Preliminary confirmation of the proposed link between reward-dependence traits and norepinephrine

Personality and quality-of-life improvement after apomorphine infusion in Parkinson's disease

People with Parkinson's disease with motor fluctuations can be treated by continuous subcutaneous apomorphine infusion (CSAI) to reduce their symptoms. Nonetheless, factors are lacking to predict patients' quality-of-life amelioration after CSAI. This pilot study aimed to evaluate associations between personality dimensions and quality-of-life improvement after 6 months of CSAI. Thirty-nine people with Parkinson's disease awaiting CSAI were included. Linear regression models between 'Temperament and Character Inventory' personality dimensions at baseline and percentage of change in Parkinson's Disease Questionnaire-39 scores after 6 months of CSAI were realized (n = 35). The Temperament and Character Inventory was also compared between patients awaiting CSAI and patients awaiting deep brain stimulation of the sub-thalamic nucleus (n = 39 from the PREDI-STIM study). Higher reward dependence scores were associated with a better quality-of-life outcome after 6 months of CSAI, while self-directedness scores were associated with a better quality of life before CSAI (as opposed to harm avoidance, reward dependence and self-transcendence scores associated with a worse quality of life). Moreover, people with Parkinson's disease awaiting deep brain stimulation of the sub-thalamic nucleus had similar Temperament and Character Inventory dimensions compared to patients awaiting CSAI. People with Parkinson's disease with higher reward dependence scores at baseline had the best quality-of-life improvement after 6 months of CSAI. This finding could be used to better prepare and accompany people with Parkinson's disease during CSAI establishment. Moreover, this result could serve as an orientation factor to second-line treatments.

The relationship between novelty-seeking traits and behavior: Establishing construct validity for the human Behavioral Pattern Monitor

Novelty seeking is a tendency to approach new situations, putatively driven by the brain's catecholaminergic system. It is traditionally measured via self-report, but a laboratory-based paradigm, the human Behavioral Pattern Monitor (hBPM), quantifies behavior in a novel environment and has utility in cross-species studies of neuropsychiatric disorders. Our primary aim assessed whether self-reported novelty-seeking traits were associated with novelty-seeking behavior in the hBPM. An existing sample of 106 volunteers were categorized as high vs. low novelty seekers using the Temperament and Character Inventory (TCI). Subjects had been randomized to one dose of amphetamine (10 or 20 mg) or modafinil (200 or 400 mg), allowing us to explore whether a pharmacological catecholamine challenge further enhanced novelty-seeking behavior. High TCI novelty-seekers had more hBPM motor activity and novel object interactions. The exploratory analyses, although limited by low power, suggested that amphetamine and modafinil did not markedly moderate novelty-seeking traits. The hBPM demonstrates construct validity as a lab-based measure of novelty seeking and thus useful in translational studies of neuropsychiatric conditions and treatment options. Further research may illuminate whether a biological predisposition towards higher catecholaminergic activity, combined with the novelty-seeking trait, may increase propensity for risky and addictive behaviors.

Personality and brain contribute to academic achievements of medical students

There are many factors that influence the academic achievements of medical students, but how personality and brain modulate the academic achievements of medical students remains unclear. The study collected the personality, brain imaging, and academic data from 448 medical students at Tianjin Medical University with admission time between 2008 and 2017. Four types of academic achievements, including behavioral and social sciences, clinical sciences and skills, basic biomedical sciences, and scientific methods, were assessed by the academic records of 58 courses. Personality was evaluated by Tridimensional Personality Questionnaire and Neuroticism Extraversion Openness Personality Inventory. Brain structural and functional properties, including gray matter volume, spontaneous brain activity and functional connectivity, were computed based on magnetic resonance imaging (MRI). Linear regression was used to evaluate the associations between personality and academic achievements. A voxel-wise correlation was used to identify areas of the brain where structural and functional properties were associated with academic achievements. Mediation analysis was used to test whether brain properties and personality independently contribute to academic achievements. Our results showed that novelty seeking (NS) was negatively correlated, and conscientiousness was positively correlated with all types of academic achievements. Brain functional properties showed negatively correlated with academic achievement in basic biomedical sciences. However, we did not find any mediation effect of the brain functional properties on the association between personality (NS and conscientiousness) and academic achievement in basic biomedical sciences, nor mediation effect of the personality (NS and conscientiousness) on the association between brain functional properties and academic achievement in basic biomedical sciences. These findings suggest that specific personality (NS and conscientiousness) and brain functional properties independently contribute to academic achievements in basic biomedical sciences, and that modulation of these properties may benefit academic achievements among medical students.

Reward Dependence-Moderated Noradrenergic and Hormonal Responses During Noncompetitive and Competitive Physical Activities

The aim of this study was to reveal whether increased reward dependence (RD) plays a role in the catecholamine neurotransmitter release and testosterone hormone regulation during physical activities among healthy trained participants. Twenty-two male participants (mean age: 40.27 ± 5.4 years) participated in this study. Two conditions were constructed, namely, a noncompetitive and a competitive running task (RT), which were separated by a 2-week interval. Urine and blood samples were collected prior to and following the running tasks. Noradrenaline (NA), adrenaline (A), dopamine (D), and their metabolites, vanillylmandelic acid (VMA) and homovanillic acid (HVA), were measured from urine, while testosterone levels were analyzed from blood samples. RD was assessed using the Cloninger's Personality Inventory (PI). Mental health was evaluated using the WHO Well-Being, Beck Depression, and Perceived Life Stress Questionnaires. According to our findings, levels of NA, A, D, VMA, and testosterone released underwent an increase following physical exertion, independently from the competitive condition of the RT, while HVA levels experienced a decrease. However, we found that testosterone levels showed a significantly lower tendency to elevate in the competitive RT, compared with the noncompetitive condition (p = 0.02). In contrast, HVA values were higher in the competitive compared with the noncompetitive condition (p = 0.031), both before and after the exercise. Considering the factor RD, in noncompetitive RT, its higher values were associated with elevated NA levels (p = 0.007); however, this correlation could not be detected during the competitive condition (p = 0.233). Among male runners, the NA and testosterone levels could be predicted to the degree of RD by analyzing competitive and noncompetitive physical exercises.

Personality dimensions of patients can change during the course of parkinson's disease

BACKGROUND

Studies assessing personality dimensions by the "Temperament and Character Inventory" (TCI) have previously found an association between Parkinson's disease (PD) and lower Novelty Seeking and higher Harm Avoidance scores. Here, we aimed to describe personality dimensions of PD patients with motor fluctuations and compare them to a normative population and other PD populations.

METHODS

All PD patients awaiting Deep Brain Stimulation (DBS) answered the TCI before neurosurgery. Their results were compared to those of historical cohorts (a French normative population, a de novo PD population, and a PD population with motor fluctuations).

RESULTS

Most personality dimensions of our 333 included PD patients with motor fluctuations who are candidates for DBS were different from those of the normative population and some were also different from those of the De Novo PD population, whereas they were similar to those of another population of PD patients with motor fluctuations.

CONCLUSIONS

During the course of PD, personality dimensions can change in parallel with the development of motor fluctuations, either due to the evolution of the disease and/or dopaminergic treatments.

The functional networks of a novel environment: Neural activity mapping in awake unrestrained rats using positron emission tomography

INTRODUCTION

Novel environment stimulation is thought to have an important role in cognitive development and has been shown to encourage exploratory behavior in rats. However, psychopathology or perceived danger or stress can impede this exploratory drive. The balance between brain circuits controlling the exploratory drive elicited by a novel environment, and the avoidance response to stressors, is not well understood.

METHODS

Using positron emission tomography (PET) and the glucose analog [¹⁸ F]fluorodeoxyglucose (18F-FDG), we assessed awake brain glucose metabolism (BGluM) in rats while in a novel environment (cage of an unfamiliar male rat) and non-novel environment (the animal's home cage).

RESULTS

Exposure to the novel environment increased BGluM in regions associated with vision (visual cortex), motor function and motivated behavior (striatum and motor cortex), and anxiety (stria terminalis), and decreased BGluM in regions associated with auditory processing (auditory cortex, insular cortex, inferior colliculus), locomotor activity (globus pallidus, striatum, motor cortex, ventral thalamic nucleus), spatial navigation (retrosplenial cortex), and working memory (hippocampus, cingulate cortex, prelimbic cortex, orbitofrontal cortex).

CONCLUSION

These results suggest that the novel cage is a stressful environment that inhibits activity in brain regions associated with exploratory behavior. Patterns of inhibition in the novel cage also support the proposed rat default mode network, indicating that animals are more cognitively engaged in this environment. Additionally, these data support the unique capability of combining FDG-PET with psychopharmacology experiments to examine novelty seeking and brain activation in the context of decision making, risk taking, and cognitive function more generally, along with response to environmental or stress challenges.

Cognitive Function, Emotional and Behavioral Problems, and Temperament of Premature Children

Objectives:

We aimed to compare preterm, neurodevelopmentally disordered and healthy full-term children.

Methods:

We enrolled 47 children who were born preterm, 40 neurodevelopmentally disordered children, and 80 healthy children as control participants, in order to assess the cognitive functioning and the risk of behavioral problems at the age of 5. Children were assessed using the Korean Wechsler Preschool and Primary Scale of Intelligence-4th edition (K-WPPSI-IV), the Child Behavior Checklist (CBCL), and the Temperament and Character Inventory (TCI).

Results:

The mean K-WPPSI-IV score of the preterm group was 87.19±17.36, which was significantly higher than that of the neurodevelopmental disorder group (69.98±28.63; p<0.001) but lower than that of the control group (107.74±14.21; p<0.001). The cumulative CBCL scores of the preterm children were not significantly different from those of the control group. Additionally, the TCI scores for reward dependence of the preterm children were higher than those of the control group.

Conclusion:

The cognitive performance of preterm infants was lower than that of healthy full-term infants at the age of 5, and there was an association between slower growth and decreased cognitive ability.

Genetic association of human Corticotropin-Releasing Hormone Receptor 1 (CRHR1) with Internet gaming addiction in Korean male adolescents

BACKGROUND

The number of people with Internet gaming addiction (IGA) is increasing around the world. IGA is known to be associated with personal characteristics, psychosocial factors, and physiological factors. However, few studies have examined the genetic factors related to IGA. This study aimed to investigate the association between IGA and stress-related genetic variants.

METHODS

This cross-sectional study was conducted with 230 male high school students in a South Korean city. We selected five stress-related candidate genes: DAT1, DRD4, NET8, CHRNA4, and CRHR1. The DAT1 and DRD4 genes were genotyped by polymerase chain reaction, and the NET8, CHRNA4, and CRHR1 genes were genotyped by pyrosequencing analysis. We performed a Chi-square test to examine the relationship of these five candidate genes to IGA.

RESULTS

Having the AA genotype and the A allele of the CRHR1 gene (rs28364027) was associated with higher odds of belonging to the IGA participant group (p = .016 and p = .021, respectively) than to the non-IGA group. By contrast, the DAT1, DRD4, NET8, and CHRNA4 gene polymorphisms showed no significant difference between the IGA group and control group.

CONCLUSIONS

These results indicate that polymorphism of the CRHR1 gene may play an important role in IGA susceptibility in the Korean adolescent male population. These findings provide a justification and foundation for further investigation of genetic factors related to IGA.

Neurophysiological Measures and Alcohol Use Disorder (AUD): Hypothesizing Links between Clinical Severity Index and Molecular Neurobiological Patterns

Background

In 1987, Cloninger proposed a clinical description and classification of different personality traits genetically defined and independent from each other. Moreover, he elaborated a specific test the TCI to investigate these traits/states. The study of craving in Alcohol Use Disorder (AUD) assumed a greater significance, since ever more data seems to suggest a direct correlation between high levels of craving and a higher risk of relapse in alcoholics. Thus, our study aim is to explore the possible correlations among TCI linked molecular neurobiological pattern (s), craving and alcohol addiction severity measures in a sample of Italian alcoholics.

Materials and Methods

191 alcoholics were recruited in a Day Hospital (DH) setting at the Alcohol Addiction Program Latium Region Referral Center, Sapienza University of Rome. After 7 days detoxification treatment a psychodiagnostic protocol was administered, including TCI, VAS-C, ASI and SADQ. All patients signed an Institutional Review Board (IRB) approved informed consent.

Results

Principally, we detected a significant positive correlation between HA-scale scores and the VAS scale: increasing in HA-scale corresponds to an increase in craving perception for both intensity (r=0.310; p ≤ 0.001) and frequency (r=0.246; p ≤ 0.001). Moreover, perception of dependence severity, measured with SADQ was also found to be significantly associated positively to both HA-scale (r=0.246; p ≤ 0.001) and NS-scale (r=0.224; p ≤ 0.01). While, for character scales, Persistence (r=−0.195; p=.008) and Self-directedness (r=−0.294; p ≤ 0.001) was negatively associated with ASI linked to alcohol problems. Self-directedness was also negatively correlated with ASI linked to family and social problems (r=−0.349; p ≤ 0.001), employment and support problems (r=−0.220; p=0.003) and psychiatric problems (r=−0.358; p ≤ 0.001). Cooperativeness was a negative correlate with Legal Problems (r=−0.173; p=0.019). and Self-Transcendence was positive correlated with Medical Problems (r=0.276; p ≤ 0.001)

Conclusions

In view of recent addiction neurobiological theories, such as the “Reward Deficiency Syndrome (RDS)” and the Koob model, our data could suggest that our cohort of patients could possibly be in a particular stage of the course of their addiction history. Thus, if our hypothesis will be confirmed, the TCI-based assessment of alcoholics would allow an optimization of the treatment. Clinicians understanding these newer concepts will be able to translate this information to their patients and potentially enhance clinical outcome (s), because it could suggest a functional hypothesis of neurotransmitter circuits that helps to frame the patient in his/her history of addiction.

Analysis of Association between Norepinephrine Transporter Gene Polymorphisms and Personality Traits of NEO-FFI in a Japanese Population

OBJECTIVE

Norepinephrine is an important chemical messenger that is involved in mood and stress in humans, and is reabsorbed by the norepinephrine transporter (NET). According to Cloninger's theory, the noradrenergic system mediates the personality trait of reward dependence. Thus far, although association studies on NET gene polymorphisms and Cloninger's personality traits have been reported, they yielded inconsistent results. Therefore, in the present study we investigated whether or not the 1287G/A, -182T/C and -3081A/T polymorphisms of the NET gene (SLC6A2) are associated with reward dependence-related traits, as assessed by the five-factor model.

METHODS

After written informed consent was obtained from participants, the three NET gene polymorphisms were analyzed by polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP), and personality was assessed by the Neuroticism Extraversion Openness-Five Factor Inventory (NEO-FFI) in 270 Japanese university students.

RESULTS

A significant relation was found between the -3081A/T functional promoter polymorphism and NEO-FFI scores: those with the T allele exhibited a lower extraversion (E) score than those without the T allele (Mann-Whitney U-test: z=-3.861, p<0.001). However, there was no correlation between the other NET gene polymorphisms and E score, and no association with other dimensions and these three polymorphisms.

CONCLUSION

We conclude that the -3081A/T functional polymorphism in the NET gene may affect the extraversion of reward dependence-related traits, as measured by NEO-FFI. However, we used only the shortened version of NEO-PI-R in this study. Further investigations are necessary using the full version of self-rating personality questionnaires.

Temperament and character personality profile and illness-related stress in central serous chorioretinopathy

Psychological stress is a risk factor as well as a consequence of central serous chorioretinopathy (CSC). Impulsiveness, overachievement, emotional instability, and hard-driving competitiveness have been discussed as personality features in CSC patients. We investigated 57 consecutive CSC patients and 57 age- and gender-matched controls by means of the Symptom Checklist 90-R and the Temperament and Character Inventory. Somatic risk factors, illness characteristics, subjective assessment of severity of illness, and illness-related stress in different areas of life (work, private life) were evaluated. CSC patients showed significantly higher emotional distress as measured by the Global Severity Index. The CSC personality was characterized by lower scoring on the character dimension cooperativeness and the temperament dimension reward dependence. Cooperativeness as well as subjective assessment of severity of CSC has been recognized as significant predictors of illness-related work stress accounting for 30% of variance. Implicating competitiveness, hostility and emotional detachment, lower level of cooperativeness, and reward dependence support the existence of specific aspects of type A behaviour in CSC patients. Low perceived social support and loss of control may explain the significant contribution of this personality dimension to illness-related work stress. Treatment of CSC should thus incorporate psychoeducation about factors contributing to illness-related stress.

Increased plasma norepinephrine concentration in psychotic depression

OBJECTIVE

We previously found psychotic depression (PSDEP) to have positively correlating plasma norepinephrine (NE) and vasopressin (AVP) concentrations. Since central noradrenergic activity and plasma NE concentration are highly correlated, this suggests an increased noradrenergic activation of the hypothalamus-pituitary-adrenal axis. We hypothesize the increased release of NE in PSDEP to be an associated mechanism.

METHODS

To test this hypothesis we analyzed the relation between plasma NE and PSDEP in a comparison with non-psychotically depressed patients. Potentially confounding variables were, among others, melancholia and two better validated subcategories in the field of melancholia and endogenous depression, three global dimensions of psychopathology - Emotional Dysregulation, Retardation and Anxiety - smoking habit, and different types of psychotropic and particularly antidepressant treatment. The data from nine patients with PSDEP and 69 patients with non-PSDEP were reanalysed.

RESULTS

Analysis of covariance controlling for the effects of tricyclic antidepressant treatment (≥100 mg) and smoking habit showed that PSDEP had an increased concentration of plasma NE. The previously found correlation between plasma NE and AVP was still present after correcting for the effects of confounding variables.

CONCLUSIONS

The results suggest an increased activity of the sympathetic nervous system in PSDEP that may act as a specific mechanism for increased vasopressinergic activation. This supports the view of PSDEP as a distinct subcategory of major depression.

Temperament and character in psychotic depression compared with other subcategories of depression and normal controls

Background. Support has been found for high harm avoidance as general vulnerability trait for depression and decreased self-directedness (SD) as central state-related personality change. Additional personality characteristics could be present in psychotic depression (PD). Increased noradrenergic activation in PD predicts the involvement of reward dependence (RD). Methods. The data during the acute episode and after full remission from the same subjects, that we used before, were reanalyzed. The dependence of the 7 dimensions of the Temperament and Character Inventory version 9 on PD, three other subcategories of depression, and a group of normal controls was tested by MANCOVA. Results. Low RD at both time points, and low Cooperativeness during the acute episode, were found as additional characteristics of PD. Conclusion. The combination of two premorbid temperaments, high HA and low RD, and the development of a state-related reduction of two character functions, SD and CO, may be the precondition for the development of combined depressive and psychotic psychopathology.

Association study between reward dependence temperament and a polymorphism in the phenylethanolamine N-methyltransferase gene in a Japanese female population

Cloninger's theory is that specific dimensions of temperament are associated with single neurotransmitter systems, and it is based on neurophysiologic and genetic approaches to the human traits. It suggests that overexpression of temperament could cause psychiatric illness. Based on this theory, we examined the correlation between reward dependence (RD) trait, measured with the Temperament and Character Inventory, and 5 polymorphisms in genes of norepinephrine pathways, ADRB1, COMT, PNMT, SLC18A1, and SLC6A2, in 85 Japanese female nursing students. We found that rs3764351 in PNMT was significantly associated with RD on Fisher's exact test (P = .029, P(corr) = .236). When haplotype analysis was performed for rs3764351 and rs876493 polymorphisms in the 5' flanking region of PNMT, 3 haplotypes were identified. Rs3764351 itself appeared to be correlated with RD in the present study of a specific population, although we could not demonstrate an association between RD and any of the haplotypes. Our findings have implications for the understanding of temperament using neurophysiologic approaches.

Associations between Cloninger's temperament dimensions and acute tobacco withdrawal

This study examined associations between three temperament dimensions measured by the Temperament and Character Inventory-125 [Cloninger, C.R. (1992). The Temperament and Character Inventory-125 (TCI-125; Version 1.)] and tobacco abstinence effects. Smokers (N=203, >/= 15 cigarettes/day) attended two laboratory sessions, one following 12 h of abstinence and the other following ad libitum smoking (order counterbalanced). Participants completed measures of withdrawal symptoms, cigarette urges, and affect. Smokers high in Novelty Seeking reported greater abstinence-induced increases in several nicotine withdrawal symptoms, negative affect, and cigarette craving. Smokers high in Harm Avoidance reported greater abstinence-induced increases in negative affect and urges to smoke to relieve distress. Reward Dependence was not associated with abstinence effects. Novelty Seeking and Harm Avoidance showed independent predictive associations with negative affect and urges, and their associations with abstinence effects persisted when controlling for FTND scores. Smokers with different temperaments display different patterns of acute tobacco withdrawal, and may benefit from treatments matched to their particular abstinence profile.

Association between cytochrome P450 (CYP) 2C19 polymorphisms and harm avoidance in Japanese

Polymorphic enzyme cytochrome P450 (CYP) 2C19 is expressed not only in the liver but also in the brain and mediates the biotransformation of 5-hydroxytriptamine (5-HT). We investigated possible association between genetic polymorphism of CYP2C19 and individual personality traits, possibly influenced by neurotransmitters. Mentally and physically healthy Japanese subjects were enrolled in this study (n = 352). Temperament and Character Inventory (TCI) and CYP2C19 genotyping were performed in all subjects. We detected CYP2C19*2 and *3 (http://www.imm.ki.se/CYPalleles/) using Amplichip CYP450 DNA tip. The number of genotypes classified as homozygous extensive metabolizer (EM), heterozygous EM, and poor metabolizer were 113, 181, and 58, respectively. Significant difference was found in TCI score in harm avoidance (HA; F = 3.138, P < 0.05). Post hoc analysis showed that TCI score in harm avoidance in homozygous EM was significantly lower than that in heterozygous EM (P < 0.05) or PM (P < 0.05). In sub-item analyses, HA3 (shyness with strangers, P < 0.01) and HA1 (anticipatory worry, P < 0.05) of TCI scores were significantly different among CYP2C19 genotypes. Meanwhile, there were no differences in TCI scores of novelty seeking (NS; F = 0.350, n.s.), reward dependence (RD; F = 1.080, n.s.), or persistence (P; F = 0.786, n.s.) among CYP2C19 genotypes. This study demonstrated that a significant association between CYP2C19 activity and HA is present in Japanese.

Can personality traits and gender predict the response to morphine? An experimental cold pain study

The aim of the present study was to examine the possible role of personality traits, in accordance with Cloninger's theory, and gender, in the variability of responsiveness to opioids. Specifically, it was intended to test whether or not the three personality dimensions - harm avoidance (HA), reward dependence (RD) and novelty seeking (NS) - as suggested by Cloninger, can predict inter-personal differences in responsiveness to morphine after exposure to experimental cold pain. Thirty-four healthy volunteers (15 females, 19 males) were given the cold pressor test (CPT). Pain threshold, tolerance, and magnitude (VAS) were measured before and after (six measures, 30 min apart) the administration of either 0.5 mg/kg oral morphine sulphate (n=21) or 0.33 mg/kg oral active placebo (diphenhydramine) (n=13) in a randomized, double blind design. Assessment of the three personality traits, according to Cloninger's Tridimensional Personality Questionnaire, was performed before the CPT. A high HA score (but not RD, NS, or baseline values of the three pain parameters) predicted a significantly larger pain relief following the administration of morphine sulphate (but not of the placebo). Women exhibited a larger response in response to both treatments, as indicated by a significantly increased threshold and tolerance following morphine sulphate as well as significantly increased tolerance and decreased magnitude following placebo administration. The present study confirms the existence of individual differences in response to analgesic treatment. It suggests that high HA personality trait is associated with better responsiveness to morphine treatment, and that females respond better than men to both morphine and placebo.

Personality traits as risk factors of depression and anxiety among Japanese students

The aim of this study is to examine the effects of personality (temperament and character) on specific depression and specific anxiety. A total of 541 Japanese undergraduates were investigated by using the Temperament and Character Inventory (TCI) and the Hospital Anxiety and Depression (HAD) scale. Hierarchical multiple regression analyses demonstrated that specific depression was predicted by lower Reward-Dependence, Persistence, Self-Directedness, Cooperativeness, and Self-Transcendence; specific anxiety was predicted by higher Novelty-Seeking, Harm-Avoidance, Persistence, and Self-Transcendence, and lower Self-Directedness. Immaturity of Self-Directedness is a risk factor for negative affectivity. Immaturity of all character dimensions is a risk factor for specific depression. The relationship between Harm-Avoidance and depression in previous studies may be linked partly to somatic symptoms that were deliberately eliminated in the HAD scale.

Reward dependence is related to norepinephrine transporter T-182C gene polymorphism in a Korean population

It is well established that approximately 50% of the variance in personality traits is genetic. The goal of this study was to investigate a relationship between personality traits and the T-182C polymorphism in the norepinephrine transporter gene. The participants included 115 healthy adults with no history of psychiatric disorders and other physical illness during the past 6 months. All participants were tested with the Temperament and Character Inventory and genotyped norepinephrine transporter gene polymorphism. Differences on the Temperament and Character Inventory dimensions among three groups were examined with one-way analysis of variance. Our study suggests that the norepinephrine transporter T-182C gene polymorphism is associated with reward dependence in Koreans, but the small number of study participants and their sex and age heterogeneity limits generalization of our results. Further studies are necessary with a larger number of homogeneous participants to confirm whether the norepinephrine transporter gene is related to personality traits.

Psychometric Properties of the Temperament and Character Inventory–Revised (TCI–R) in a Belgian Sample

The Temperament and Character Inventory (TCI; Cloninger, Przybeck, Svrakic, & Wetzel, 1994) is a self-questionnaire developed to assess the 7 dimensions of personality described by Cloninger et al. (1994) with a total of 29 subscales. In 1999, a revised version was proposed by Cloninger (TCI-R). In this study, we present psychometric properties of the TCI-R from 958 French-speaking participants of Belgium. Women exhibited higher scores for harm avoidance, reward dependence, and cooperativeness dimensions. The proposed factorial structure of 4 temperament dimensions and 3 character dimensions was confirmed. The TCI-R inventory had good test-retest reliabilities as well as good alpha coefficients. The addition of 3 new subscales to the original scale for Persistence has produced a very reliable dimension in the TCI-R.

Sex differences in cortisol response to reboxetine

This study examined the cortisol response to reboxetine in a sample of healthy men and women. Forty healthy volunteers were randomly allocated to one of two treatment groups: placebo or 4 mg reboxetine under double-blind conditions. Saliva cortisol was measured pre, 1 and 1.5 h post-treatment. Mood and side-effects were also measured. A single oral dose of 4 mg reboxetine did not affect positive or negative mood but did produce some side-effects. It was also sufficient to increase cortisol release 1.5 h post-treatment compared to placebo. In addition, reboxetine lead to a significantly increased cortisol release in male compared to female volunteers. The results suggest that healthy male volunteers are more responsive to challenge with a noradrenergic compound than females.

The tridimensional personality theory and pain: harm avoidance and reward dependence traits correlate with pain perception in healthy volunteers

The aim of the present study was to examine the possible role of personality traits in determining the variability of pain perception among individuals. More specifically, it was intended to test whether or not the three personality dimensions suggested by Cloninger in 1987 - mainly harm avoidance (HA), but also reward dependence (RD), and novelty seeking (NS), can predict interpersonal differences in responsiveness to experimental pain. Seventy healthy volunteers participated in the study. Their personality traits were evaluated through Cloninger's tridimensional personality questionnaire (TPQ). Pain threshold (latency to pain onset), pain magnitude (VAS), and pain tolerance (time to withdrawal) were measured by using the cold pressor test. Bonferroni-adjusted correlations were found between HA and the pain parameters as follows: a negative correlation between HA and threshold (rho=-0.297, P(adj)=0.039); no significant correlation between HA and tolerance (rho=-0.219, P(adj)=0.207); and a trend for a positive correlation between HA and VAS (rho=0.266, P(adj)=0.081). Possible correlations between pain perception and the various possible combinations of high and low scoring for each of the three traits were also investigated. Correlations were found only for the combinations of high/low HA and high/low RD. The low HA/low RD combination demonstrated the lowest responsiveness to pain (VAS 65.2+/-21.4; tolerance 107.6+/-71.8 s), whereas the high HA/low RD combination was correlated with the highest responsiveness (VAS 83.3+/-10.8; tolerance 30.8+/-28.4 s). The results indicate that HA personality trait correlates best with pain responsiveness. As such, a high HA are likely to predict a heightened pain response. RD may modify this pattern. The possible relevant behavioral and neuro-chemical mechanisms are discussed.

Norepinephrine transporter and alpha(2c) adrenoceptor allelic variants and personality factors

It has been suggested that reward dependence, as measured by the Tridimensional Personality Questionnaire (TPQ), is related to central noradrenergic activity, a proposition supported by two studies of urinary norepinephrine metabolite. In the current investigation, 190 normal young Han Chinese were examined, with genetic polymorphisms determined for the norepinephrine transporter (1287G/A) and the alpha(2c)-adrenoceptor (Del322-325) to test the association with TPQ personality traits. No significant association was demonstrated for these two polymorphisms and any of the TPQ personality-factor scores, including reward dependence and its subscales. Our negative findings suggest that the investigated polymorphisms of the norepinephrine transporter and the alpha(2c) adrenoceptor do not play a major role in the reward-dependence personality trait as assessed by TPQ.

Relationship of temperament and behaviour measures to the prolactin response to fenfluramine in depressed men

Low central nervous systems (CNS) serotonin has been linked to aggression, impulsivity and disinhibition in both animal and human studies. Low cerebrospinal fluid (CSF) 5-hydroxindoleacetic acid (5HIAA) has been reported in violent criminals, arsonists and violent suicide attempters. Reduced prolactin response to fenfluramine has been found in aggressive patients and criminal offenders. Cloninger's dimension of harm avoidance is hypothesised to be related to CNS serotonin levels, but studies have reported contradictory results. Forty-eight men with major depression received a fenfluramine challenge as well as a number of measures of temperament and behaviour: the Tridimensional Personality Questionnaire (TPQ); the Eysenck Personality Questionnaire (EPQ); the Barratt Impulsivity Scale (BIS); the Hopkins Symptom Checklist (SCL-90); and clinician-rated personality disorder symptoms. The prolactin response to fenfluramine was not related to EPQ or TPQ measures except the TPQ dimension of reward dependence and the EPQ Lie scale. The prolactin response to fenfluramine was not related to BIS measures or to SCL-90 measures except the SCL-90 somatization scale. The prolactin response to fenfluramine was not related to personality disorder diagnoses or to a measure of repeated self-harm. Thus, in a sample of moderately depressed male outpatients, there was very little relationship between personality, behavioural measures and the prolactin response to fenfluramine. We suggest that alterations in serotonin functioning, when measured using the prolactin response to fenfluramine, may be more commonly linked to behavioural abnormalities in personality-disordered or criminal samples.

Neurotransmitters, temperament and social functioning

Dimensional models can be usefully employed to describe both normal and disordered personality. Studies in molecular genetics, receptor binding, peripheral monoamines and pharmacological challenges have investigated the neurochemical basis of personality. Substantial evidence now exists to support a psychobiological model but the specificity of Cloninger's theory has not always been confirmed. Clinical studies have shown both temperament and character dimensions to improve with pharmacological treatment especially in treatment responders. Some personality changes are found to be independent of clinical effects and even to occur in normal subjects. Models of personality can help in predicting treatment outcome but individual dimensions may not be useful. It is hypothesised that social adaptation is related to the character dimensions and different sources of evidence link these to serotonergic actions. However, recent clinical studies have shown a specific effect of noradrenaline on self-perception and social motivation. Drugs with specific actions on different neurotransmitters may exert a distinctive pattern of effects on personality and social behaviour.

Neuroendocrine correlates of temperament traits in abstinent opiate addicts

PURPOSE

Studies investigating temperament traits of drug abusers and their biological correlates have disclosed high rates of novelty seeking (NS) in opiate addicts, possibly based on dysfunctions of the dopaminergic (DA) system. The aims of the present study were to see whether or not the monoamine functions were impaired in detoxified addicts and whether or not these alterations were correlated with temperament traits, given the possibility that impairment of the biological and temperament parameters might be responsible for the development of addiction.

METHODS

We have investigated the DA, serotonergic (5-HT), and noradrenergic (NE) functions in 22 abstinent heroin addicts and 22 healthy controls by challenging the monoamine systems with the DA agonist bromocriptine (brom), the 5-HT agonist D-fenfluramine (D-fen), and the NE agonist clonidine (clon), respectively. We examined the temperament traits by measuring NS, harm avoidance (HA), and reward dependence (RD) using the "Three-Dimensional Personality Questionnaire" (TPQ).

RESULTS

Addicts showed higher than normal NS scores at TPQ blunted 5-HT function, and normal DA and NE activities, in response to the neuroendocrine challenges. NS correlated negatively with the DA function in both addicts and controls, and negatively with the 5-HT function only in addicts. HA correlated positively with 5-HT function in controls but not in addicts.

IMPLICATIONS

The impairment in 5-HT function observed in heroin addicts and the changes in the biological correlates of temperamental traits could increase the proneness to addiction and possible comorbid psychiatric disorders.

Aminergic tone correlates of migraine and tension-type headache: a study using the tridimensional personality questionnaire

BACKGROUND

Aminergic neurotransmitter activity has been studied in many neuropsychiatric diseases by means of a self-administered questionnaire proposed by Cloninger. Given that central aminergic modulation plays a major role in the pathophysiology of primary headaches, we investigated the personality dimensions related to aminergic neurotransmitter activity in patients with migraine and tension-type headache.

METHODS

From a consecutive series of 230 patients, we selected those presenting with migraine and tension-type headache according to the International Headache Society criteria. All patients were assessed by means of the Cloninger 100-item self-report Tridimensional Personality Questionnaire and a depression scale. The four dimensions of personality are novelty seeking (dopaminergic), harm avoidance (serotonergic), reward dependence (noradrenergic), and persistence (glutaminergic).

RESULTS

One hundred twenty-one patients presenting with migraine and 42 with tension-type headache were recruited. The results indicate significantly higher harm avoidance scores (P<.001) in both patients with migraine and those with tension-type headache than in controls. Furthermore, patients with migraine had a significantly low score in the novelty seeking dimension (P<.001). When we compared only the two groups of patients with headache, we found that the persistence dimension alone was significantly higher in patients with migraine than in those with tension-type headache (P<.05). No differences were observed either in the overall scores of the other personality dimensions or in the depression scale scores.

CONCLUSIONS

The Tridimensional Personality Questionnaire results support a role of the serotonergic system in both migraine and tension-type headache pathophysiology. A dysfunction of dopaminergic and glutaminergic tone seems to be a specific feature of migraine.

Neuroendocrine correlates of temperamental traits in humans

Studies investigating temperament traits in humans and their biological correlates have found high levels of novelty seeking (NS) linked with dopaminergic system changes, and particularly a deficit of dopamine transporter. Harm avoidance and reward dependence, on the other hand, appeared to be associated, respectively with serotonin and noradrenaline changes. In the present study, we have investigated the dopaminergic (DA), serotonergic (5-HT), and noradrenergic (NE) functions in healthy volunteers by challenging the monoamine systems with the DA agonist bromocriptine, the 5-HT agonist D-fenfluramine, and the NE agonist clonidine, respectively. Parallel to this investigation, we examined the temperament traits of our subjects by measuring NS, harm avoidance (HA) and reward dependence (RD) using the 'Three-dimensional Personality Questionnaire' (TPQ). The aims of the study were to see whether or not the monoamine functions were correlated with temperament traits. Bromocriptine challenge induced a significant GH increase and a significant suppression of PRL. D-fenfluramine test significantly increased PRL and cortisol plasma levels and Clonidine test induced a significant rise in GH values. NS scores showed a significant direct correlation with brom-stimulated GH values (r=0.426, P<0.05) and a significant inverse correlation with brom-inhibited PRL values (r=-0.498, P<0.01). HA scores correlated significantly with D-fen-stimulated PRL and CORT AUCs, (PRL: r=0.424, P<0.05; CORT: r=0. 595, P<0.005). RD scores correlated positively with clon-stimulated GH values (r=0.55; F=8.6; P<0.01) and negatively with brom-inhibited-PRL AUCs (r=-0.439, P<0.05). Our data support Cloninger theory concerning the biological correlates of temperamental traits, and evidence the link between the neuroendocrine responses to dynamic challenges and stable temperament features.

Correlation between human personality and neural activity in cerebral cortex

Personality traits are a variance of behavioral patterns among individuals and may reflect a variance of brain activity, but their neurobiological explanation is still a matter of debate. Cloninger proposed three dimensions of personality traits, each of which has strong correlation with activity in a specific central monoaminergic system. Although this theory has been supported by physiological and genetic studies, it is still unclear how these personality parameters are correlated with the activity of the cortical networks which control human behavior. Here we measured the regional cerebral blood flow (rCBF) at rest in 30 normal volunteers who completed the personality inventory of Cloninger. Voxel-by-voxel analysis was employed to identify cortical regions where the rCBF showed significant correlation with any of the three personality parameters. Statistically significant correlation was observed in several paralimbic and neocortical regions and was consistent with the assumed monoaminergic influence on neural activity and the distribution of its projections, in each personality dimension. The results suggest that activity in a variety of cortical regions is associated with human personality traits and lend support to Cloninger's theory concerning central monoaminergic influence on human personality traits.

Sociodemographic predictors of temperament and character

The Unified Biosocial Theory of Personality postulates that human personality is organized around four temperaments - Novelty Seeking, Harm Avoidance, Reward Dependence, and Persistence - and three characters - Self-Directedness, Cooperativeness, and Self-Transcendence. The objective of the present study was to investigate the influence of sociodemographic factors on temperament and character without the confounding influence of mental disorders. Volunteers (n=94) did not meet criteria for any Axis I and Axis II diagnosis, had no first-degree relatives with mental disorders, and were medically healthy. After giving written informed consent, volunteers completed the Temperament and Character Inventory. Analyses were conducted to determine the degree of association of each sociodemographic factor (i.e., age, gender, ethnicity, marital status, educational attainment, and occupational status) to personality dimension, while controlling for possible interactions with other sociodemographic factors. Partial correlation analysis showed a significant association between gender and Reward Dependence, and occupational status was significantly related to Reward Dependence, Cooperativeness, and Self-Transcendence. Stepwise regression analysis indicated that gender and occupational status were significant predictors of Reward Dependence. Occupational status was the only predictor of Cooperativeness and Self-Transcendence. These data suggest that sociodemographic factors should be considered in studies investigating temperaments and characters as defined by the Unified Biosocial Theory of Personality.