Temperament, health-related behaviors, and autonomic cardiac regulation: The cardiovascular risk in young Finns study

Temperament and character dimensions differ in chronic post-surgical neuropathic pain and cold pressure pain

OBJECTIVES

Psychobiological temperament and cognitive-evaluative character link to coping with chronic pain. The aim was to study possible independent role of temperament and character dimensions both in chronic and experimental pain in chronic post-surgical pain patients. This is a substudy of a previously published larger cohort of patients with intercostobrachial nerve injury after breast cancer surgery.

METHODS

We recruited 241 women who had been treated for breast cancer 4-9 years before. They had a surgeon-verified intercostobrachial nerve injury with or without chronic post-surgical neuropathic pain (CPSNP). The patients filled in the Temperament and Character Inventory (TCI), Pain Catastrophizing Scale (PCS), Hospital Anxiety and Depression Scale (HADS), and Brief Pain Inventory (BPI), and underwent the cold pressor test (CPT).

RESULTS

201 (83%) patients reported chronic pain and 135 (56%) met the criteria for CPSNP. Patients with CPSNP showed higher levels of Harm Avoidance (HA) temperament than non-CPSNP patients, which was associated with lower cold pain tolerance and greater increase of pain intensity during CPT. HA subscales Fear of Uncertainty and Fatigability contributed to a stronger pain experience. For character dimensions, CPSNP patients reported higher levels of Self-Transcendence (ST) and lower levels of Self-Directedness (SD) and Cooperativeness (CO) than non-CPSNP patients. Cold pain tolerance, intensity, or unpleasantness did not associate with character dimensions.

CONCLUSIONS

Psychobiological temperament, but not character, is independently from other psychological factors associated with primary pain processing in an experimental pain setting. Patients with and without CPSNP showed different profiles on both temperament and character dimensions suggesting a combination of heightened emotional vulnerability and lowered personality adaptability in CPSNP patients. Character dimensions associated with clinical but not experimental pain.

ETHICAL COMMITTEE NUMBER

The study protocol was approved by the Ethics Committee of the Helsinki and Uusimaa Hospital District (reference number: 149/13/03/00/14).

TRIAL REGISTRY NUMBER

The study is registered in ClinicalTrials.gov (NCT02487524).

Cardiorespiratory Response to Moderate Hypercapnia in Female College Students Expressing Behaviorally Inhibited Temperament

Behaviorally inhibited (BI) temperament is marked by heightened behavioral sensitivity to environmental threats. The degree to which threat sensitivity is reflected in cardiorespiratory responses has been relatively unexplored. Female college students were exposed to modest hypercapnia (7.0% CO₂) or ambient air (AA) while engaging in a computerized task with cued reinforcement features. All physiological variables except for blood pressure were processed in 4 min epochs corresponding to pre-exposure, exposure, and post-exposure. Primary respiratory measures were respiratory frequency (f_b), tidal volume (V_T), and minute ventilation (V_E). Electrocardiograms (ECGs) were processed using ARTiiFACT software with resultant heart rate variability (HRV) measures in the frequency domain and time domain. Consistent with the literature, modest hypercapnia increased V_T, F_b, and V_E. No differences in respiratory parameters were detected between BI and non-behaviorally inhibited individuals (NI). For HRV in the time domain, RMSSD and NN50 values increased during CO₂ inhalation which then returned to pre-exposure levels after CO₂ cessation. Hypercapnia increased high frequency (HF) power which then recovered. BI exhibited reduced low frequency (LF) power during the pre-exposure period. For NI, LF power reduced over the subsequent phases ameliorating differences between BI and NI. Hypercapnia improved the task performance of BI. This is the largest study of female reactivity to hypercapnia and associated HRV to date. In general, hypercapnia increased time domain HRV and HF power, suggesting a strong vagal influence. Those expressing BI exhibited similar respiratory and HRV reactivity to NI despite inherently reduced LF power. Although 7% CO₂ represents a mild challenge to the respiratory and cardiovascular systems, it is nonetheless sufficient to explore inherent difference in stress reactivity in those vulnerable to develop anxiety disorders.

Childhood heart problems, adulthood emotional stability, and sex associated with self-report heart conditions in adulthood

The present study investigated biomedical, social, and psychological factors associated with self-reported heart conditions in adulthood in a British cohort. In total, 5697 (50.7% males) participants with data on parental socioeconomic status, childhood cognitive ability, childhood heart problems, educational qualifications, current occupational levels, adulthood personality traits, and the prevalence of self-reported heart conditions in adulthood were included in the study. The prevalence of self-reported heart conditions measured at age 54 years was the outcome variable. Hierarchical logistic regression analysis showed that childhood heart problems identified by physicians (OR = 3.47:1.74-6.92, p < 0.001) and trait emotional stability (OR = 0.83:0.75-0.93, p < 0.001) were the significant and independent predictors of self-reported heart conditions in adulthood. There were also significant sex effects on the prevalence of the outcome variable (OR = 0.53:0.42-0.63, p < 0.001). Both a biomedical and a psychological factor were significantly associated with self-reported heart conditions in adulthood.

The impact of Yohimbine-induced arousal on facets of behavioural impulsivity

RATIONALE

State-dependent changes in physiological arousal may influence impulsive behaviours.

OBJECTIVES

To examine the relationship between arousal and impulsivity, we assessed the effects of yohimbine (an α₂-adrenergic receptor antagonist, which increases physiological arousal via noradrenaline release) on performance on established laboratory-based impulsivity measures in healthy volunteers.

METHODS

Forty-three participants received a single dose of either yohimbine hydrochloride or placebo before completing a battery of impulsivity measures. Blood pressure and heart rate were monitored throughout the study.

RESULTS

Participants in the yohimbine group showed higher blood pressure and better response inhibition in the Stop Signal Task, relative to the placebo group. Additionally, individual changes in blood pressure were associated with performance on Delay Discounting and Information Sampling tasks: raised blood pressure following drug ingestion was associated with more far-sighted decisions in the Delay Discounting Task (lower temporal impulsivity) yet reduced information gathering in the Information Sampling Task (increased reflection impulsivity).

CONCLUSIONS

These results support the notion that impulsive behaviour is dependent upon state physiological arousal; however, distinct facets of impulsivity are differentially affected by physiological changes.

Risk-Taking and Impulsivity: The Role of Mood States and Interoception

Objectives: The consequences of impulsive decisions and actions represent a major source of concern to the health and well-being of individuals and society. It is, therefore, crucial to understand the factors which contribute to impulsive behaviors. Here, we examined how personality traits of behavioral tendencies, interoceptive sensibility as well as transient mood states predict behavioral performance on impulsivity and risk-taking tasks.

Method: 574 (121 males; age 18–45) individuals completed self-report personality measures of impulsivity, reward sensitivity, punishment avoidance as well as interoceptive sensibility, undertook a mood assessment and performed a set of cognitive tasks: delay discounting (temporal impulsivity), probability discounting (risk-taking), and reflection impulsivity task. Data were interrogated using principal component analysis, correlations and regression analyses to test mutual relationships between personality traits, interoceptive sensibility, mood state and impulsive behaviors.

Results: We observed a clear separation of measures used, both trait and behavioral. Namely, sensation-seeking, reward sensitivity and probability discounting reflected risk-taking. These were separate from measures associated with impulsivity, both trait (negative and positive urgency, premeditation, perseverance) and behavioral (delayed discounting and reflection impulsivity). This separation was further highlighted by their relationship with the current emotional state: positive affect was associated with increased risk-taking tendencies and risky decision-making, while negative emotions were related to heightened impulsivity measures. Interoceptive sensibility was only associated with negative emotions component.

Conclusion: Our findings support the proposal that risk-taking and impulsivity represent distinct constructs that are differentially affected by current mood states. This novel insight enhances our understanding of impulsive behaviors.

Food and nutrient intakes by temperament traits: findings in the Helsinki Birth Cohort Study

BACKGROUND/OBJECTIVES

Previous studies have shown that the temperament traits are related to risk factors for chronic diseases, which could be partly explained by lifestyle habits. However, little is known whether temperament traits associate with diet. The aim of this study was to examine the cross-sectional associations between temperament traits and the whole diet.

SUBJECTS/METHODS

We studied 1668 men and women, aged 56-70, from the Helsinki Birth Cohort Study. Temperament was measured using the Tridimensional Personality Questionnaire. Information on diet was collected by a validated 128-item food frequency questionnaire. The associations of temperament traits; novelty seeking (NS), harm avoidance (HA), reward dependence (RD), and persistence (P), with diet were tested by linear regression analysis.

RESULTS

After adjustment for potential confounders, greater HA was related to poorer diet quality, including lower consumption of vegetables, fruits, fish and several vitamins. RD was associated with healthier diet quality, including higher consumption of vegetables and intake of vitamin E and lower intake of alcohol. NS was significantly related to higher intake of fish, fat and alcohol and lower consumption of cereals, milk products and carbohydrates. No significant associations between P and intake of foods and nutrients were observed.

CONCLUSIONS

Our results suggest that there is an association between temperament traits and diet. Especially greater HA seems to associate with poorer diet quality and greater RD with healthier diet quality.

The role of emotions and physiological arousal in modulating impulsive behaviour

Impulsivity received considerable attention in the context of drug misuse and certain neuropsychiatric conditions. Because of its great health and well-being importance, it is crucial to understand factors which modulate impulsive behaviour. As a growing body of literature indicates the role of emotional and physiological states in guiding our actions and decisions, we argue that current affective state and physiological arousal exert a significant influence on behavioural impulsivity. As 'impulsivity' is a heterogeneous concept, in this paper, we review key theories of the topic and summarise information about distinct impulsivity subtypes and their methods of assessment, pointing out to the differences between the various components of the construct. Moreover, we review existing literature on the relationship between emotional states, arousal and impulsive behaviour and suggest directions for future research.

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.

Youth temperament, harsh parenting, and variation in the oxytocin receptor gene forecast allostatic load during emerging adulthood

An association has been found between receipt of harsh parenting in childhood and adult health problems. However, this research has been principally retrospective, has treated children as passive recipients of parental behavior, and has overlooked individual differences in youth responsivity to harsh parenting. In a 10-year multiple-wave prospective study of African American families, we addressed these issues by focusing on the influence of polymorphisms in the oxytocin receptor gene (OXTR), variants of which appear to buffer or amplify responses to environmental stress. The participants were 303 youths, with a mean age of 11.2 at the first assessment, and their parents, all of whom were genotyped for variations in the rs53576 (A/G) polymorphism. Teachers rated preadolescent (ages 11 to 13) emotionally intense and distractible temperaments, and adolescents (ages 15 and 16) reported receipt of harsh parenting. Allostatic load was assessed during young adulthood (ages 20 and 21). Difficult preadolescent temperament forecast elevated receipt of harsh parenting in adolescence, and adolescents who experienced harsh parenting evinced high allostatic load during young adulthood. However, these associations emerged only among children and parents who carried A alleles of the OXTR genotype. The results suggest the oxytocin system operates along with temperament and parenting to forecast young adults' allostatic load.

Relationship between leukocyte telomere length and personality traits in healthy subjects

BACKGROUND

It has been shown that certain personality traits are related to mortality and disease morbidity, but the biological mechanism linking them remains unclear. Telomeres are tandem repeat DNA sequences located at the ends of chromosomes, and shorter telomere length is a predictor of mortality and late-life disease morbidity. Thus, it is possible that personality traits influence telomere length. In the present study, we examined the relationship of leukocyte telomere length with personality traits in healthy subjects.

SUBJECTS AND METHODS

The subjects were 209 unrelated healthy Japanese who were recruited from medical students at 4th-5th grade. Assessment of personality traits was performed by the Revised NEO Personality Inventory (NEO-PI-R) and the Temperament and Character Inventory (TCI). Leukocyte relative telomere length was determined by a quantitative real-time PCR method for a ratio of telomere/single copy gene.

RESULTS

In the stepwise multiple regression analysis, shorter telomere length was related to lower scores of neuroticism (P<0.01) and conscientiousness (P<0.05) of the NEO-PI-R, and lower scores of harm avoidance (P<0.05) and reward dependence (P<0.05) of the TCI.

CONCLUSIONS

The present study suggests that leukocyte telomere length is associated with some personality traits, and this association may be implicated in the relationship between personality traits and mortality.

Harm avoidance and cerebral infarction

OBJECTIVE

Harm avoidance, a trait indicative of behavioral inhibition, is associated with disability and dementia in old age, but the basis of these associations is uncertain. We test the hypothesis that higher level of harm avoidance is associated with increased likelihood of cerebral infarction.

METHOD

Older persons without dementia completed a standard measure of harm avoidance. During a mean of 3.5 years of follow-up, 257 (of 1,082) individuals died of whom 206 (80%) underwent brain autopsy. The number of chronic cerebral infarcts (microscopic plus gross; expressed as 0, 1, or >1) was assessed on neuropathologic examination, completed in 192 individuals at the time of analyses.

RESULTS

On postmortem examination, chronic cerebral infarcts were found in 89 (42 with 1, 47 with >1). Higher harm avoidance was associated with higher likelihood of infarcts (odds ratio = 1.083, 95% confidence interval = 1.040-1.128). A moderately high level of the trait (score = 17, 75th percentile) was associated with a 2.4-fold increase in the likelihood of infarction compared with a moderately low level of the trait (score = 6, 25th percentile). These associations persisted in models that controlled for other cardiovascular risk factors.

CONCLUSION

Higher level of the harm avoidance trait may be a risk factor for cerebral infarction.

Is impulsivity a risk factor of clinical events in acute coronary syndrome? A three-year follow-up study

OBJECTIVE

Several depressive symptoms increase the risk of adverse clinical events after acute coronary syndrome (ACS) but the potential effect of impulsivity has not been explored. The aim of the study was to investigate the effects of impulsivity on prognosis at 3-year follow-up in patients hospitalised for ACS.

METHODS

Consecutively admitted ACS patients (n=277) completed the tenth version of the Barratt Impulsivity Scale (BIS 10) and the Hospital Anxiety and Depression Scale depression subscale (HAD-D) at baseline (1-4 days after their admission). The three subscales of the BIS 10 rating motor impulsivity (motor-BIS 10), attentional impulsivity (atten-BIS 10) and nonplanning impulsivity (nonplan-BIS 10) were taken into account. Patients were followed during 3 years for adverse clinical events divided into severe cardiac events (mortality or myocardial infarction (MI)), and clinical events (mortality, MI, recurrence of ACS, hospital readmission and onset or deterioration of heart failure (HF)).

RESULTS

At follow-up, there were 135 clinical events including 40 severe cardiac events. Low motor impulsivity and high depression were associated with poor prognosis, but high levels of motor impulsivity were the only predictors of lower frequency of severe cardiac events after adjusting for demographic and clinical variables.

LIMITATIONS

The patients were recruited from only one hospital and lack of structured interview for assessment of depression.

CONCLUSIONS

Motor impulsivity predicted low incidence of severe cardiac events following ACS and the BIS can be used clinically.

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® 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.

Associations between dimensional personality measures and preclinical atherosclerosis: the cardiovascular risk in Young Finns study

OBJECTIVE

To assess how multidimensional personality-trait theories, such as the Psychobiological Model of Temperament and Character, and the Five-factor Model of Personality, are associated with subclinical atherosclerosis as indicated by carotid intima-media thickness (IMT). The analysis was designed to tolerate non-linear development in which the same personality profiles can have multiple final outcomes and different antecedent profiles can have the same final outcome.

METHODS

605 men and 844 women (average age 31.6year, s.d.=5.0, range=24-39) provided data on IMT and traits of the psychobiological model, 725 men and 1011 women were assessed for IMT and the five-factor model (age 37.7year, s.d.=5.0, range=30-45). Robust multidimensional Hotelling's T(2) statistic was used to detect personality differences between participants with high IMT and others. Model-based clustering method further explored the effect.

RESULTS

Those with a high level of subclinical atherosclerosis within the sample (highest IMT-decile) had a combined higher persistence (i.e., were perseverative or perfectionistic), more disorganized (schizotypal) character, and more antisocial temperamental configuration than others (P=0.019). No effect was found for the five-factor model (P=0.978). Traditional methods that did not account for multidimensionality and nonlinearity did not detect an association.

CONCLUSION

Psychological well-being may have positive effects on health that reduce atherosclerosis in the population as a whole. Increased subclinical atherosclerosis was associated with a profile that combines known risk factors, such as cynical distrust and hostile tendencies. More frequent use of statistical procedures that can cope with non-linear interactions in complex psychobiological systems may facilitate scientific advances in health promotion.

Cloninger's temperament traits and inherited long QT syndrome

OBJECTIVE

The long QT syndrome (LQTS) is an inherited cardiac disorder which predisposes the mutation carrier to ventricular arrhythmias that can lead to sudden death. The objective of the present study was to examine the association between the symptom status of congenital long QT syndrome mutation carriers and their temperament.

METHODS

The study subjects included 587 LQTS mutation carriers from the Finnish LQTS registry, and 2056 individuals from a database study, the Young Finns Study (YFS), representing general population and serving as control subjects. The LQTS subjects were divided into symptomatic (n=259) and asymptomatic (n=328) groups, according to their history of arrhythmic events. Temperament was assessed using the Cloninger's Temperament and Character Inventory (TCI), assessing novelty seeking, harm avoidance and reward dependence.

RESULTS

Congenital long QT syndrome mutation carriers had a higher harm avoidance (HA) than those representing the general population (2.77 vs. 2.61, p<.001, η²=0.011). Symptomatic and asymptomatic LQTS mutation carriers did not differ from one another in any of the three Cloninger's temperament traits. HA was significantly higher in women (2.72 vs. 2.54, p<0.001 η²=0.017).

CONCLUSIONS

LQTS mutation carriers may have higher stress proneness because of their high HA, which in turn may predispose them to the effects of environmental loading and thus increase the risk of arrhythmias.

Temperament dimensions in stuttering and typically developing children

PURPOSE

The purpose of this study was to determine whether children who stutter (CWS) and typically developing children (TDC) differ from each other on composite temperament factors or on individual temperament scales.

METHODS

Participants consisted of 116 age and gender-matched CWS and TDC (3.04-8.11). Temperament was assessed with a Dutch version of the Children's Behavior Questionnaire (CBQ-D; Van den Bergh and Ackx, 2003), a caregiver rating scale.

RESULTS

Results indicated significant differences between participant groups on the composite temperament factors of Negative Affectivity, and Effortful Control. Analysis of the individual temperament scales showed that CWS, compared to the TDC, scored significantly lower on the scales of 'Inhibitory Control' and 'Attentional Shifting' and higher on the scales of 'Anger/Frustration', 'Approach' and 'Motor Activation'. Stuttering severity and months of therapy were not associated with either of the temperament dimensions.

CONCLUSIONS

The present study provides data that support the hypothesis that CWS and TDC differ on both composite temperament factors and temperament scales. The findings were interpreted within existing frameworks of temperament development, as well as with regard to previous studies of temperament in CWS.

EDUCATIONAL OBJECTIVES

After reading this article, the reader will be able to: (1) describe the concept of temperament, including Rothbart's temperamental model, and its functional significance; (2) explain the CBQ-based (Children's Behavior Questionnaire) temperamental differences between CWS and CWNS; and (3) explain possible pathways for interaction between temperament and the development of stuttering.

Novelty-evoked activity in open field predicts susceptibility to helpless behavior

Learned helplessness in animals has been used to model disorders such as depression and post-traumatic stress disorder (PTSD), but there is a lack of knowledge concerning which individual behavioral characteristics at baseline can predict helpless behavior after exposure to inescapable stress. The first aim of this study was to determine behavioral predictors of helplessness using the novel and familiar open-field tests, sucrose consumption, and passive harm-avoidance tasks before learned helplessness training and testing. Individual differences in physiologic responses to restraint stress were also assessed. A cluster analysis of escape latencies from helplessness testing supported the division of the sample population of Holtzman rats into approximately 50% helpless and 50% non-helpless. Linear regression analyses further revealed that increased reactivity to the novel environment, but not general activity or habituation, predicted susceptibility to learned helplessness. During restraint stress there were no mean differences in heart rate, heart rate variability, and plasma corticosterone between helpless and non-helpless rats; however, a lower heart rate during stress was associated with higher activity levels during exploration. Our most important finding was that by using an innocuous screening tool such as the novel and familiar open-field tests, it was possible to identify subjects that were susceptible to learned helplessness.

The Relationship between Temperament and Anxiety

This study of 509 (340 female) undergraduate university students in southern Appalachia who completed the Adult Temperament Questionnaire (ATQ) and the State-Trait Anxiety Inventory (STAI), is the first phase in the development of a model to predict risk for stress-related health problems. Results indicate that high negative affect strongly predicted individuals with above average anxiety (OR = 3.7, 95% CI 2.43, 5.64), while high positive affect, effortful control, and sociability predicted that individuals would be low in reported anxiety (OR = .33 [95% CI .25, .44], .29 [95% CI .19, .45], and .69 [95% CI .56, .86], respectively).

Mediation of sensation seeking and behavioral inhibition on the relationship between heart rate and antisocial behavior: the TRAILS study

OBJECTIVE

Why is low resting heart rate (HR) associated with antisocial behavior (ASB), i.e., aggression and rule breaking, in adolescence? Theory suggests that personality traits mediate this relationship but differently with age. In the present study this age-effect hypothesis is tested; we expected that the relationship between HR and aggression would be mediated in preadolescence by the personality trait behavioral inhibition, but not by sensation seeking. However, the relationship between HR and rule breaking in adolescence was predicted to be mediated by sensation seeking, but not by behavioral inhibition. Hypotheses were tested separately for boys and girls.

METHOD

HR in supine position was assessed in repondents to the TRacking Adolescents' Individual Lives Survey (TRAILS) (N = 1,752; 48.5% boys) at age 11 years. Rule breaking and aggression at age 16 were assessed with two subscales from the Youth Self Report (YSR) questionnaire. Personality (i.e., sensation seeking and behavioral inhibition) was measured at ages 11, 13.5, and 16 with the Early Adolescent Temperament Questionnaire-Revised (EATQ-R), Behavioral Inhibition System/ Behavioral Activation System (BIS/BAS) scales, or NEO Personality-Index Revised (NEO-PI-R).

RESULTS

In boys, lower HR was associated with aggression and rule breaking in adolescence. The association between HR and rule breaking was mediated by sensation seeking in adolescence but not in preadolescence. Girls' HR was not associated with ASB, and no mediating effects were found.

CONCLUSIONS

Our findings support the age-effect hypothesis in boys' rule breaking behavior. This shows that the association between HR and ASB depends on age, gender, and subtype of ASB.