Polymorphisms in the serotonin transporter and monoamine oxidase A genes and their relationship to personality traits measured by the Temperament and Character Inventory and NEO Five-Factor Inventory in healthy volunteers

The associations between 5-HTT-linked polymorphic region (5-HTT-LPR), monoamine oxidase A (MAOA)-LPR and the dimensions of temperament evaluated using the Temperament and Character Inventory (TCI) and NEO Five-Factor Inventory (NEO-FFI) were studied. One hundred healthy volunteers (without psychiatric disorders) were recruited to represent a cross-section of the population of Szczecin (Poland) in terms of sex, age and education. No associations between 5-HTT-LPR and the TCI harm avoidance dimension and between 5-HTT-LPR and the NEO-FFI neuroticism dimension were found. Males carrying the 3-VNTR MAOA gene variant (209 bp) had significantly lower values on the NEO-FFI openness dimension (p = 0.039) and obtained higher scores on the subdimension 3 of the TCI reward dependence (RD3), i.e. attachment vs. detachment (p = 0.005). Individuals carrying the 'short' variant of 5-HTT-LPR had lower values on the reward dependence dimension and the RD4 subdimension (dependence vs. independence) than individuals not carrying the 'short' variant (p = 0.039 and p = 0.011, respectively). Females carrying the 'short' variant had lower values on NS1 (exploratory excitability vs. stoic rigidity) and RD4 (dependence vs. independence) than those not carrying the variant (p = 0.042 and 0.043, respectively). The obtained level of significance with respect to the observed associations between 5-HTT-LPR and the reward dependence scales and subscales and between 5-HTT-LPR and the NS1 subscale are too weak for further interpretation. Our results do not confirm the hypothesis that there is a simple correlation between single gene polymorphisms and a personality trait measured by the TCI and NEO-FFI scales.     

Polymorphisms in the dopamine, serotonin, and norepinephrine transporter genes and their relationship to temperamental dimensions measured by the Temperament and Character Inventory in healthy volunteers

There is evidence for an association between polymorphisms of monoamine transporter genes and temperamental personality traits. Recent findings have shown that interaction of allelic variants of the different genes may contribute to the personality factors. We studied the association between temperamental personality dimensions measured with the Temperament and Character Inventory (TCI) and polymorphisms of the dopamine (DAT), norepinephrine (NET) and serotonin (5-HTT) transporter genes in 127 healthy Polish volunteers. There were no significant differences between means of TCI temperamental dimensions (novelty seeking, reward dependence, persistence and harm avoidance) and the transporter genes compared by ANOVA. There were some significant associations between genotypes and TCI subdimensions. Individuals carrying the A9/A9 DAT genotype have lower RD4 scores (dependence vs. independence) than A10/A10 individuals (3.0 +/- 1.4 vs. 3.5 +/- 1.3); p = 0.01. Examining 5-HTT gene promoter polymorphism, heterozygous individuals (l/s) and individuals with 44-bp deletion (s/s) scored significantly lower in the HA1 subdimension (anticipatory worry and pessimism vs. uninhibited optimism; 4.3 +/- 2.3 vs. 5.5 +/- 2.6) in comparison with individuals without deletion (l/l); p = 0.021. The NET transporter gene polymorphism showed no significant association with any of the temperamental TCI subdimensions.     

Personality dimensions measured using the Temperament and Character Inventory (TCI) and NEO-FFI on a Polish sample

The results of two self-administered, paper-and-pencil tests based on biosocial theory of personality have been compared simultaneously: the Temperament and Character Inventory (TCI) and NEO Five Factor Inventory (NEO-FFI). The stability of the personality dimensions was assessed across age, sex and education level samples in a group of 406 Polish adults with major mental diseases excluded by use of PRIME-MD questionnaire. Significant effects of age, sex, and education have been found while comparing personality dimensions in both temperamental (novelty seeking, NS; harm avoidance, HA; reward dependence, RD; persistence, P) and character scales (cooperativeness, C; self-transcendence, ST) in TCI. Among subscales of temperament only NS1, RD4 were stable according to concerning factors. All converted to their age and sex norms NEO-FFI dimensions were stable according to sex. Extraversion scale was changeable depending on age (p = 0.04). Neuroticism dimension was a little higher in lower educated group (p = 0.035).To sum up, it was concluded that sex- and age-specific norms for the dimensions of the Polish version of TCI are necessary considering the established significant differences. Particular personality genetic studies should account for age, sex and also educational differences in their methods of associative studies. CONCLUSIONS: In the exploration of personality dimensions on healthy volunteers the Polish version of NEO-FFI corresponds better than TCI to theory of stability and genetic determinants of human personality. As the study included persons with excluded major mental diseases, the sample is appropriate to provide a control group in the research of psychiatric patients using both TCI and NEO-FFI. SIGNIFICANT OUTCOMES: TCI scores for persons with excluded mental disease are highly changeable depending on age, sex and education. Adjusted to sex and age scores NEO-FFI corresponded better than TCI to stability and genetic determinants of human personality.     

Personality traits in patients with juvenile myoclonic epilepsy

There is evidence of personality disorders in patients with juvenile myoclonic epilepsy (JME). To date, there have been no published quantitative studies on personality traits in JME. The aim of the work described here was to study a group of patients with JME and quantitatively measure personality traits. We evaluated 42 patients (mean age: 26.57 years, SD: 8.38) and 42 controls (mean age: 26.96, SD: 8.48) using a validated personality inventory, the Temperament and Character Inventory (TCI). We applied two scores, one for the Beck Depression Inventory and one for the State-Trait-Anxiety Inventory, as depression and anxiety may impact the performance of these patients on the TCI. We compared both groups on TCI scales using analysis of covariance with Beck Depression Inventory and State-Trait-Anxiety Inventory scores as covariates. Patients with JME obtained significantly higher scores on Novelty Seeking (P=0.001) and Harm Avoidance (P=0.002) and significantly lower scores on Self-Directedness (P=0.001). Patients with JME have a higher expression of impulsive personality traits that demand early recognition to avoid further consequences and facilitate social insertion, consequently avoiding future stigma.     

Association of 5-HT1B receptor gene and antisocial behavior in alcoholism

Summary. The 5-HT1B receptor gene has been postulated to play a modulatory role in alcohol consumption and alcohol dependence, and was considered a candidate gene for alcoholism. More recently, the association of the 5-HT receptor gene polymorphism and antisocial personality traits in alcoholism has been discussed. This possible association was studied using material from our gene bank for alcoholism. The research instruments used to phenotype patients were partly adopted from the US Collaborative Study on the Genetics of Alcoholism (COGA) which include anxiety- and depression-related scales from personality inventories such as the temperament and character inventory (TCI), the NEO-Five-Factor Inventory (NEO-FFI) and the Minnesota Multiphase Personality Inventory (MMPI-2). Based on the examination of 164 alcoholic subjects, an association was found between a lower frequency of the 5-HT 1B 861C allele, antisocial personality traits and conduct disorder in alcohol-dependent subjects. Adult antisocial personality occurred more often in males than females. Possible implications of these findings are discussed.     

Minor genetic variants of the dopamine D4 receptor (DRD4) polymorphism are associated with novelty seeking in healthy Japanese subjects

Although an association between the dopamine receptor D4 (DRD4) gene and personality traits had been previously investigated, results from previous studies were not conclusive. This may be due to the method of grouping used, which categorized the gene population into two groups based on the length of the variable number of tandem repeats (VNTR) in exon 3. In the present study, we categorized 616 healthy Japanese subjects into more than two groups by further subdividing the DRD4 48-bp VNTR polymorphism, and compared Temperament and Character Inventory (TCI) scores among the groups. A significant difference was found between the DRD4 48-bp VNTR polymorphism and novelty seeking (p = 0.016). The novelty-seeking scores in the subjects carrying the 5/5 genotype were significantly higher than in those carrying the 2/2 genotype (p = 0.002) or the 4/4 genotype (p = 0.005). However, when the conventional method of grouping was used (i.e., short alleles vs. long alleles), there were no significant associations between the DRD4 VNTR polymorphism and any TCI scores. Our results suggest that minor 5-repeat allele is associated with high novelty-seeking scores in healthy Japanese subjects.     

Temperament and character in subjects with obsessive-compulsive disorder

Background

The aims of this study were to evaluate the differences between personality traits of patients with obsessive-compulsive disorder (OCD) and normal controls using the Temperament and Character Inventory (TCI) and to examine the relationship of personality traits and the severity of obsessive-compulsive (OC) symptoms. We also aimed to examine the influence a particular personality trait might have on the 5 factor-analyzed symptom dimension scores of OCD.

Method

We recruited 130 patients with OCD and 185 age- and sex-matched normal controls. All subjects completed the TCI. Patients with OCD were assessed with the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS), the Hamilton Depression Rating Scale, and the factor-analyzed symptom dimension scores from the Y-BOCS checklist.

Results

Patients with OCD had higher harm avoidance scores and lower self-directedness (SD), reward dependence (RD), and cooperativeness (C) scores than the controls. Lower SD scores and lower C scores were associated with OC symptom severity measured by the Y-BOCS after adjusting for age and depression severity. Hoarding dimension of OC symptoms was associated with lower SD scores and higher persistence (P) scores after adjusting for age, OC symptom severity, and depression severity.

Conclusions

There were significant differences in TCI subscales between patients with OCD and controls. Particular personality traits may have an influence on the severity and the dimensions of OC symptoms.     

Personality traits and schizophrenia: evidence from a case-control study and meta-analysis

Personality is considered to be an important aspect of schizophrenia, primarily because it may influence patients' symptoms and social functioning. Specific personality traits are related to schizophrenia. The Temperament and Character Inventory (TCI) measures four traits of temperament - novelty seeking (NS), harm avoidance (HA), reward dependence (RD) and persistence (PS) - and three traits of character - self-directedness (SD), cooperativeness (CO) and self-transcendence (ST). We investigated associations between schizophrenia and personality traits using the TCI in a Japanese case-control sample (99 patients and 179 controls). Patients with schizophrenia scored higher on HA and ST and lower on NS, RD, SD and CO compared with controls in our case-control sample. We then performed a meta-analysis of samples from the published literature and our sample (384 patients and 656 controls). We found no evidence of heterogeneity among studies, except for NS in the overall population. Possible associations between personality traits (HA, RD, PS, SD, CO and ST) and schizophrenia were revealed. The effect sizes (Hedges' g) of the temperament traits were 0.98 for HA, -0.43 for RD and -0.23 for PS, and those of the character traits were -0.96 for SD, -0.47 for CO and 0.61 for ST. These findings suggest that patients with schizophrenia have a unique temperament and character profile compared with the general population.     

Effect of serotonergic antidepressant therapy on temperament and character scales in patients with chronic tension-type headache

The purpose of the present study was to assess a group of patients with chronic tension-type headache (CTTH) and control subjects using the personality questionnaire proposed by Cloninger and to determine possible changes in the Temperament and Character Inventory (TCI) patterns of CTTH patients after therapy with serotonergic antidepressants. Forty-five patients with CTTH filled out the TCI and Beck Depression Inventory (BDI) before and after 4-month prophylactic therapy with serotonergic antidepressants. A total of 50 age-, sex- and education level-matched healthy subjects were selected as a control group. During the pretreatment period patients were found to have higher harm avoidance and lower self-directedness scores than healthy comparison subjects. During the post-treatment period, although harm avoidance scores decreased and self-directedness scores increased, harm avoidance scores were still significantly higher and self-directedness scores significantly lower in CTTH patients than in controls. After using BDI score and age as covariates at the post-treatment period, harm avoidance scores were still higher in patients with CTTH while self-directedness scores did not differ between CTTH patients and controls. These findings suggest state and trait dependence of harm avoidance, and strong state dependence of self-directedness scores in CTTH patients. When interpreting data regarding personality measured by the TCI in CTTH patients, the effects of depressive symptomatology should be taken into account.     

Personality traits and violent behavior: A comparison between psychopathic and non-psychopathic male murderers

The relationship between psychopathy and traits of temperament and character in a specific population of criminals, such as murderers, has not been sufficiently investigated. This study assesses the relationship between psychopathy and temperament and character traits in murderers. The sample consisted of 118 men divided into three groups: psychopathic murderers (N=40), non-psychopathic murderers (N=40) and 38 non-psychopathic non-criminals (controls). All individuals were evaluated by Psychopathy Checklist Revised (PCL-R) and The Temperament and Character Inventory (TCI). Psychopathic murderers presented higher scores than the other two groups in PCL-R; both criminal groups presented higher scores than non-psychopathic non-criminals. Psychopathic murderers showed lower scores than non-psychopathic murderers on Harm Avoidance, Reward Dependence, Persistence, Self-Directness and Cooperativeness. There was no difference between murderers groups regarding Novelty Seeking and Self-transcendence. In all TCI personality traits psychopathic and non-psychopathic murderers showed scores lower than controls, except Harm Avoidance for non-psychopathic murderers. In conclusion, most personality traits assessed by TCI were associated with psychopathy, while Novelty Seeking and Self-transcendence were associated with homicidal behavior independently of the psychopathy.     

Interaction between serotonin 5-HT2A receptor gene and dopamine transporter (DAT1) gene polymorphisms influences personality trait of persistence in Austrian Caucasians

We examined 89 normal volunteers using Cloninger's Temperament and Character Inventory (TCI). Genotyping the 102T/C polymorphism of the serotonin 5HT2A receptor gene and the ser9gly polymorphism in exon 1 of the dopamine D3 receptor (DRD3) gene was performed using PCR-RFLP, whereas the dopamine transporter (DAT1) gene variable number of tandem repeats (VNTR) polymorphism was investigated using PCR amplification followed by electrophoresis in an 8% acrylamide gel with a set of size markers. We found a nominally significant association between gender and harm avoidance (P=0.017; women showing higher scores). There was no association of either DAT1, DRD3 or 5HT2A alleles or genotypes with any dimension of the TCI applying Kruskal–Wallis rank-sum tests. Comparing homozygote and heterozygote DAT1 genotypes, we found higher novelty seeking scores in homozygotes (P=0.054). We further found a nominally significant interaction between DAT1 and 5HT2A homo-/heterozygous gene variants (P=0.0071; DAT1 and 5HT2A genotypes P value of 0.05), performing multivariate analysis of variance (MANOVA). Examining the temperamental TCI subscales, this interaction was associated with persistence (genotypes: P=0.004; homo-/heterozygous gene variants: P=0.0004). We conclude that an interaction between DAT1 and 5HT2A genes might influence the temperamental personality trait persistence.     

Cerebellar and lobar blood flow in schizophrenia: a perfusion weighted imaging study

Accumulating evidence indicates that cannabis use may be a risk factor for schizophrenia (SZ), and chronic cannabis users score higher than non-users on measures of schizotypal personality traits. The purpose of the present study was to investigate the relations between normal personality, schizotypy, and cannabis use. Sixty-two chronic cannabis users and 45 cannabis-naïve controls completed a measure of normal personality, the NEO-Five Factor Inventory (NEO-FFI), and two measures of schizotypy, the schizotypal personality questionnaire (SPQ) and perceptual aberration scale (PAS). Substance use was assessed using the SCID I alcohol/drug module and a locally developed drug use questionnaire. On the NEO-FFI, users scored higher than controls on openness, but lower on agreeableness and conscientiousness, and endorsed greater schizotypy on the SPQ and PAS. Higher neuroticism predicted greater schizotypy in both groups, and, higher Extraversion predicted lower negative-syndrome schizotypy among users. Finally, duration of cannabis use was positively correlated with scores on the SPQ and PAS among users, suggesting a relation between overall cannabis use chronicity and schizotypy. These data show that cannabis users differ from non-users on dimensions of normal personality and schizotypy, and provide further evidence that cannabis use is associated with increased levels of psychosis-related personality traits.     

Association of genetic polymorphisms with personality profile in individuals without psychiatric disorders

Objective

Population-based twin studies demonstrate that approximately 40–50% of the variability in personality dimensions results from genetic factors.This study assessed selected polymorphisms in the COMT Val158Met, MAOA 3′VNTR, 5HTTLPR, 102T/C 5-HT2A, DAT 3′VNTR and DRD2 exon 8 genes and evaluated their association with personality profiles, anxiety levels, and depressiveness in healthy subjects.

Methods

This study included 406 unrelated (mean age 38.51 years), mentally and somatically healthy Caucasian subjects of Polish origin. The prevalence of the gene variants mentioned above and their association with personality profiles, anxiety levels, and depressiveness was assessed using the Temperament and Character Inventory, NEO Five-Factor Inventory, Spielberger's State-Trait Anxiety Inventory and Beck's Depression Inventory.

Results

The effects of the 5HTTLPR gene on the s/s genotype and empathy (C2) were lowest in the entire group. The effects of gender, age and the HT2A gene for the T/T genotype and attachment (RD3) were highest in women.The effects of gender, age and the DAT gene on the 9/9 DAT genotype, compassion (C4) and cooperativeness (C) were lowest in women. The effects of gender, age and the COMT gene on the Met/Met genotype and neuroticism (NEU) NEO-FFI were also lowest in women.

Conclusions

Our results suggest considerable influence of individual genes on the formation of personality traits.     

Personality traits of patients with mood and anxiety disorders

Although it is well established that personality traits of patients with mental disorder differ significantly from the traits of other persons, differences in personality characteristics between different mental disorders have not been examined very thoroughly. In this study, we examine personality traits in a large sample of outpatients (N=640) with mood and anxiety disorders in differing patterns of comorbidity, using the five-factor model of personality. Mood and anxiety disorders were assessed using the Composite International Diagnostic Inventory, and personality traits were assessed with the NEO Five-Factor Inventory (NEO-FFI). Most of the mean scores on the NEO-FFI scales of the study population were found to be significantly different from the scale scores of the general population. Few differences between NEO-FFI scores for differing patterns of mood and anxiety disorders were found. However, clear differences were found for subjects with one (mood or anxiety) disorder, subjects with two, and subjects with three or more disorders. Neuroticism and agreeableness differed considerably in subjects with one disorder compared with subjects with two or more disorders. The main conclusion is that personality traits appear to be associated with comorbidity and less so with any specific disorder.     

An interaction between the serotonin transporter promoter region and dopamine transporter polymorphisms contributes to harm avoidance and reward dependence traits in normal healthy subjects

Summary. There is evidence for an association between polymorphisms of serotonin- and dopamine-related genes and temperamental personality traits. Recent findings have shown that interactions between allelic variants of the different genes may contribute to personality traits. We examined the effects of serotonin transporter-linked promoter region (5-HTTLPR) and dopamine transporter (DAT1) gene polymorphisms for associations with the Temperament and Character Inventory (TCI) temperament subscales in 209 Koreans. We found that the variants of 5-HTTLPR interacted with the DAT1 gene polymorphism to influence the HA and RD temperament subscales of TCI. Neither of these two genes affected any subscales of TCI alone. Controlling for the effects of gender and age, we found significant interactions between 5-HTTLPR and DAT1 genes on Harm Avoidance (HA) and Reward Dependence (RD) as measured by the TCI (Hotelling’s Trace = 3.0, P = 0.02). In the presence of the DAT1 10/10 genotype, subjects of group L of 5-HTTLPR had a significantly higher HA score and significantly lower RD score than those of group S (F = 5.04, df = 1, p = 0.03 and F = 8.35, df = 1, p = 0.004, respectively). These findings suggest that the variants of 5-HTTLPR interacted with the DAT1 gene polymorphism to influence the HA and RD temperament subscales of TCI.     

Regional cerebral brain metabolism correlates of neuroticism and extraversion

Factor-analytic approaches to human personality have consistently identified several core personality traits, such as Extraversion/Introversion, Neuroticism, Agreeableness, Consciousness, and Openness. There is an increasing recognition that certain personality traits may render individuals vulnerable to psychiatric disorders, including anxiety disorders and depression. Our purpose in this study was to explore correlates between the personality dimensions neuroticism and extraversion as assessed by the NEO Five-Factor Inventory (NEO-FFI) and resting regional cerebral glucose metabolism (rCMRglu) in healthy control subjects. Based on the anxiety and depression literatures, we predicted correlations with a network of brain structures, including ventral and medial prefrontal cortex (encompassing anterior cingulate cortex and orbitofrontal cortex), insular cortex, anterior temporal pole, ventral striatum, and the amygdala. Twenty healthy women completed an (18F)FDG (18F-fluorodeoxyglucose) positron emission tomography (PET) scan at rest and the NEO-FFI inventory. We investigated correlations between scores on NEO-FFI Neuroticism and Extraversion and rCMRglu using statistical parametric mapping (SPM99). Within a priori search territories, we found significant negative correlations between Neuroticism and rCMRglu in the insular cortex and positive correlations between Extraversion and rCMRglu in the orbitofrontal cortex. No significant correlations were found involving anterior cingulate, amygdala, or ventral striatum. Neuroticism and Extraversion are associated with activity in insular cortex and orbitofrontal cortex, respectively.     

Cloninger's temperament and character dimensions of personality in patients with major depressive disorder

In this present study, we examined the relationship between the Cloninger's dimensional psychobiologic model of personality and depression in an outpatient population with major depressive disorder. Eighty-one depressed outpatients (67 women, 14 men) and 51 healthy controls (35 women, 16 men) filled out the Turkish version of the Temperament and Character Inventory (TCI). Depression severity was evaluated by using the 17-item Hamilton Depression Rating Scale and the 21-item Beck Depression Inventory. Depressed patients exhibited statistically significant higher scores for harm avoidance and lower scores for self-directedness compared to healthy controls. Sentimentality (RD1) and dependence (RD4) subscale scores of reward dependence and spiritual acceptance (ST3) subscale of self-transcendence were significantly higher; attachment (RD3) subscale of reward dependence, responsibility (SD1), purposefulness (SD2), resourcefulness (SD3), and congruent second nature (SD5) subscales of self-directedness were significantly lower in the depressed group. In the depressed patient group, main effects of sex were significant for reward dependence and cooperativeness; the scores of both dimensions were higher for women. The Beck Inventory was positively correlated with harm avoidance and negatively correlated with novelty seeking and self-directedness dimensions (P < .05). The duration of depression (16.33 ± 20.18 months) or the mean onset age of depression (28.68 ± 8.11 years) did not show significant correlations with TCI scales. This study confirms the relationship between harm avoidance and depression and suggests a relationship between self-directedness and depression.     

Personality dimensions measured by the Temperament and Character Inventory (TCI) in subjects with social phobia

The present study investigated personality dimensions by means of the Temperament and Character Inventory (TCI) in subjects with social phobia with or without a co-existing avoidant personality disorder. Thirty-one individuals with social phobia were recruited through advertisement and diagnosed with the Structured Clinical Interview for DSM-IV I and II psychiatric disorders. Comorbid Axis I psychiatric disorders were diagnosed in 29% of the cases. Co-occurring personality disorders were present in 55.8% of the cases, and avoidant personality disorder in 48.4%. The social phobia subjects, as compared to healthy controls of the same age, scored significantly higher in the TCI dimension measuring Harm avoidance but significantly lower in Persistence, Self-directedness, Cooperativeness and Self-transcendence. Presence of avoidant personality disorders in the social phobia subjects was associated with significantly higher Harm avoidance, particularly on the subscale Shyness with strangers. In conclusion, individuals with social phobia were characterized by high comorbidity of avoidant personality disorder and deviations in TCI personality dimensions. Enhanced Harm avoidance was the most prominent personality trait. The observed deviations in TCI dimensions were primarily related to the social phobia itself and not to the presence of concurrent personality disorders.     

Personality traits of women with a history of childhood sexual abuse

This study examined relationships between specific dimensions of childhood sexual abuse and personality traits in adulthood. Study participants were 74 hospitalized female psychiatric patients with a self-reported history of childhood sexual abuse. Characteristics of childhood sexual abuse were obtained from a structured life-events interview. Personality was measured with the NEO-Five-Factor Inventory (NEO-FFI), which yields scores on neuroticism, extraversion, openness to experience, agreeableness, and conscientiousness. We hypothesized that parental abuse, intercourse, and the combination of these two childhood sexual abuse characteristics would be associated with personality traits. Supporting this hypothesis, women who were abused by a parent had lower scores on openness to experience than women who were abused by someone else. Patients whose abuse history included both parental abuse and intercourse had very low extraversion scores. Our findings suggest that there are associations between personality traits and childhood sexual abuse characteristics in psychiatric patients. Specifically, women who experienced intercourse by a parent may be more introverted and less open to experience than women whose sexual abuse history does not include parental incest.     

Serotonin transporter gene polymorphism and personality traits in a Korean population

Recently, there has been growing enthusiasm for exploring biological approaches to personality, especially in the area of genetic research into the identification of those genes responsible for particular personality traits. The aim of this study was to investigate the association between the serotonin transporter-linked promoter region (5-HTTLPR) polymorphism and personality traits. We recruited 211 unrelated, normal subjects. The Korean version of the Temperament and Character Inventory (TCI) was used to assess certain personality traits. From blood samples taken from the subjects, DNA was isolated using standard techniques and the 5-HTTLPR polymorphism was genotyped by means of polymerase chain reaction and electrophoresis. We classified the subject into the s/s, s/l, and l/l groups according to their genotype. The differences in the temperament factors of the TCI between group S (s/s genotype) and group L (s/l + l/l genotype) were assessed, after the inclusion of gender and age as covariates in the analysis of variance. After controlling for gender and age, there were no associations between the harm avoidance, novelty seeking, and reward dependence scores and the genotypes. However, the persistence score of group S was significantly higher than that of group L. Our results suggest that the 5-HTTLPR polymorphism may be associated with the persistence score of the TCI in a normal Korean population.