Callous and uncaring traits are associated with reductions in amygdala volume among youths with varying levels of conduct problems

The amygdala volume moderates the relationship between childhood maltreatment and callous-unemotional traits in adolescents with conduct disorder

CU traits, characterized by shallow affect, lack of fear, and absence of remorse, have been moderately associated with childhood maltreatment in a recent meta-analysis. However, the potential impact of brain structures remains undetermined. This paper examines the relationship between callous-unemotional (CU) traits, childhood maltreatment, and amygdala volumes. In this study, we used a region-of-interest (ROI) analysis to explore the interaction between the volumes of the amygdala, childhood maltreatment, and the manifestation of CU traits in adolescents diagnosed with conduct disorder (CD, N = 67), along with a comparison group of healthy-control youths (HCs, N = 89). The ROI analysis revealed no significant group differences in the bilateral amygdalar volumes. Significant positive correlation was discovered between all forms of child maltreatment (except for physical neglect) and CU traits across subjects. But the interaction of physical abuse and amygdala volumes was only significant within CD patients. Notably, a sensitivity analysis suggested that gender significantly influences these findings. These results contribute critical insights into the etiology of CU traits, emphasizing the need for customized clinical assessment tools and intervention strategies.

Dynamic Amygdala Nuclei Alterations in Relation to Weight Status in Anorexia Nervosa Are Mediated by Leptin

OBJECTIVE

The amygdaloid complex is a subcortical limbic group of distinct nuclei. In a previous patient-control study, differential amygdala nuclei alterations were found in acute anorexia nervosa (AN); rostral-medial nuclei involved in fear and reward processing were substantially reduced in volume and associated with hypoleptinemia, a key neuroendocrine characteristic of AN. Here, longitudinal amygdala nuclei alterations in AN were investigated in relation to weight status and their associations with leptin levels.

METHOD

T1-weighted structural magnetic resonance imaging scans were longitudinally processed with FreeSurfer. Amygdala nuclei volumes in young female patients with acute AN before and after short-term weight restoration (n = 110, >14% body mass index increase over 3 months) and female participants with a history of AN (n = 79, long-term [mean 5 years] weight recovered) were compared with female healthy control participants (n = 271) using linear mixed effects models.

RESULTS

Rostral-medially clustered amygdala nuclei volumes, accessory basal, cortical, medial nuclei, and corticoamygdaloid transition, increased during short-term weight restoration (Cohen's d range 0.18-0.30). However, volumetric normalization across nuclei was heterogeneous. Right cortical, medial nuclei, bilateral corticoamygdaloid transitions, and anterior amygdaloid areas were only partially normalized following short-term weight restoration. Right anterior amygdaloid area remained reduced after long-term weight recovery compared with control participants (d = 0.36). Leptin increase, accompanying short-term weight restoration, mediated the effect of weight gain on volumetric increase in left corticoamygdaloid transition and bilateral medial nuclei.

CONCLUSION

Rostral-medially clustered amygdala nuclei show pronounced volumetric increase but incomplete normalization in AN during and after short-term weight restoration. Leptin increase may be relevant for the recovery of specific amygdala nuclei in addition to nutritional rehabilitation, indicating links between amygdala substructure and leptin dynamics of potential pathophysiological and clinical relevance in AN.

PLAIN LANGUAGE SUMMARY

The amygdala plays a critical role in processing fearful and rewarding stimuli, and alterations in the amygdala are associated with anorexia nervosa. In this study, the authors measured amygdala nuclei volumes in female patients with acute anorexia nervosa undergoing weight-restoration treatment (n = 110), long-term weight-recovered individuals with anorexia (n = 79), and healthy control participants (n = 271). Structural magnetic resonance imaging revealed that volumes of specific nuclei, clustered in the rostral-medial amygdala, were substantially reduced in acute anorexia nervosa and only partially normalized following weight restoration treatment. Residual reductions in volume persisted even after long-term weight-recovery, compared to healthy control participants. Short-term weight restoration was associated with increases in the neurohormone leptin, and increasing leptin levels were found to mediate the positive impact of weight gain on increased amygdala volume over the treatment course.

DIVERSITY & INCLUSION STATEMENT

We worked to ensure race, ethnic, and/or other types of diversity in the recruitment of human participants. We worked to ensure that the study questionnaires were prepared in an inclusive way. One or more of the authors of this paper received support from a program designed to increase minority representation in science. We actively worked to promote sex and gender balance in our author group. We actively worked to promote inclusion of historically underrepresented racial and/or ethnic groups in science in our author group. While citing references scientifically relevant for this work, we also actively worked to promote sex and gender balance in our reference list. While citing references scientifically relevant for this work, we also actively worked to promote inclusion of historically underrepresented racial and/or ethnic groups in science in our reference list. The author list of this paper includes contributors from the location and/or community where the research was conducted who participated in the data collection, design, analysis, and/or interpretation of the work.

Brain Anatomy in Boys with Conduct Disorder: Differences Among Aggression Subtypes

Aggression is a core feature of conduct disorder (CD), but the motivation, execution of aggression may vary. A deeper understanding of the neural substrates of aggressive behaviours is critical for effective clinical intervention. Seventy-six Boys with CD (50 with impulsive aggression (I-CD) and 26 with premeditated aggression (P-CD)) and 69 healthy controls (HCs) underwent a structural MRI scan and behavioural assessments. Whole-brain analyses revealed that, compared to HCs, the I-CD group showed significant cortical thinning in the right frontal cortex, while the P-CD group demonstrated significant folding deficits in the bilateral superior parietal cortex. Both types of aggression negatively correlated with the left amygdala volume, albeit in different ways. The present results demonstrated that the complex nature of aggression relies on differentiated anatomical substrates, highlighting the importance of exploring differential circuit-targeted interventions for CD patients.

Empathy deficits, callous-unemotional traits and structural underpinnings in autism spectrum disorder and conduct disorder youth

Distinct empathy deficits are often described in patients with conduct disorder (CD) and autism spectrum disorder (ASD) yet their neural underpinnings and the influence of comorbid Callous-Unemotional (CU) traits are unclear. This study compares the cognitive (CE) and affective empathy (AE) abilities of youth with CD and ASD, their potential neuroanatomical correlates, and the influence of CU traits on empathy. Adolescents and parents/caregivers completed empathy questionnaires (N = 148 adolescents, mean age = 15.16 years) and T1 weighted images were obtained from a subsample (N = 130). Group differences in empathy and the influence of CU traits were investigated using Bayesian analyses and Voxel-Based Morphometry with Threshold-Free Cluster Enhancement focusing on regions involved in AE (insula, amygdala, inferior frontal gyrus and cingulate cortex) and CE processes (ventromedial prefrontal cortex, temporoparietal junction, superior temporal gyrus, and precuneus). The ASD group showed lower parent-reported AE and CE scores and lower self-reported CE scores while the CD group showed lower parent-reported CE scores than controls. When accounting for the influence of CU traits no AE deficits in ASD and CE deficits in CD were found, but CE deficits in ASD remained. Across all participants, CU traits were negatively associated with gray matter volumes in anterior cingulate which extends into the mid cingulate, ventromedial prefrontal cortex, and precuneus. Thus, although co-occurring CU traits have been linked to global empathy deficits in reports and underlying brain structures, its influence on empathy aspects might be disorder-specific. Investigating the subdimensions of empathy may therefore help to identify disorder-specific empathy deficits.

Conduct problems among middle adolescents in the community settings: A concept analysis

Background

Adolescent problem behavior in research and practice has been traditionally categorized as Oppositional Deviant Disorder and Conduct Disorder. However, a significant number of adolescents remain underdiagnosed. To address this issue, the term "Conduct Problem" has emerged as a commonly used descriptor for those who have not yet received a formal diagnosis, particularly within the community. It is crucial for nurses to comprehend the characteristics of these conduct problems to address them effectively.

Objective

This concept analysis aimed to clarify the concept of conduct problems among adolescents aged 14 to 16, specifically within community settings.

Methods

The concept analysis followed Walker and Avant's approach. The usage of the concept was examined in five databases (PsyINFO, ProQuest, PubMed, ScienceDirect, Scopus), which yielded 41 relevant studies for comprehensive analysis.

Results

The identified attributes of conduct problems in adolescents included oppositional problems, antisocial problems, and criminal-related problems. These conduct problems were found to have antecedents stemming from personal, parental, and environmental factors. Furthermore, the consequences of conduct problems significantly impacted both middle adolescents and their parents.

Conclusion

The findings of this concept analysis contribute to a better comprehension of the concept of conduct problems among middle adolescents in community settings. The insights gained from this analysis will assist in using this term more effectively in research and nursing practice, ultimately leading to improved care and support for affected adolescents and their families.

Urbach-Wiethe disease in a young patient without apparent amygdala calcification

Urbach-Wiethe disease is an extremely rare genetically-based syndrome which usually leads to dermatological and neurological changes. Neurologically, the amygdaloid region is primarily bilaterally affected. Therefore, several functions modulated by the amygdala are changed in patients with Urbach-Wiethe disease. As the neurological alterations evolve only gradually, it is particularly important to determine the cognitive and brain status of a juvenile. The patient described here was seen briefly at age 9 and tested neuropsychologically at age 19; furthermore, computer tomography and magnetic resonance imaging of his head was done. There were no important abnormalities in the brain, which is unusual in the light of previous data from other patients. On the cognitive level, the patient was generally within normal limits. However, he had mild problems in attention and concentration, and more prominent problems in emotional processing domain, and in personality dimensions. It is concluded that amygdala calcifications in Urbach-Wiethe disease take place progressively-possibly underpinned by genetic and gender variables; this can subsequently allow psychosocial-social factors (such a proper education and socialization) and biological factors (compensatory neuroplasticity) to retard and diminish the development of socio-emotional and cognitive deteriorations, though the outcome of questionnaires indicates that such patients may develop substantial concerns as to their future life and well-being.

Structural abnormalities in adolescents with conduct disorder and high versus low callous unemotional traits

There may be distinct conduct disorder (CD) etiologies and neural morphologies in adolescents with high callous unemotional (CU) traits versus low CU traits. Here, we employed surface-based morphometry methods to investigate morphological differences in adolescents diagnosed with CD [42 with high CU traits (CD-HCU) and 40 with low CU traits (CD-LCU)] and healthy controls (HCs, N = 115) in China. Whole-brain analyses revealed significantly increased cortical surface area (SA) in the left inferior temporal cortex and the right precuneus, but decreased SA in the left superior temporal cortex in the CD-LCU group, compared with the HC group. There were no significant cortical SA differences between the CD-HCU and the HC groups. Compared to the CD-HCU group, the CD-LCU group had a greater cortical thickness (CT) in the left rostral middle frontal cortex. Region-of-interest analyses revealed significant group differences in the right hippocampus, with CD-HCU group having lower right hippocampal volumes than HCs. We did not detect significant group differences in the amygdalar volume, however, the right amygdalar volume was found to be a significant moderator of the correlation between CU traits and the proactive aggression in CD patients. The present results suggested that the manifestations of CD differ between those with high CU traits versus low CU traits, and underscore the importance of sample characteristics in understanding the neural substrates of CD.

How reliable are amygdala findings in psychopathy? A systematic review of MRI studies

The amygdala is a key component in predominant neural circuitry models of psychopathy. Yet, after two decades of neuroimaging research on psychopathy, the reproducibility of amygdala findings is questionable. We systematically reviewed MRI studies (81 of adults, 53 of juveniles) to determine the consistency of amygdala findings across studies, as well as within specific types of experimental tasks, community versus forensic populations, and the lowest- versus highest-powered studies. Three primary findings emerged. First, the majority of studies found null relationships between psychopathy and amygdala structure and function, even in the context of theoretically relevant tasks. Second, findings of reduced amygdala activity were more common in studies with low compared to high statistical power. Third, the majority of peak coordinates of reduced amygdala activity did not fall primarily within the anatomical bounds of the amygdala. Collectively, these findings demonstrate significant gaps in the empirical support for the theorized role of the amygdala in psychopathy and indicate the need for novel research perspectives and approaches in this field.

Parenting practices moderate the link between attention to the eyes and callous unemotional traits in children with Disruptive Behavior Disorder: An eye-tracking study

Callous-unemotional (CU) traits are associated with gaze pattern deficits in youths, though it has not yet been explored if environmental factors could influence this relationship. Since parenting can influence both CU traits and children's emotion processing, the current study sought to test whether parenting moderated the relation between gaze pattern deficits and CU traits in a sample of children with Disruptive Behavior Disorder. The sample included 92 boys (aged 7-12 years) with Conduct Disorder (N = 12) and Oppositional Defiant Disorder (N = 80). All children completed a task, during which they were presented with 24 images depicting happy, sad, fearful, disgusted, angry, and neutral facial expressions. Gaze pattern has been recorded throughout the task with an eye-tracker. Positive parenting moderated the association between CU traits and first fixation duration to the eyes of facial expressions depicting negative emotions. Negative parenting moderated the association between CU traits and fixation count and fixation duration to the eyes of negative emotions. Negative parenting along with reduced attention to emotional cues (i.e., eyes) may identify a group of youths with Disruptive Behavior Disorder diagnosis at risk for severe outcomes.

Conduct problems among children in low-income, urban neighborhoods: A developmental psychopathology- and RDoC-informed approach

Conduct problems are associated with numerous negative long-term psychosocial sequelae and are among the most frequent referrals for children's mental health services. Youth residing in low-income, urban communities are at increased risk for conduct problems, but not all youth in these environments develop conduct problems, suggesting heterogeneity in risk and resilience processes and developmental pathways. The present study used a developmental psychopathology- and Research Domain Criteria (RDoC)-informed approach for conceptualizing risk and resilience for conduct problems among children from low-income, urban neighborhoods. Participants were 104 children (M = 9.93 ± 1.22 years; 50% male; 96% African American, 4% Latinx). We assessed four constructs reflecting cognitive and neurobiological processes associated with conduct problems using multiple levels of analysis and informants: autonomic nervous system reactivity, limbic system/orbitofrontal cortical functioning, dorsolateral prefrontal cortical functioning, and conduct problems. Latent profile analysis identified four profiles: typically developing (TD, n = 34); teacher-reported conduct problems (TCP, n = 14); emotion processing (EP, n = 27); and emotion expression recognition (EER, n = 29). External validation analyses demonstrated that profiles differed on various indices of conduct problems in expected ways. The EP profile exhibited lower levels of emotional lability and callous–unemotional behaviors, and higher levels of prosocial behavior. The TD profile demonstrated elevated emotional lability. Implications for etiological and intervention models are presented.

Resting-state network topology characterizing callous-unemotional traits in adolescence

BACKGROUND

Callous-unemotional (CU) traits, a youth antisocial phenotype, are hypothesized to associate with aberrant connectivity (dis-integration) across the salience (SAL), default mode (DMN), and frontoparietal (FPN) networks. However, CU traits have a heterogeneous presentation and previous research has not modeled individual heterogeneity in resting-state connectivity amongst adolescents with CU traits. The present study models individual-specific network maps and examines topological features of individual and subgroup maps in relation to CU traits.

METHODS

Participants aged 13-17 (n = 84, male = 55%, female = 45%) completed resting-state functional connectivity and the inventory of callous-unemotional traits as part of the Nathan Klein Rockland study. A sparse network approach (GIMME) was used to derive individual-level and subgroup maps of all participants. We then examined heterogeneous network features, including positive and negative connection density, associated with CU traits.

RESULTS

Higher rates of CU traits increased probability of inclusion in one subgroup, which had the highest mean level of CU traits. Analysis of network features reveals less density (positive and negative) within the FPN and greater density between DMN-FPN associated with CU traits.

DISCUSSION

Findings indicate heterogeneous person-specific connections and some subgroup connections amongst adolescents associate with CU traits. Higher CU traits associate with lower density in the FPN, which has been associated with attention and inhibition, and higher density between the DMN-FPN, which have been linked with cognitive control, social working memory, and empathy. Our findings suggest less efficiency in FPN function which, when considered mechanistically, could result in difficulty suppressing DMN when task positive networks are engaged. This is an area for further exploration but could explain cognitive and socio-affective impairments in CU traits.

Reflexive Gaze Shifts and Fear Recognition Deficits in Children with Callous-Unemotional Traits and Impulsivity/Conduct Problems

The ability to efficiently recognize the emotions on others' faces is something that most of us take for granted. Children with callous-unemotional (CU) traits and impulsivity/conduct problems (ICP), such as attention-deficit hyperactivity disorder, have been previously described as being "fear blind". This is also associated with looking less at the eye regions of fearful faces, which are highly diagnostic. Previous attempts to intervene into emotion recognition strategies have not had lasting effects on participants' fear recognition abilities. Here we present both (a) additional evidence that there is a two-part causal chain, from personality traits to face recognition strategies using the eyes, then from strategies to rates of recognizing fear in others; and (b) a pilot intervention that had persistent effects for weeks after the end of instruction. Further, the intervention led to more change in those with the highest CU traits. This both clarifies the specific mechanisms linking personality to emotion recognition and shows that the process is fundamentally malleable. It is possible that such training could promote empathy and reduce the rates of antisocial behavior in specific populations in the future.

Psychopathy

Psychopathy is a personality disorder characterized by a constellation of affective, interpersonal, lifestyle and antisocial features whose antecedents can be identified in a subgroup of young people showing severe antisocial behaviour. The prevalence of psychopathy in the general population is thought to be ~1%, but is up to 25% in prisoners. The aetiology of psychopathy is complex, with contributions of both genetic and environmental risk factors, and gene-environment interactions and correlations. Psychopathy is characterized by structural and functional brain abnormalities in cortical (such as the prefrontal and insular cortices) and subcortical (for example, the amygdala and striatum) regions leading to neurocognitive disruption in emotional responsiveness, reinforcement-based decision-making and attention. Although no effective treatment exists for adults with psychopathy, preliminary intervention studies targeting key neurocognitive disturbances have shown promising results. Given that psychopathy is often comorbid with other psychiatric disorders and increases the risk of physical health problems, educational and employment failure, accidents and criminality, the identification of children and young people at risk for this personality disorder and preventative work are important. Indeed, interventions that target the antecedents of psychopathic features in children and adolescents have been found to be effective.

Validity and utility of Hierarchical Taxonomy of Psychopathology (HiTOP): II. Externalizing superspectrum

The Hierarchical Taxonomy of Psychopathology (HiTOP) is an empirical effort to address limitations of traditional mental disorder diagnoses. These include arbitrary boundaries between disorder and normality, disorder co-occurrence in the modal case, heterogeneity of presentation within dis-orders, and instability of diagnosis within patients. This paper reviews the evidence on the validity and utility of the disinhibited externalizing and antagonistic externalizing spectra of HiTOP, which together constitute a broad externalizing superspectrum. These spectra are composed of elements subsumed within a variety of mental disorders described in recent DSM nosologies, including most notably substance use disorders and "Cluster B" personality disorders. The externalizing superspectrum ranges from normative levels of impulse control and self-assertion, to maladaptive disinhibition and antagonism, to extensive polysubstance involvement and personality psychopathology. A rich literature supports the validity of the externalizing superspectrum, and the disinhibited and antagonistic spectra. This evidence encompasses common genetic influences, environmental risk factors, childhood antecedents, cognitive abnormalities, neural alterations, and treatment response. The structure of these validators mirrors the structure of the phenotypic externalizing superspectrum, with some correlates more specific to disinhibited or antagonistic spectra, and others relevant to the entire externalizing superspectrum, underlining the hierarchical structure of the domain. Compared with traditional diagnostic categories, the externalizing superspectrum conceptualization shows improved utility, reliability, explanatory capacity, and clinical applicability. The externalizing superspectrum is one aspect of the general approach to psychopathology offered by HiTOP and can make diagnostic classification more useful in both research and the clinic.

Core features of callous-unemotional traits: Network analysis of the inventory of callous-unemotional traits in offender and community samples

OBJECTIVE

Callous-unemotional (CU) traits have been added as a specifier labeled with "Limited Prosocial Emotion" used to diagnose conduct disorder in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders. However, little is known about the core features of CU traits. Thus, this study aimed to identify the most central component of CU traits from a network perspective.

METHOD

Network analysis was applied to investigate the network structure of CU traits operationalized by the Inventory of Callous-Unemotional Traits in a sample of juvenile offenders (M_age  = 17.14, N = 609) and community youths (M_age  = 10.82, N = 487).

RESULTS

Our findings showed that items assessing callousness are the most central in the network across both samples. Also, the unemotional items were found to be located at a peripheral position, with fewer links apparent to callousness and uncaring items.

CONCLUSIONS

Callousness might be the key feature of CU traits in youths. Our findings further advance the general understanding about the core features of CU traits in clinical practice.

Mapping neural activity patterns to contextualized fearful facial expressions onto callous-unemotional (CU) traits: intersubject representational similarity analysis reveals less variation among high-CU adolescents

Callous-unemotional (CU) traits are early-emerging personality features characterized by deficits in empathy, concern for others, and remorse following social transgressions. One of the interpersonal deficits most consistently associated with CU traits is impaired behavioral and neurophysiological responsiveness to fearful facial expressions. However, the facial expression paradigms traditionally employed in neuroimaging are often ambiguous with respect to the nature of threat (i.e., is the perceiver the threat, or is something else in the environment?). In the present study, 30 adolescents with varying CU traits viewed fearful facial expressions cued to three different contexts ("afraid for you," "afraid of you," "afraid for self") while undergoing functional magnetic resonance imaging (fMRI). Univariate analyses found that mean right amygdala activity during the "afraid for self" context was negatively associated with CU traits. With the goal of disentangling idiosyncratic stimulus-driven neural responses, we employed intersubject representational similarity analysis to link intersubject similarities in multivoxel neural response patterns to contextualized fearful expressions with differential intersubject models of CU traits. Among low-CU adolescents, neural response patterns while viewing fearful faces were most consistently similar early in the visual processing stream and among regions implicated in affective responding, but were more idiosyncratic as emotional face information moved up the cortical processing hierarchy. By contrast, high-CU adolescents' neural response patterns consistently aligned along the entire cortical hierarchy (but diverged among low-CU youths). Observed patterns varied across contexts, suggesting that interpretations of fearful expressions depend to an extent on neural response patterns and are further shaped by levels of CU traits.

Callous-unemotional traits and reduced default mode network connectivity within a community sample of children

Callous-unemotional (CU) traits characterize a subset of youth at risk for persistent and serious antisocial behavior. Differences in resting state connectivity in the default mode network (DMN) have been associated with CU traits in forensic and clinical samples of adolescents and with deficient interpersonal/affective traits (often operationalized as Factor 1 psychopathy traits) in adults. It is unclear whether these brain-behavior associations extend to community-based children. Using mixed model analyses, we tested the associations between CU traits and within-network resting-state connectivity of seven task-activated networks and the DMN using data from 9,636 9-11-year-olds in the Adolescent Brain Cognitive Development (ABCD) study. Even after accounting for comorbid externalizing problems, higher levels of CU traits were associated with reduced connectivity within the DMN. This finding is consistent with prior literature surrounding psychopathy and CU traits in clinically and forensically based populations, suggesting the correlation likely exists on a spectrum, can be detected in childhood, and is not restricted to children with significant antisocial behavior.

Specific cortical and subcortical alterations for reactive and proactive aggression in children and adolescents with disruptive behavior

Maladaptive aggression, as present in conduct disorder (CD) and, to a lesser extent, oppositional defiant disorder (ODD), has been associated with structural alterations in various brain regions, such as ventromedial prefrontal cortex (vmPFC), anterior cingulate cortex (ACC), amygdala, insula and ventral striatum. Although aggression can be subdivided into reactive and proactive subtypes, no neuroimaging studies have yet investigated if any structural brain alterations are associated with either of the subtypes specifically. Here we investigated associations between aggression subtypes, CU traits and ADHD symptoms in predefined regions of interest.

T1-weighted magnetic resonance images were acquired from 158 children and adolescents with disruptive behavior (ODD/CD) and 96 controls in a multi-center study (aged 8–18). Aggression subtypes were assessed by questionnaires filled in by participants and their parents. Cortical volume and subcortical volumes and shape were determined using Freesurfer and the FMRIB integrated registration and segmentation tool. Associations between volumes and continuous measures of aggression were established using multilevel linear mixed effects models.

Proactive aggression was negatively associated with amygdala volume (b = -10.7, p = 0.02), while reactive aggression was negatively associated with insula volume (b = -21.7, p = 0.01). No associations were found with CU traits or ADHD symptomatology. Classical group comparison showed that children and adolescents with disruptive behavior had smaller volumes than controls in (bilateral) vmPFC (p = 0.003) with modest effect size and a reduced shape in the anterior part of the left ventral striatum (p = 0.005).

Our study showed negative associations between reactive aggression and volumes in a region involved in threat responsivity and between proactive aggression and a region linked to empathy. This provides evidence for aggression subtype-specific alterations in brain structure which may provide useful insights for clinical practice.

Disruptive Behavior Problems, Callous-Unemotional Traits, and Regional Gray Matter Volume in the Adolescent Brain and Cognitive Development Study

BACKGROUND

Neurobiological differences linked to socioemotional and cognitive processing are well documented in youths with disruptive behavior disorders (DBDs), especially youths with callous-unemotional (CU) traits. The current study expanded this literature by examining gray matter volume (GMV) differences among youths with DBD with CU traits (DBDCU+), youths with DBD without CU traits (DBD-only), and youths that were typically developing (TD).

METHODS

Data were from the first full sample release of the Adolescent Brain and Cognitive Development Study (mean age = 9.49 years; 49% female). We tested whether the GMVs of 11 regions of interest selected a priori differentiated between our 3 groups: DBDCU+ (n = 288), DBD-only (n = 362), and TD (n = 915). Models accounted for demographic confounders, attention-deficit/hyperactivity disorder, and intracranial volume. We examined two potential moderators of the relationship between GMVs and group membership: sex and clinically significant anxiety (i.e., primary vs. secondary CU traits subtype).

RESULTS

Youths in the DBDCU+ group had lower right amygdala GMV, and youths in the DBD-only group had lower bilateral amygdala GMV relative to TD youths. Youths in the DBDCU+ group had lower bilateral hippocampal GMV, and youths in the DBD-only group had lower left hippocampal GMV relative to TD youths. Youths in the DBDCU+ group evidenced lower left insula GMV relative to TD youths. Finally, youths in the DBD-only group had lower left superior frontal gyrus and lower right caudal anterior cingulate cortex GMVs relative to TD youths. There was no moderation of associations between GMV and group membership by sex.

CONCLUSIONS

Our findings implicate structural aberrations in both the amygdala and hippocampus in the etiology of DBDs, with minimal evidence for differences based on the presence or absence of CU traits.

Sex differences in antisocial and aggressive disorders that onset in childhood and persist into adulthood

As many as 10.7% of males and 7.5% of females display early-onset, stable, antisocial and aggressive behavior (ESAAB). Most research has focused on males. These individuals are diagnosed with conduct disorder in childhood and antisocial personality disorder in adulthood, and a very few, almost all males, present the syndrome of psychopathy. ESAAB includes three subgroups: (1) conduct problems and callousness; (2) conduct problems, callousness, and anxiety; and (3) conduct problems. Heritability of the first two subtypes is high. This high heritability derives, at least in part, from genes involved in regulating serotonergic functioning early in life and to genotypes that confer sensitivity to trauma. The first subtype is rare and characterized by difficulty in face emotion recognition, especially fear and sadness, and hypoarousal as indexed by both autonomic and neural measures, and by structural brain abnormalities. By contrast, those with conduct problems, callousness, and anxiety are more common. They include a greater proportion of females and show hypersensitivity to threat that triggers reactive aggression and that is reflected in both autonomic and neural functioning. In sum, fewer females than males present ESAAB, but many characteristics, autonomic and neural correlates, and etiology are similar. Importantly, however, females with ESAAB play a critical role in the intergenerational transfer of antisocial behavior. Despite higher prevalence of EASSB in males than females, few sex differences in neural abnormalities have been identified.

The Impact of Callous-Unemotional Traits and Externalizing Tendencies on Neural Responsivity to Reward and Punishment in Healthy Adolescents

Both externalizing behavior and callous-unemotional (CU) traits in youth are precursors to later criminal offending in adulthood. It is posited that disruptions in reward and punishment processes may engender problematic behavior, such that CU traits and externalizing behavior may be linked to a dominant reward response style (e.g., heightened responsivity to rewards) and deficient punishment-processing. However, prior research has generated mixed findings and work examining both the sole and joint contribution of CU traits and externalizing problems related to functional brain alterations is lacking. In this pilot functional magnetic resonance imaging study, we measured externalizing behavior and CU traits in a community sample of adolescents (n = 29) and examined their impacts on brain activity associated with anticipation and receipt of reward and punishment using the Modified Monetary Incentive Delay task. We found that CU traits were associated with greater activation of the ventral striatum (VST) during reward anticipation. However, this effect became non-significant after controlling for externalizing behavior, indicating substantial overlap between the CU and externalizing measures in explaining VST activation when anticipating reward. In addition, externalizing behavior (but not CU) was significantly negatively associated with amygdala activation during punishment receipt, even after controlling for CU traits. The present findings extend previous evidence of hyper-responsivity to reward and hypo-responsivity to punishment in relation to psychopathic traits and antisocial behavior to non-clinical, non-incarcerated youths.

Biomarkers in aggression

Aggressive behavior exerts an enormous impact on society remaining among the main causes of worldwide premature death. Effective primary interventions, relying on predictive models of aggression that show adequate sensitivity and specificity are currently lacking. One strategy to increase the accuracy and precision of prediction would be to include biological data in the predictive models. Clearly, to be included in such models, biological markers should be reliably associated with the specific trait under study (i.e., diagnostic biomarkers). Aggression, however, is phenotypically highly heterogeneous, an element that has hindered the identification of reliable biomarkers. However, current research is trying to overcome these challenges by focusing on more homogenous aggression subtypes and/or by studying large sample size of aggressive individuals. Further advance is coming by bioinformatics approaches that are allowing the integration of inter-species biological data as well as the development of predictive algorithms able to discriminate subjects on the basis of the propensity toward aggressive behavior. In this review we first present a brief summary of the available evidence on neuroimaging of aggression. We will then treat extensively the data on genetic determinants, including those from hypothesis-free genome-wide association studies (GWAS) and candidate gene studies. Transcriptomic and neurochemical biomarkers will then be reviewed, and we will dedicate a section on the role of metabolomics in aggression. Finally, we will discuss how biomarkers can inform the development of new pharmacological tools as well as increase the efficacy of preventive strategies.

Parsing neurodevelopmental features of irritability and anxiety: Replication and validation of a latent variable approach

Irritability and anxiety are two common clinical phenotypes that involve high-arousal negative affect states (anger and fear), and that frequently co-occur. Elucidating how these two forms of emotion dysregulation relate to perturbed neurodevelopment may benefit from alternate phenotyping strategies. One such strategy applies a bifactor latent variable approach that can parse shared versus unique mechanisms of these two phenotypes. Here, we aim to replicate and extend this approach and examine associations with neural structure in a large transdiagnostic sample of youth (N = 331; M = 13.57, SD = 2.69 years old; 45.92% male). FreeSurfer was used to extract cortical thickness, cortical surface area, and subcortical volume. The current findings replicated the bifactor model and demonstrate measurement invariance as a function of youth age and sex. There were no associations of youth's factor scores with cortical thickness, surface area, or subcortical volume. However, we found strong convergent and divergent validity between parent-reported irritability and anxiety factors with clinician-rated symptoms and impairment. A general negative affectivity factor was robustly associated with overall functional impairment across symptom domains. Together, these results support the utility of the bifactor model as an alternative phenotyping strategy for irritability and anxiety, which may aid in the development of targeted treatments.

Neural Profile of Callous Traits in Children: A Population-Based Neuroimaging Study

BACKGROUND

Callous traits during childhood, e.g., lack of remorse and shallow affect, are a key risk marker for antisocial behavior. Although callous traits have been found to be associated with structural and functional brain alterations, evidence to date has been almost exclusively limited to small, high-risk samples of boys. We characterized gray and white matter brain correlates of callous traits in over 2000 children from the general population.

METHODS

Data on mother-reported callous traits and brain imaging were collected at age 10 years from participants of the Generation R Study. Structural magnetic resonance imaging was used to investigate brain morphology using volumetric indices and whole-brain analyses (n = 2146); diffusion tensor imaging was used to assess global and specific white matter microstructure (n = 2059).

RESULTS

Callous traits were associated with lower global brain (e.g., total brain) volumes as well as decreased cortical surface area in frontal and temporal regions. Global mean diffusivity was negatively associated with callous traits, suggesting higher white matter microstructural integrity in children with elevated callous traits. Multiple individual tracts, including the uncinate and cingulum, contributed to this global association. Whereas no gender differences were observed for global volumetric indices, white matter associations were present only in girls.

CONCLUSIONS

This is the first study to provide a systematic characterization of the structural neural profile of callous traits in the general pediatric population. These findings extend previous work based on selected samples by demonstrating that childhood callous traits in the general population are characterized by widespread macrostructural and microstructural differences across the brain.