Clobazam and diazepam: The differential effects on psychomotor performance and subjective feelings in normal volunteers with high neuroticism level

The purpose of this study was to investigate the possible differences between diazepam and clobazam with regard to their effects on psychomotor performance and subjective feeling in normal volunteers with high neuroticism levels. The study was designed as a double-blind, crossover, single-dose comparison of clobazam, diazepam, and placebo. Using the Maudsley Personality Inventory (MPI), 12 healthy male volunteers exhibiting high neuroticism scores were selected. Clobazam 10 mg, diazepam 5 mg, and placebo were administered orally. Measurements of psychomotor performance and subjective ratings of mood states were performed before and 1.5 and 6 hr after administration. Prior to the experiment the subjects were trained with the performance tests to minimize interference of learning effects with drug effects. Between the three treatments there were 1-wk intervals. Both clobazam and diazepam significantly lowered choice-reaction task performance as compared to placebo. Only clobazam lowered mirror-drawing task performance significantly differently from placebo. Significant changes in subjectively rated mood states were also seen after clobazam only. These mood changes appeared to indicate some disinhibitory or stimulant effects. The demonstrated differences between the effects of both anxiolytics are discussed in the context of experimental design characteristics and the subjects' high level of neuroticism. Some of the observed effects may be due to an interaction of drug effects with neurotic tendencies rather than to generalized drug effects per se.     

Neuroticism and Negative Urgency in Problematic Alcohol Use: A Pilot Study

Background: Problematic alcohol use is common among university students and personality might account for individual differences in developing this maladaptive behavior. Two personality dispositions implicated in problematic alcohol use are negative urgency and neuroticism. However, the relationship of these traits to problematic alcohol use is unclear. In college students high neuroticism is not directly linked to problematic alcohol use. On the other hand, the experience of emotional distress in people high in neuroticism could impair the capacity for impulse control. Loss of impulse control under conditions of negative affect could trigger impulsive drinking and problematic alcohol use in the long run. Objectives: We investigated this idea by testing whether negative urgency mediates the relationship of neuroticism to problematic alcohol use. Methods: Participants were 60 undergraduate university students who completed the Urgency subscale of the Urgency, (lack of) Premeditation, (lack of) Perseverance, Sensation Seeking, and Positive Urgency Impulsive Behaviour scale (UPPS-P), the Alcohol Use Disorders Identification Test (AUDIT), and the Neuroticism subscale of the Eysenck Personality Questionnaire Revised short form (EPQ-RSS). Results: The results confirmed our hypothesis as we found an indirect effect of negative urgency on the relationship between neuroticism and problematic alcohol use. Conclusions/Importance: It appears that it is not distress but the tendency to act rashly when distressed that is important in developing problematic alcohol drinking in university students.     

Migraine, Personality, and Psychiatric Comorbidity

The purpose of this report is to examine the association between migraine and personality, taking into account history of co-occurring psychiatric disorders. Data came from an epidemiologic study of young adults in the Detroit, Michigan metropolitan area. Migraine, defined according to 1988 IHS criteria, and major depression and anxiety disorders were ascertained by a structured diagnostic interview. Migraine was associated with neuroticism, but not with extraversion or psychoticism, measured by the Eysenck's Personality Questionnaire. The association remained significant, when sex and history of major depression and anxiety disorders were controlled. An excess of 25% of persons with migraine alone, uncomplicated by psychiatric comorbidity, scored in the highest quartile of neuroticism. The results suggest that migraine sufferers might be more vulnerable to psychopathology and poor adjustment to their medical condition.     

Mood,neuroticism, and the encoding of affective words

A lexical decision task, with words of positive, neutral and negative content, was used to test for affective bias in word encoding. Bias in priming of response was also examined; stimulus onset asynchrony (SOA) between prime and target words was manipulated to distinguish automatic and controlled priming. We tested for bias associated with emotional content of words, and with trait and state subject characteristics of neuroticism and pleasantness of mood. Results showed a variety of biases, but mood-congruence of priming of emotional words was found only in subjects selected for relatively extreme moods. In unprimed lexical decision, the strongest effect was a general processing advantage for negative words, although some variation between subject groups was found. Negative word-pairs also showed greater automatic priming magnitude than positive word pairs. Neutral words were more strongly primed in more neurotic subjects. The magnitude of controlled priming was greater for both types of emotional word than for neutral words. Implications of the results for spreading activation and attentional models of affective bias are discussed. It is concluded that there is a general, automatic processing advantage for negative words, but the tuning of the information-processing system to affective content varies with neuroticism and mood. Results are broadly consistent with hybrid models of affective bias, which propose that mood-congruence is influenced by several distinct mechanisms.     

Vegetarianism,depression, and the five factor model of personality

This study investigated whether vegetarians and omnivores differ in their personality characteristics. We measured the five factor model of personality and depressive symptoms in vegetarians, who avoided meat and fish (n = 276); semi-vegetarians, who ate some meat and/or fish (n = 1191); and omnivores (n = 4955). Although vegetarians and semi-vegetarians were more open to new experiences, they were more neurotic and depressed than omnivores. Neither conscientiousness nor agreeableness varied as a function of dietary habits. These findings contribute to our understanding about differences between vegetarians’ and omnivores’ personalities, which might help us better understand individual differences in food preferences.     

Predictors of subjective ratings of stressor severity: the effects of current mood and neuroticism

Respondent‐based or subjective, ratings of stressor severity are posited to be influenced by systematic biases related to current mood and trait neuroticism which may confound associations between environmental stressors and psychological outcomes. The current study examined the effects of current mood state and neuroticism on subjective ratings of severity for real‐life stressors in a sample of 76 (30 males) undergraduates. Subjective ratings of stressor severity were collected in the context of an interview‐based stress assessment and were assessed on two separate occasions. Changes in mood state across the two assessments did not correspond with changes in subjective ratings of stressor severity. Neuroticism independently predicted subjective ratings of stressor severity, as did female gender and investigator‐based ratings of objective stressor severity. In addition, there was evidence to suggest that neuroticism fully accounted for observed associations between current mood state and subjective ratings of stressor severity. The findings are discussed with regard to the potential confounding influence of neuroticism in studies that rely on respondent‐based ratings of stressor severity in predicting psychological outcomes. Copyright © 2010 John Wiley & Sons, Ltd.     

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.     

A novel differential susceptibility gene: CHRNA4 and moderation of the effect of maltreatment on child personality

Background: The differential susceptibility hypothesis states that some genetic variants that confer risk in adverse environments are beneficial in normal or nurturing environments. The cholinergic system is promising as a source of susceptibility genes because of its involvement in learning and neural plasticity. The cholinergic receptor gene CHRNA4 has been linked to characteristics related to the personality traits Neuroticism and Openness/Intellect. Methods: The effects of interaction between CHRNA4 genotype and maltreatment status on child personality were examined in a well matched sample of 339 maltreated and 275 non‐maltreated children (aged 8–13 years). Results: Variation in CHRNA4 interacted with childhood maltreatment to predict personality in a manner indicating differential susceptibility. The interaction of CHRNA4 and maltreatment status predicted Neuroticism and Openness/Intellect. Maltreated children with the rs1044396 T/T genotype scored highest on Neuroticism and showed no effect of genotype on Openness/Intellect. Non‐maltreated children with this genotype scored lowest on Neuroticism and highest on Openness/Intellect. Conclusion: Variation in CHRNA4 appears to contribute to personality by affecting degree of developmental sensitivity to both normal and adverse environments.     

Relationship between the NEO Personality Inventory Revised neuroticism scale and prospectively reported negative affect across the menstrual cycle

Previous research has suggested a possible link between neuroticism and premenstrual symptom changes. Results, however, are difficult to interpret given methodological problems such as retrospective reporting of premenstrual symptoms, and failure to control for the generalized influence of neuroticism on psychosomatic symptomatology. The present study aimed to address these issues.

One hundred and nine women from the general population completed the modified Menstrual Distress Questionnaire daily for 70 days. Neuroticism was assessed using the NEO Personality Inventory Revised.

Neuroticism accounted for a significant amount of variation in premenstrual negative affect both before and after controlling for baseline (follicular) symptom levels. The relationship between neuroticism and premenstrual negative affect could not be linked to any particular facet of neuroticism (e.g. anxiety, depression). Oral contraceptive (OC) users had significantly higher levels of neuroticism than the non-oral contraceptive (NOC) group. A significant interaction between OC use and menstrual cycle phase was also noted, with a trend toward OC users experiencing less premenstrual, but more menstrual, negative affect compared with the NOC group.

The results are discussed in terms of the contribution of personality factors to the etiology of premenstrual change, and the utility of cognitive-behavioral treatment approaches.