitive and specific indicator of either alcoholism or antisocial personality disorder, personality variables are important components of etiological models of these disorders.

The Geriatric Mental State and a new computerized diagnostic system, AGECAT, are briefly described. A nomenclature for designating cases for epidemiological work is introduced. Concordance between AGECAT and psychiatrists' diagnoses for these studies, hospital and community based (total of 541 subjects), achieved overall kappa values of 0.84 for a psychiatric hospital sample and 0.74 for a community sample. The values for depression and organic illness specifically in these settings were psychiatric hospital 0.80/0.86, and community 0.80/0.88, respectively.

1624 patients who were attending primary health facilities in 4 developing countries were examined to determine how many were suffering from mental disorder. Using stringent criteria to establish the presence of psychiatric morbidity, 225 cases were found, indicating an overall frequency of 13.9%. The great majority of cases were suffering from neurotic illnesses and for most the presenting complaint was of a physical symptom, such as headache, abdominal pain, cough or weakness. The health workers following their normal procedure correctly detected one third of the psychiatric cases.

A distinction between ruminative and reflective types of private self-attentiveness is introduced and evaluated with respect to L. R. Goldberg's (1982) list of 1,710 English trait adjectives (Study 1), the five-factor model of personality (FFM) and A. Fenigstein, M. F. Scheier, and A. Buss's (1975) Self-Consciousness Scales (Study 2), and previously reported correlates and effects of private self-consciousness (PrSC; Studies 3 and 4). Results suggest that the PrSC scale confounds two unrelated, motivationally distinct dispositions--rumination and reflection--and that this confounding may account for the "self-absorption paradox" implicit in PrSC research findings: Higher PrSC scores are associated with more accurate and extensive self-knowledge yet higher levels of psychological distress. The potential of the FFM to provide a comprehensive framework for conceptualizing self-attentive dispositions, and to order and integrate research findings within this domain, is discussed.