Linking an Anxiety-Related Personality Trait to Cardiac Autonomic Regulation in Well-Defined Healthy Adults: Harm Avoidance and Resting Heart Rate Variability

OBJECTIVE: Anxiety trait, anxiety and depression states have all been reported to increase risks for cardiovascular disease (CVD), possibly through altering cardiac autonomic regulation. Our aim was to investigate whether the relationship between harm avoidance (HA, an anxiety-related personality trait) and cardiac autonomic regulation is independent of anxiety and depression states in healthy adults. METHODS: We recruited 535 physically and mentally healthy volunteers. Participants completed the Beck Anxiety Inventory (BAI), Beck Depression Inventory (BDI) and Tri-dimensional Personality Questionnaire. Participants were divided into high or low HA groups as discriminated by the quartile value. Cardiac autonomic function was evaluated by measuring heart rate variability (HRV). We obtained the time and frequency-domain indices of HRV including variance (total HRV), the low-frequency power (LF; 0.05-0.15 Hz), which may reflect baroreflex function, the high-frequency power (HF; 0.15-0.40 Hz), which reflects cardiac parasympathetic activity, as well as the LF/HF ratio. RESULTS: The BDI and HA scores showed associations with HRV parameters. After adjustment for the BDI scores and other control variables, HA is still associated with reduced variance, LF and HF power. Compared with the participants with low HA, those with high HA displayed significant reductions in variance, LF and HF power and a significant increase in their LF/HF ratio. CONCLUSION: This study highlights the independent role of HA in contributing to decreased autonomic cardiac regulation in healthy adults and provides a potential underlying mechanism for anxiety trait to confer increased risk for CVD.

Relationships between Chronotypes and Temperament and Character Dimensions in Healthy Young Adults

OBJECTIVES: Circadian rhythms have been known to have associations with psychiatric disorders and personality traits. The present study investigated the relationships between circadian typology and temperaments/characters in a non-clinical Korean population. METHODS: Two hundred six healthy Korean college students (male 109, female 97) participated in this study. The subjects completed the Composite Scale of Morningness for circadian typology and 140-item Temperament and Character Inventory-Revised-Short version (TCI-RS). RESULTS: Multivariate analyses of covariance showed a significant association between chronotypes and temperamental dimensions of the TCI-RS. Morning types were significantly associated with lower harm avoidance and higher persistence and self-directedness dimensions, compared to evening types and intermediate types. No interaction effects between sex and chronotypes were shown for temperamental dimensions. CONCLUSIONS: The present findings suggest that high persistence and self-directedness characters are related to morning types and high harm avoidance temperament is more related to evening types.

Evaluation of Temperament and Character Features as Risk Factors for Depressive Symptoms in Patients with Restless Legs Syndrome

BACKGROUND AND PURPOSE: Restless legs syndrome (RLS) is a common sleep-related movement disorder that is frequently associated with psychological disturbances. Personality traits are of considerable importance with respect to coping with chronic illness and disease vulnerability. This study assessed the temperament and character traits of RLS patients using an approach that involves the psychobiological model of personality. METHODS: The personality features of 65 newly diagnosed and untreated RLS patients with no neurological or psychiatric diseases and 109 healthy controls were determined using the Temperament and Character Inventory and compared using covariance analyses. The International RLS Study Group Severity Scale was used to assess the severity of the RLS symptoms, and the Beck Depression Inventory was used to assess the presence and severity of depressive symptoms. RESULTS: RLS patients scored significantly higher than healthy controls on the temperament dimension of harm avoidance (HA, p=0.02) and significantly lower on self-directedness (SD, p=0.001). No significant difference was observed in terms of the temperament dimension of novelty seeking (p=0.435). HA scores were significantly correlated with the BDI score but not with the RLS severity or duration. CONCLUSIONS: High HA and low SD scores are the main characterizing personality features of RLS patients. These personality dimensions may be among the factors predisposing patients to development of the depressive symptoms that are frequently associated with RLS.

Temperament Affects Sympathetic Nervous Function in a Normal Population

OBJECTIVE: Although specific temperaments have been known to be related to autonomic nervous function in some psychiatric disorders, there are few studies that have examined the relationship between temperaments and autonomic nervous function in a normal population. In this study, we examined the effect of temperament on the sympathetic nervous function in a normal population. METHODS: Sixty eight healthy subjects participated in the present study. Temperament was assessed using the Korean version of the Cloninger Temperament and Character Inventory (TCI). Autonomic nervous function was determined by measuring skin temperature in a resting state, which was recorded for 5 minutes from the palmar surface of the left 5th digit using a thermistor secured with a Velcro(R) band. Pearson's correlation analysis and multiple linear regression were used to examine the relationship between temperament and skin temperature. RESULTS: A higher harm avoidance score was correlated with a lower skin temperature (i.e. an increased sympathetic tone; r=-0.343, p=0.004) whereas a higher persistence score was correlated with a higher skin temperature (r=0.433, p=0.001). Hierarchical linear regression analysis revealed that harm avoidance was able to predict the variance of skin temperature independently, with a variance of 7.1% after controlling for sex, blood pressure and state anxiety and persistence was the factor predicting the variance of skin temperature with a variance of 5.0%. CONCLUSION: These results suggest that high harm avoidance is related to an increased sympathetic nervous function whereas high persistence is related to decreased sympathetic nervous function in a normal population.

The Relationship between Harm Avoidance Temperament and Right Frontal and Left Parietal Lobes in Young Adults: A Cortical Thickness Analysis

OBJECTIVES: Increasing evidence suggests the presence of neurobiological bases for temperamental characteristics in humans. Brain correlates of harm avoidance(HA) have been most extensively studied using functional and structural brain imaging methods due to its potential link with anxiety and depressive disorders. To date, however, we are not aware of any reports that have examined the potential relationship between HA levels and regional cortical thickness. The aim of the current study is to examine the cortical thickness which is associated with HA temperament in healthy young subjects. METHODS: Twenty-eight young, healthy individuals(13 men and 15 women, mean age, 29.4 +/- 6.3 years) were screened for eligibility and administered the Korean version of the Cloninger's Temperament and Character Inventory and underwent high-resolution structural magnetic resonance imaging scanning. RESULTS: HA was associated with cortical thickness in the right superior frontal cortex and in the left parietal cortex, adjusted for age and sex and corrected for multiple comparisons using the permutation testing method. CONCLUSION: Individual temperamental differences in HA are associated with structural variations in specific areas of the brain. The fact that these brain regions are involved in top-down modulations of subcortical fear reactions adds functional significance to current findings.

No Association between 5-HTTLPR and Harm Avoidance in Korean College Students

There have been numerous studies on the association between 5-HTTLPR (polymorphisms in the promoter region of the serotonin transporter gene) and anxietyrelated personality traits, with conflicting results. In this study, we administered Korean version of the Temperament and Character Inventory (K-TCI) to a sample of 158 Korean college students and genotyped for the 5-HTTLPR in order to compare the TCI dimensional scores including harm avoidance according to the 5-HTTLPR genotype and sex. We could not find the association between 5-HTTLPR and harm avoidance and other TCI measures. Considering known allele frequencies differences of 5-HTTLPR among different ethnic groups, further cross-cultural studies with a larger sample would be needed.

The Properties of Temperament, Character and Stress Response in Patients with Irritable Bowel Syndrome / 신경정신의학

OBJECTIVES: The purpose of this study was to assess the specific properties of temperament, character and stress response in patients with irritable bowel syndrome compared to those with peptic ulcer disease and healthy controls. METHODS: We studied nineteen subjects with irritable bowel syndrome, twenty-six subjects with peptic ulcer disease and thirty-three healthy control subjects. All subjects completed Temperament and Character Inventory (TCI), Stress Response Inventory (SRI) and questionnaire of demographic characteristics and several variables. RESULTS: From the results of the TCI's, the scores of harm avoidance (HA1, HA2, HA3, HA4, HA total) were significantly higher in the irritable bowel syndrome group than those of the peptic ulcer disease group or the healthy control group. In contrast, the scores of self directedness (SD3) were lower in the irritable bowel syndrome group than the healthy control group. From the results of the SRI's, somatization, anger, fatigue and frustration were significantly higher in the irritable bowel syndrome group. No significant difference was found in TCI and SRI results between the peptic ulcer disease group and the healthy control group. CONCLUSION: The results of this study suggest that patients with irritable bowel syndrome show specific properties of temperament, character and stress response compared with either peptic ulcer disease patients or healthy controls.

Polymorphisms in 5-HT1Dbeta Receptor Gene and Personality Traits in a Korean Population / 신경정신의학

OBJECTIVES: Recently, there has been a growing enthusiasm in biological approach to personality; the identification of genes responsible for particular personality traits. The aim of this study was to investigate the association between the 5-HT1Dbeta G861C polymorphism and personality traits. METHODS: We recruited 218 normal subjects. The Korean version of the Temperament and Character Inventory (TCI) was used to assess personality traits. From blood samples taken from the subjects, DNA was isolated using standard techniques and the HT1Dbeta G861C polymorphism was genotyped by means of polymerase chain reaction and Homogeneous MassEXTEND method. We classified the subject into the GG, CG, and GG groups according to their genotypes. The differences in the temperament factors of the TCI between homozygote group (GG+CC genotype) and heterozygote group (CG genotype) were tested. RESULTS: The heterozygote group had significantly lower Harm avoidance (HA) scores and higher Self-directedness scores (SD) than the homozygote group. CONCLUSION: In conclusion, we found some associations between the 5-HT1Dbeta G861C polymorphism and the personality dimension HA and SD in a normal population.

Serotonin Transporter Gene Polymorphisms and Harm Avoidance Personality in Chronic Tension Type Headache and Migraine

BACKGROUND: Serotonin transporter protein (5-HTT) is a key modulating protein in synaptic serotonergic neurotransmission. Among serotonin gene-linked polymorphism, the promoter, located in the regulatory region of the 5-HTT gene linked polymorphic region (5-HTTLPR), has two alleles with different transcriptional efficiencies. The harm avoidance (HA) personality dimension, estimated by a self-administered tri-dimensional personality questionnaire (TPQ), has been postulated to be heritable and associated with serotonergic neurotransmitter activity. We therefore investigated 5-HTTLPR and HA in patients with chronic tension type headache and migraine. METHODS: We amplified the 5-HTTLPR by means of polymerase chain reaction and performed genotype polymorphism analyses and investigated the serotonin related personality trait by evaluating the HA dimension in tridimensional personality questionnaire (TPQ) in 107 patients with chronic tension type headache (CTH) and in 115 patients with migraine without aura (MWOA) and in 100 healthy controls. RESULTS: We found an excess frequency of the short allele and a different genotype distribution in patients with CTH. S/S genotype frequency was significantly higher in patients with CTH (76%) than in those with MWOA (61%) and controls (59%; P=0.18). TPQ questionnaires showed significantly higher HA scores in both CTH (21.4 +/- 6.3) and MWOA (21.3 +/- 7.2) compared with controls (16.31 +/- 6.1). CONCLUSIONS: This suggests a serotonergic activity might be involved in development of CTH and MWOA and 5-HTTLPR might be one of the genetically contributing factors, especially in patients with CTH through presence of the S allele.

Genetically Determined Serotonergic Activity Contributes to Development of Analgesics Overuse in Chronic Tension Type Headache

BACKGROUND: Approximately one half of the patients with chronic daily headaches report a regular use of analgesics, making it an important issue for public health matters. However, factors contributing to the dependency and overuse of analgesics for chronic tension type headaches have been little understood. We investigated the role of chronic analgesics exposure in the natural course and clinical phenotype of headaches in patients with chronic tension type headaches. We also evaluated genetically determined innate factor that could exert a profound influence on a development of analgesics overuse using a serotonin transporter protein polymorphism and serotonergically related harm avoidance (HA) personality dimension. METHODS: We analyzed the headache characteristics using a standardized questionnaire from 38 patients with chronic tension type headache with analgesics overuse (CTTH-AO), from 40 patients with chronic tension type headache without analgesics overuse (CTTH-NO) and from 100 healthy controls. We performed the serotonin transporter protein gene linked to the polymorphic region (5-HTTLPR) genotype, polymorphism analyses and investigated the serotonin related personality trait by evaluating the HA dimension in tri-dimensional personality questionnaires (TPQ). RESULTS: We found a significantly higher pain intensity and disability score in patients with CTTH-AO. Most of the patients with CTTH-AO used analgesics compound containing caffeine for pain relief. S/S genotype frequency was significantly higher in patients with CTTH-AO than in those with CTTH-NO and controls. TPQ questionnaires showed significantly higher HA scores in both CTTH-AO and CTTH-NO than in controls. CONCLUSIONS: This suggests a serotonergic activity might be involved in development of analgesics overuse in chronic tension type headaches, and 5-HTTLPR might be one of the genetically contributing factors.

Temperament and Character Inventory and Remission State of Depression / 신경정신의학

OBJECTIVES: There are many studies that assessed the relationship between Cloninger's Temperament and Character Inventory (TCI) on depression, and the relationship between depression and personality trait has been debated for many years. In this study, the relationship between the TCI and remission state of depression in respect to personality trait was examined. METHODS: The subjects were composed of 50 patients who have been diagnosed as major depressive disorder by DSM-IV. Depressed patients' Hamilton Depression Scale (HAM-D) scores were over 18 and those in remission were HAM-D score lower than 8. The 50 depressed subjects and 50 healthy controls were asked to complete the TCI. RESULTS: The depressed patients in remission exhibited higher harm avoidance and lower persistence scores compared to healthy controls. CONCLUSION: This study confirms the trait dependence of the harm avoidance dimension.