Physiological Arousal and Juvenile Psychopathy: Is Low Resting Heart Rate Associated with Affective Dimensions?

Resting heart rate moderates the relationship between parental emotion socialization and callous-unemotional traits in children

Although empirical findings have indicated that both familial and neurobiological risk factors contribute to the development of callous-unemotional (CU) traits in children, relatively few studies have investigated how these two factors interact to influence these traits. The current study focused on the combined effects of parental emotion socialization and child's resting heart rate on CU traits. Parents of Chinese children (N = 166) completed the Coping with Children's Negative Scale when children were 9.39 years old (SD = 0.92), while children's resting heart rate data were collected when they were 10.21 years old (SD = 0.72). When they were 11.15 years old (SD = 0.67), parents completed the Inventory of Callous-Unemotional Traits Short-Form. Results showed that parental supportive emotion socialization was negatively associated with CU traits and Callous behaviors in particular. In addition, resting heart rate moderated the relationship between parental emotion socialization and child's CU traits. Findings provide further evidence that an interdisciplinary approach that combines both psychosocial and biological factors is essential to further our understanding of CU traits in youth.

Diagnosing callous-unemotional personality traits by heart rate orienting responses to images inducing threat and distress

The present study aimed at developing a rather easily applicable method of testing physiological reactions to images of threats and misery. To this end, rapid-changing, transient heart rate orienting responses were used for gaining physiologically based, objective responses to the images. Additionally, subjective ratings were obtained. A significant insensitivity to other's welfare and well-being was already demonstrated as a core feature of callous-unemotional personalities. Thus, physiologically based methods may supplement and possibly improve existing assessments and, in particular, may contribute to a multimodal assessment of psychopathic traits. Out of a non-forensic community sample of 122 men, we selected two extreme groups of 30 participants with the lowest and highest callous-unemotional traits respectively, ascertained by questionnaires. As expected, participants with higher scores of callous-unemotional traits showed smaller responses to distress cues in both heart rate responses and subjective ratings. Moreover, within the group with high callous-unemotional traits heart rate responses to threatening as well as distress cues did not significantly differ from responses to neutral pictures. The study provides further evidence for the idea that a lack of responsiveness to distress cues may be seen as a central feature of callous-unemotional personalities.

Hypothalamic-pituitary-adrenal axis responsivity during adolescence in relation to psychopathic personality traits later in life

Psychopathic personality traits have been linked to low physiological arousal, particularly among high risk and forensic samples. A core indicator of physiological arousal is the activity of the hypothalamic-pituitary-adrenal (HPA) axis; however, findings of a link between HPA axis functioning and psychopathic personality traits have been inconsistent. Furthermore, given sex differences in both HPA axis responsivity and psychopathic personality traits, the association may be expected to differ between men and women. The aim of this study was to investigate the association between HPA axis responsivity in mid-adolescence and psychopathic personality traits in early adulthood and determine whether the association was moderated by sex. We examined this link in a general population sample of twins (N = 556). Adolescents participated in a psychosocial stress task during which samples of salivary cortisol were collected (11-15 years) and reported psychopathic personality traits using the Triarchic Psychopathy Measure (19-20 years). Multilevel linear regression models were estimated in which psychopathic personality traits (boldness, meanness and disinhibition), and their interactions with sex, were regressed on HPA axis responsivity. The study was pre-registered on the Open Science Framework (osf.io/gs2a8). Preliminary analyses showed that cortisol levels did not increase significantly during the stressor task but decreased during recovery. Results showed that there was no association between HPA axis responsivity in mid-adolescence and psychopathic personality traits in early adulthood. The associations were not moderated by sex. Findings suggest that HPA axis responsivity in mid-adolescence did not serve as a biological marker for psychopathic personality traits among young adults from the general population.

Psychopathic and autistic traits differentially influence the neural mechanisms of social cognition from communication signals

Psychopathy is associated with severe deviations in social behavior and cognition. While previous research described such cognitive and neural alterations in the processing of rather specific social information from human expressions, some open questions remain concerning central and differential neurocognitive deficits underlying psychopathic behavior. Here we investigated three rather unexplored factors to explain these deficits, first, by assessing psychopathy subtypes in social cognition, second, by investigating the discrimination of social communication sounds (speech, non-speech) from other non-social sounds, and third, by determining the neural overlap in social cognition impairments with autistic traits, given potential common deficits in the processing of communicative voice signals. The study was exploratory with a focus on how psychopathic and autistic traits differentially influence the function of social cognitive and affective brain networks in response to social voice stimuli. We used a parametric data analysis approach from a sample of 113 participants (47 male, 66 female) with ages ranging between 18 and 40 years (mean 25.59, SD 4.79). Our data revealed four important findings. First, we found a phenotypical overlap between secondary but not primary psychopathy with autistic traits. Second, primary psychopathy showed various neural deficits in neural voice processing nodes (speech, non-speech voices) and in brain systems for social cognition (mirroring, mentalizing, empathy, emotional contagion). Primary psychopathy also showed deficits in the basal ganglia (BG) system that seems specific to the social decoding of communicative voice signals. Third, neural deviations in secondary psychopathy were restricted to social mirroring and mentalizing impairments, but with additional and so far undescribed deficits at the level of auditory sensory processing, potentially concerning deficits in ventral auditory stream mechanisms (auditory object identification). Fourth, high autistic traits also revealed neural deviations in sensory cortices, but rather in the dorsal auditory processing streams (communicative context encoding). Taken together, social cognition of voice signals shows considerable deviations in psychopathy, with differential and newly described deficits in the BG system in primary psychopathy and at the neural level of sensory processing in secondary psychopathy. These deficits seem especially triggered during the social cognition from vocal communication signals.

Emotionality vs. Other Biobehavioural Traits: A Look at Neurochemical Biomarkers for Their Differentiation

This review highlights the differential contributions of multiple neurochemical systems to temperament traits related and those that are unrelated to emotionality, even though these systems have a significant overlap. The difference in neurochemical biomarkers of these traits is analysed from the perspective of the neurochemical model, Functional Ensemble of Temperament (FET) that uses multi-marker and constructivism principles. Special attention is given to a differential contribution of hypothalamic-pituitary hormones and opioid neuropeptides implicated in both emotional and non-emotional regulation. The review highlights the role of the mu-opioid receptor system in dispositional emotional valence and the role of the kappa-opioid system in dispositional perceptual and behavioural alertness. These opioid receptor (OR) systems, microbiota and cytokines are produced in three neuroanatomically distinct complexes in the brain and the body, which all together integrate dispositional emotionality. In contrast, hormones could be seen as neurochemical biomarkers of non-emotional aspects of behavioural regulation related to the construction of behaviour in fast-changing and current situations. As examples of the role of hormones, the review summarised their contribution to temperament traits of Sensation Seeking (SS) and Empathy (EMP), which FET considers as non-emotionality traits related to behavioural orientation. SS is presented here as based on (higher) testosterone (fluctuating), adrenaline and (low) cortisol systems, and EMP, as based on (higher) oxytocin, reciprocally coupled with vasopressin and (lower) testosterone. Due to the involvement of gonadal hormones, there are sex and age differences in these traits that could be explained by evolutionary theory. There are, therefore, specific neurochemical biomarkers differentiating (OR-based) dispositional emotionality and (hormones-based) body's regulation in fast-changing events. Here we propose to consider dispositional emotionality associated with OR systems as emotionality in a true sense, whereas to consider hormonal ensembles regulating SS and EMP as systems of behavioural orientation and not emotionality.

Heart Rate and Skin Conductance Associations with Physical Aggression, Psychopathy, Antisocial Personality Disorder and Conduct Disorder: An Updated Meta-Analysis

The associations between physiological measures (i.e., heart rate and skin conductance) of autonomic nervous system (ANS) activity and severe antisocial spectrum behavior (AB) were meta-analyzed. We used an exhaustive partitioning of variables relevant to the ANS-AB association and investigated four highly relevant questions (on declining effect sizes, psychopathy subscales, moderators, and ANS measures) that are thought to be transformative for future research on AB. We investigated a broad spectrum of physiological measures (e.g., heart rate (variability), pre-ejection period) in relation to AB. The search date for the current meta-analysis was on January 1^st, 2020, includes 101 studies and 769 effect sizes. Results indicate that effect sizes are heterogeneous and bidirectional. The careful partitioning of variables sheds light on the complex associations that were obscured in previous meta-analyses. Effects are largest for the most violent offenders and for psychopathy and are dependent on the experimental tasks used, parameters calculated, and analyses run. Understanding the specificity of physiological reactions may be expedient for differentiating between (and within) types of AB.

Functional Constructivism Approach to Multilevel Nature of Bio-Behavioral Diversity

Attempts to revise the existing classifications of psychiatric disorders (DSM and ICD) continue and highlight a crucial need for the identification of biomarkers underlying symptoms of psychopathology. The present review highlights the benefits of using a Functional Constructivism approach in the analysis of the functionality of the main neurotransmitters. This approach explores the idea that behavior is neither reactive nor pro-active, but constructive and generative, being a transient selection of multiple degrees of freedom in perception and actions. This review briefly describes main consensus points in neuroscience related to the functionality of eight neurochemical ensembles, summarized as a part of the neurochemical model Functional Ensemble of Temperament (FET). None of the FET components is represented by a single neurotransmitter; all neurochemical teams have specific functionality in selection of behavioral degrees of freedom and stages of action construction. The review demonstrates the possibility of unifying taxonomies of temperament and classifications of psychiatric disorders and presenting these taxonomies formally and systematically. The paper also highlights the multi-level nature of regulation of consistent bio-behavioral individual differences, in line with the concepts of diagonal evolution (proposed earlier) and Specialized Extended Phenotype.

Heart-wired to be cold? Exploring cardiac markers of callous-unemotional traits in incarcerated offenders

Elevated callous-unemotional (CU) traits have been repeatedly identified in a subgroup of offenders that displays severe antisocial behavior; establishing physiological markers may help improve early identification and treatment efforts. This study examines to what extent baseline-resting heart rate (HR) and heart rate variability (HRV) can be used as markers of CU in incarcerated juvenile and adult offenders. CU traits were assessed using the Inventory of Callous-Unemotional traits. Results of the multiple hierarchical regression tests indicated that there was a small yet significant positive association between baseline HR and CU and negative association between HRV and CU in juvenile offenders with medium model effect sizes (R² = 0.115 for HR-CU; R² = 0.126 for HRV-CU). The cardiac markers were unrelated to CU in adult offenders. These findings are important because they demonstrate that impaired cardiac autonomic activity is related to CU traits in juveniles, suggesting that socioemotional processing difficulties should be considered in understanding these deficits. Future research should be conducted in large samples, under reactive and static conditions, while including cardiac covariates, to get more clarity on the interplay between biological systems and behavioral expression.

Callous unemotional trait-like mice and their stressed dams

The co-occurrence of excess rates of aggression, general violation of societal norms and callous-unemotional trait confers specific risk for adult psychopathy. With the aim to address experimentally a model of conduct disorder, we investigated the male offspring of individual mouse dams characterized by high basal plasma corticosterone concentration (HC trait). Notably, classification indices correlated selectively in these females with quite poor maternal care devoted to their offspring. Contrary to their HC mothers, adult male offspring exhibited an integrated profile of dampened physiological reactivity to external stressors co-occurring poor sociability/emotional contagion, impaired punishment-induced memory, and exacerbated aggression. A significant reduction of glucocorticoid and opioid mu receptors' expression in frontal cortex of model HC offspring was also evidenced. Moreover, in the absence of changes in oxytocin receptor in behaviorally-relevant neural areas, we showed that intranasal oxytocin administration (0 or 20.0 µg/kg) selectively modulated specific components of the behavioral phenotype. Ultimately, current data support the notion that maternally-inoculated environmental stress early in development may represent a critical risk factor in disturbances characterised by abnormal aggression and excess callousness.

The causal nature of the association between resting pulse in late adolescence and risk for internalizing and externalizing disorders: a co-relative analysis in a national male Swedish sample

BACKGROUND

Resting pulse is robustly and inversely associated with the risk for externalizing disorders and may be positively associated with internalizing disorders. We know little about the causal nature of these associations.

METHODS

We examined resting pulse at conscription examination in 369 301 males born 1960-80 with a mean (s.d.) follow-up of 29.1 (7.7) years. From pulse rates, we predicted, using Cox models, the risk for criminal behavior (CB), drug abuse (DA), alcohol use disorder (AUD), major depression (MD), and anxiety disorders (AD), assessed from medical, criminal, and pharmacy registries. Co-relative analyses were conducted on the general population, cousin, half-sibling, full-sibling, and monozygotic pairs discordant for the outcome. Twin/sibling modeling for pulse was performed using OpenMX.

RESULTS

Familial resemblance for pulse resulted entirely from genetic factors. In the general population, the risk for externalizing disorders (CB, DA, and AUD) and internalizing disorders (MD and AD) were, respectively, significantly associated with low and high resting pulse rate. For CB, DA, and AUD, co-relative analyses showed that the inverse association with pulse resulted entirely from familial common causes (aka 'confounders'). By contrast, co-relative analyses found that the association between higher pulse and MD and AD resulted from direct causal effects.

CONCLUSIONS

Resting pulse has a negative and positive association with, respectively, the risk for externalizing and for internalizing disorders. Co-relative analyses indicate that the nature of these associations differ, suggesting that elevated pulse appears to directly increase the risk for internalizing disorders while the reduced pulse is a risk index for underlying traits that predispose to externalizing disorders.

Resting Heart Rate Mediates the Relationship between Parenting Style and Callous-Unemotional Traits in Chinese Children

Despite increasing knowledge of social and biological risk factors for callous-unemotional (CU) traits, relatively less is known about how these two sets of risk factors combine to affect these traits. The current longitudinal study investigated pathways from parenting style to CU traits via resting heart rate in a three-year project. Parents of 382 children completed the Parenting Styles and Dimensions Questionnaire at Time 1 (children Mean age = 9.06, SD = 0.94, range = 7-11 years), with the heart rate data collected at Time 2 (M = 10.16, SD = 0.93, range = 8-13 years) and CU traits assessed at Time 3 (M = 11.06, SD = 0.94, range = 9-13 years). We found that parenting style and CU traits were associated with resting heart rate, and that structural equation modeling showed resting heart rate to partially mediate the effect of parenting style on CU traits. Specifically, higher levels of authoritarian parenting were associated with lower resting heart rate, which in turn was linked to higher level of CU traits. On the contrary, children in the context of authoritative parenting showed relatively higher resting heart rate, which was predictive of lower CU traits. Overall, findings have implications for understanding the etiology of CU traits in children and developing effective prevention programs for children with affective deficits.

Resting Heart Rate and Psychopathy Revisited: Findings From the Add Health Survey

Despite the prior linkages of low resting heart rate to antisocial behavior broadly defined, less work has been done examining possible associations between heart rate to psychopathic traits. The small body of research on the topic that has been conducted so far seems to suggest an inverse relationship between the two constructs. A smaller number of studies has found the opposite result, however, and some of the previous studies have been limited by small sample sizes and unrepresentative samples. The current study attempts to help clarify the relationship between resting heart rate and psychopathic traits in a large, nationally representative sample (analytical N ranged from 14,173-14,220) using an alternative measure of psychopathic traits that is less focused on antisocial processes, and rooted in personality traits. No significant relationship between heart rate and psychopathic traits, or heart rate and a measure of cold-heartedness, was found. It is possible that previous findings of a link between heart rate and psychopathy have been driven by the inclusion of overt antisocial behavior in many traditional psychopathy measures. Further work is needed to confirm the associations (or lack thereof) between heart rate and the behavioral, affective, and personality trait aspects of psychopathy.

Adolescent psychopathy, heart rate, and skin conductance

Researchers have advocated for a greater focus on measuring neurobiological underpinnings of serious psychological conditions such as psychopathy. This has become particularly important to investigate early in the life span, when intervention efforts for psychopathy-related behavior like conduct disorder (CD) are more successful. Given that psychopathy is a complex syndrome, it is also important to investigate physiological processes at a dimensional level. Using a sample of 56 adolescent male offenders (M_age = 15.92; SD = 1.31), this study explored the relationship between the Psychopathy Checklist-Youth Version (Forth, Kosson, & Hare, 2003), heart rate (HR), and skin conductance (SC). A white noise countdown task was used to measure autonomic activity across a baseline, anticipatory (prenoise), and reactivity (postnoise) period. Findings revealed no significant associations between psychopathy and HR activity across the time intervals. However, results revealed a positive association between grandiose-manipulative traits and SC activity and a negative association between callous-unemotional traits and SC activity. The results indicate that autonomic processes may contribute to distinct psychopathic traits in different ways, implicating slightly differential brain functioning. The findings suggest that, in order to better understand and treat youth with CD, future research should continue to examine the biological correlates of psychopathy at the broader construct level but perhaps especially at the component level.

Valence, arousal or both? Shared emotional deficits associated with Attention Deficit and Hyperactivity Disorder and Oppositional/Defiant-Conduct Disorder symptoms in school-aged youth

We examined emotional responses in Attention Deficit Hyperactivity and Oppositional Defiant/Conduct Disorder to affective pictures. Eighty seven children (42 female, M_age = 11.2), with clinical or subclinical symptoms and controls viewed joy, fear, sadness or neutral pictures while heart rate, skin conductance, corrugator and zygomaticus responses were recorded. The moderating role of Callous-Unemotional and anxiety traits was evaluated. Lower resting heart rate and decreased skin conductance across picture types was associated with ADHD symptoms. Decreased heart rate reactivity to fear and sad stimuli was associated with ADHD and ODD/CD. Corrugator and zygomaticus responses were not associated with ADHD or ODD/CD. Findings are mostly consistent with a fearlessness account of disruptive behavior, and seem to also pertain to ADHD, with intact valence systems. Findings are discussed in light of the significance of identifying common pathogenic mechanisms across traditional diagnostic categories, consistent with trans-diagnostic approaches to the study of psychopathology.

Low resting heart rate, sensation seeking and the course of antisocial behaviour across adolescence and young adulthood

BACKGROUND

Low resting heart rate (RHR) is a consistent biological correlate of antisocial behaviour (ASB), however potential mechanisms have been largely unexplored. We hypothesise that lower RHR will be associated with higher ASB levels in mid-adolescence and persistence into adulthood, and that these associations will be explained, in part, by sensation seeking and callous-unemotional traits.

METHODS

ASB was assessed repeatedly with young people from ages 15 to 21 years in a population-based birth cohort (ALSPAC). A longitudinal trajectory was derived and showed ASB decreasing across adolescence before stabilising in early adulthood. RHR was recorded at age 12 years, and mediators were assessed at age 14 years.

RESULTS

After adjusting for socio-demographic confounders, there was evidence for a total effect of RHR on ASB levels in mid-adolescence [b(95% CI) = -0.08 (-0.14 to -0.02)], reflecting 0.08 more types of antisocial activity in the last year per 10 fewer heart beats per minute. This effect was almost entirely explained through sensation seeking [b(95% CI) = -0.06 (-0.08 to -0.04)]. After additionally adjusting for child and parent-related confounders, all effects weakened; however, there was still evidence of an indirect effect of RHR, via sensation seeking, on ASB levels in mid-adolescence [b(95% CI) = -0.01 (-0.03 to -0.003)]. There was no evidence for a total effect of RHR on ASB levels in early adulthood, and weak evidence of an indirect effect, via sensation seeking [b(95% CI) = -0.01 (-0.01 to -0.00)].

CONCLUSIONS

Lower RHR in childhood was associated with higher ASB levels in mid-adolescence, indirectly via sensation seeking.

The Reliability and Validity of the Inventory of Callous Unemotional Traits: A Meta-Analytic Review

In the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders, a Limited Prosocial Emotions specifier was added to the conduct disorder diagnostic criteria to designate a subgroup of children who exhibit callous unemotional (CU) traits. The Inventory of Callous Unemotional Traits (ICU) is the only dedicated measure of CU traits and was influential in the development of the Limited Prosocial Emotions specifier. Despite its role in the research and diagnosis of CU traits, some questions have persisted regarding the internal consistency and validity of the ICU and its three subscales: callous, uncaring, and unemotional. Results of a meta-analysis revealed acceptable internal consistency and external validity for total ICU, callous, and uncaring scores, but not unemotional scores. These results support the utility of the total ICU, callous, and uncaring scales, but indicate weaknesses in the scale or construct of unemotionality as it relates to interpersonal callousness, uncaring, and antisociality.

Pupil-size asymmetry is a physiologic trait related to gender, attentional function, and personality

A small difference in the size of the two pupils is common in healthy individuals, a condition termed benign or physiologic anisocoria (BA). Past research indicates that BA is probably caused by asymmetry in sympathetic nervous system (SNS) function [e.g., Rosenberg (2008). Physiologic anisocoria: A manifestation of a physiologic sympathetic asymmetry. Neuro-Ophthalmology, 32, 147-149]. This study is the first to show that BA varies with psychological factors linked to brain asymmetry and autonomic arousal, including gender, attention, and personality. Males exhibited a more directional BA than females, consistent with greater hemispheric lateralization in males. BA also varied with a self-report measure of attentional function, consistent with evidence of hemispheric asymmetry in visuospatial attention networks. Finally, BA varied with personality traits linked to autonomic arousal. Individuals exhibiting higher Meanness and Boldness, and lower Empathy scores tended to show more directional BA. This link between personality traits and BA may be related to brain asymmetries in autonomic arousal and emotion-related processing. If future studies employing direct measures of lateralized brain activity confirm the link between BA and SNS asymmetries, this new metric may prove useful in discovering new relationships between brain organization and psychological function, and how these relationships vary across individuals.