The "Measure of Empathy in Early Childhood": Psychometric Properties and Associations with Externalizing Problems and Callous Unemotional Traits.

Empathy is crucial to the development of socio-emotional skills in youth and empathy development is central to understanding and subtyping youth with externalizing problems. This study explored for the first time the psychometric properties of the Measure of Empathy in Early Childhood (MEEC) in a sample of 652 Italian children aged 6 to 8 years. The gender invariance of MEEC scores and their associations with other measures of empathy and prosocial behavior, and children's externalizing problems and callous-unemotional (CU) traits were also evaluated. Results indicated that with some modifications, a 5-factor structure of the Italian version of MEEC scores fitted the data and was invariant across gender. Results further supported the reliability and validity of MEEC total and subscale scores. Practical implications of these results are discussed.

Facial reactions to emotional films in young children with conduct problems and varying levels of callous-unemotional traits.

BACKGROUND: Elevated levels of callous-unemotional (CU) traits have proven useful for identifying a distinct subgroup of children whose conduct problems (CP) are early emerging, severe, persistent, and underpinned by aberrant emotional processing. The early childhood emotional experiences and expressions of CP subtypes are poorly understood, despite their importance to understanding the problematic attachments and atypical social affiliation experienced by children with elevated CU traits. The current study aimed to test for differences in facial emotional reactions to mood-inducing film clips in children with CP and varying levels of CU traits. METHOD: We compared facial emotional reactions during a developmentally appropriate mood induction task in a mixed-sex sample of clinic-referred preschool children (Mage = 3.64 years, SD = 0.63, 66.9% male) classified as CP with elevated levels of CU traits (CP + CU; n = 25) versus low CU traits (CP-only; n = 47), and typically developing children (TD; n = 28). RESULTS: Relative to TD children, children with clinical CP showed less congruent and more incongruent facial emotional expressions to sad and happy film clips, controlling for child sex, age, and ethnicity. CONCLUSIONS: Consistent with older samples, young children with CP show atypical facial emotional expressions in response to positive and negative emotional stimuli. Findings have implications for developmental models of childhood antisocial behavior and can inform the development of targeted interventions.

Sympathetic nervous system functioning during the face-to-face still-face paradigm in the first year of life.

Contemporary theories of early development and emerging child psychopathology all posit a major, if not central role for physiological responsiveness. To understand infants' potential risk for emergent psychopathology, consideration is needed to both autonomic reactivity and environmental contexts (e.g., parent-child interactions). The current study maps infants' arousal during the face-to-face still-face paradigm using skin conductance (n = 255 ethnically-diverse mother-infant dyads; 52.5% girls, mean infant age = 7.4 months; SD = 0.9 months). A novel statistical approach was designed to model the potential build-up of nonlinear counter electromotive force over the course of the task. Results showed a significant increase in infants' skin conductance between the Baseline Free-play and the Still-Face phase, and a significant decrease in skin conductance during the Reunion Play when compared to the Still-Face phase. Skin conductance during the Reunion Play phase remained significantly higher than during the Baseline Play phase; indicating that infants had not fully recovered from the mild social stressor. These results further our understanding of infant arousal during dyadic interactions, and the role of caregivers in the development of emotion regulation during infancy.

Towards Preventative Psychiatry: Concurrent and Longitudinal Predictors of Postnatal Maternal-Infant Bonding.

Maternal-infant bonding is important for children's positive development. Poor maternal-infant bonding is a risk factor for negative mother and infant outcomes. Although researchers have examined individual predictors of maternal-infant bonding, studies typically do not examine several concurrent and longitudinal predictors within the same model. This study aimed to evaluate the unique and combined predictive power of cross-sectional and longitudinal predictors of maternal-infant bonding. Participants were 372 pregnant women recruited from an Australian hospital. Data were collected from mothers at antenatal appointments (T0), following their child's birth (T1), and at a laboratory assessment when their child was 5-11-months-old (T2). Poorer bonding at T2 was predicted at T0 by younger maternal age, higher education, and higher antenatal depressive symptoms. Poorer bonding at T2 was predicted at T1 by younger maternal age, higher education, and higher postnatal depressive symptoms. Poorer bonding at T2 was predicted at T2 by younger maternal age, higher education, higher postnatal depression symptoms, higher concurrent perceived social support, and more difficult infant temperament, when controlling for child age at T2. To promote positive maternal-infant bonding, global and targeted interventions in the perinatal period may benefit from targeting maternal psychopathology, perceived lack of social support, and coping with difficult infant temperament.

Learning to like triangles: A longitudinal investigation of evaluative conditioning in infancy.

There is tentative evidence that infants can learn preferences through evaluative conditioning to socioemotional stimuli. However, the early development of evaluative conditioning and the factors that may explain infants' capacity to learn through evaluative conditioning are not well understood. Infants (N = 319; 50.2% boys) participated in a longitudinal study where an evaluative conditioning paradigm using socioemotional stimuli was conducted on two occasions (when infants were 7 and 14 months old, on average). We tested whether repeatedly pairing neutral stimuli (triangular and square shapes) with affective stimuli (angry and happy faces) affects infants' preferences for these shapes. At both timepoints, the majority of infants did not choose the shape that was paired with happy faces, indicating that, in general, learning through evaluative conditioning was not present. However, as expected, individual differences were evident such that infants who spent more time fixating on faces compared to shapes (face-preferrers) during the conditioning trials were significantly more likely than non-face-preferrers to choose the shape paired with happy faces, and this effect strengthened with increasing age.

Still connecting the dots: An investigation into infants' attentional bias to threat using an eye-tracking task.

An attentional bias toward threat has been theorized to be a normative aspect of infants' threat and safety learning, and an indicator of risk for internalizing psychopathology in older populations. To date, only four studies have examined this bias using the dot-probe task in infancy and the findings are mixed. We extended the literature by examining patterns of attention to threat in a culturally and linguistically diverse sample of infants aged 5-11 months old (N = 151) using all measures previously employed in the infant dot-probe literature. Given that an attentional bias toward threat is associated with higher risk of developing anxiety disorders later in life, we also examined how negative affect-an early correlate of later anxiety disorders-is related to attentional bias toward threat in infancy. This study was the first to use a consistent measure of negative affect across the whole sample. An eye-tracking dot-probe task was used to examine attentional bias toward threat (i.e., angry faces) relative to positive (i.e., happy faces) stimuli. Results showed that an attention bias to threat was not characteristic of infants at this age, and negative affect did not moderate the putative relationship between attention and emotional faces (angry, happy). These findings therefore suggest that attention biases to socio-emotional threat may not have emerged by 11 months old.

Callous-unemotional traits linked to earlier onset of self-reported and official delinquency in incarcerated boys.

OBJECTIVE: Research shows that youth who engage in early delinquency have higher callous-unemotional (CU) traits than youth with a later start. This study extends prior research to determine the optimal delinquency onset age cutoff for identifying youth high versus low on CU traits and the average age of delinquency onset for youth with clinically significant CU traits. HYPOTHESES: We hypothesized that youth with childhood-onset delinquency would have higher CU traits than those with adolescent-onset delinquency. We hypothesized that youth with clinically significant CU traits would have an earlier delinquency onset than youth without CU traits. We explored differences in delinquency onset between antisocial youth categorized into low-anxious primary CU variant, high-anxious secondary CU variant, and low-CU/low-anxious control groups. METHOD: Participants were 456 adjudicated, incarcerated boys (M age = 16.24 years, SD = 1.33, range 12-19; 40.4% White, 39.7% Black, 13.8% Hispanic/Latino, 6.1% other race/ethnicity) in the United States. We measured age of delinquency onset using self-report and official records. RESULTS: Boys who were 11 years old or younger when they first engaged in delinquency had higher CU traits than those who were 12 years old or older (η p 2 range = .009-.012), controlling for conduct problem severity and race/ethnicity. On average, boys with clinically significant CU traits first engaged in delinquency 1 year earlier (at 7.81 years old) than those without CU traits (η p 2 = .012). Low-anxious primary CU variants were 1 year younger at their first official charge (12.65 years old) than controls (η p 2 = .026). There were no statistically significant differences between low-anxious primary and high-anxious secondary CU variants. CONCLUSIONS: Elevated CU traits were over-represented among boys who were youngest at their first legal contact, suggesting that this may be an opportune time to identify this subgroup of youth to provide nuanced intervention to prevent later serious delinquency and criminal justice involvement. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

In the eyes of the beholder: investigating the effect of visual probing on accuracy and gaze fixations when attending to facial expressions among primary and secondary callous-unemotional variants.

Individuals with callous-unemotional (CU) traits show deficits in facial emotion recognition. According to preliminary research, this impairment may be due to attentional neglect to peoples' eyes when evaluating emotionally expressive faces. However, it is unknown whether this atypical processing pattern is unique to established variants of CU traits or modifiable with intervention. This study examined facial affect recognition and gaze patterns among individuals (N = 80; M age = 19.95, SD = 1.01 years; 50% female) with primary vs secondary CU variants. These groups were identified based on repeated measurements of conduct problems, CU traits, and anxiety assessed in adolescence and adulthood. Accuracy and number of fixations on areas of interest (forehead, eyes, and mouth) while viewing six dynamic emotions were assessed. A visual probe was used to direct attention to various parts of the face. Individuals with primary and secondary CU traits were less accurate than controls in recognizing facial expressions across all emotions. Those identified in the low-anxious primary-CU group showed reduced overall fixations to fearful and painful facial expressions compared to those in the high-anxious secondary-CU group. This difference was not specific to a region of the face (i.e. eyes or mouth). Findings point to the importance of investigating both accuracy and eye gaze fixations, since individuals in the primary and secondary groups were only differentiated in the way they attended to specific facial expression. These findings have implications for differentiated interventions focused on improving facial emotion recognition with regard to attending and correctly identifying emotions.

ParentWorks: Evaluation of an Online, Father-Inclusive, Universal Parenting Intervention to Reduce Child Conduct Problems.

Evidence-based parenting interventions are effective in reducing conduct problems, yet these interventions have limited reach, and few involve the participation of fathers. This paper describes the outcomes of an open trial of ParentWorks, a universal, online, father-inclusive parenting intervention aiming to decrease childhood behavioural problems and promote positive parenting in mothers and fathers. A total of 388 families (456 individual parents; 36.6% fathers) were included in the study. Mixed model analyses showed significant decreases in child emotional/behavioural problems, dysfunctional parenting, interparental conflict, and parental mental health problems. The baseline severity of child behavioural problems significantly moderated the effects on child outcomes so that children with higher levels of problems benefitted more from the program. Participation of both caregivers in two-parent families, as well as parent sex, did not significantly affect the program outcomes. Results provide initial empirical support for the universal, self-directed, online parenting intervention, in addressing both child behavioural problems and parenting outcomes. Trial registration: ACTRN12616001223426, registered 05/09/2016.

Parent-Child Interaction Therapy Adapted for Preschoolers with Callous-Unemotional Traits: An Open Trial Pilot Study.

Children with co-occurring conduct problems and callous-unemotional (CU) traits show a distinct pattern of early starting, chronic, and aggressive antisocial behaviors that are resistant to traditional parent-training interventions. The aim of this study was to examine in an open trial the acceptability and initial outcomes of a novel adaptation of Parent-Child Interaction Therapy, called PCIT-CU, designed to target 3 distinct deficits of children with CU traits. Twenty-three Australian families with a 3- to 6-year-old (M age = 4.5 years, SD = .92) child with clinically significant conduct problems and CU traits participated in the 21-week intervention and 5 assessments measuring child conduct problems, CU traits, and empathy at a university-based research clinic. Treatment retention was high (74%), and parents reported a high level of satisfaction with the program. Results of linear mixed models indicated that the intervention produced decreases in child conduct problems and CU traits, and increases in empathy, with "medium" to "huge" effect sizes (ds = 0.7-2.0) that maintained at a 3-month follow-up. By 3 months posttreatment, 75% of treatment completers no longer showed clinically significant conduct problems relative to 25% of dropouts. Findings provide preliminary support for using the targeted PCIT-CU adaptation to treat young children with conduct problems and co-occurring CU traits.

Keeping Parents Involved: Predicting Attrition in a Self-Directed, Online Program for Childhood Conduct Problems.

Positive parenting programs have a strong evidence base for improving parent-child relationships, strengthening families, and reducing childhood behavior disturbances. Their reach is less than optimal however, with only a minority of families in need of help participating. Father involvement is particularly low. Online, self-directed programs have the potential to improve participation rates. This article examines risk factors for dropout/attrition from a free, evidence-based, self-directed, father-inclusive parenting program, Parentworks, which was made available across Australia. Parents (N = 2,967) enrolled in the program and completed preintervention questionnaires. There was a steady and consistent loss of participants through the sequence of core program modules, until a final sample of 218 completed the postintervention questionnaire. A range of demographic and parent and child variables were tested as predictors of 3 subgroups: nonstarters, partial completers, and full completers. Nonstarters (n = 1,625) tended to have older children with fewer behavioral problems and report higher psychopathology and dysfunctional parenting than those who partially (n = 1,124) or fully completed. Contrary to findings from face-to-face research, single parents had the highest completion rates. Coparticipation of partners and interparental conflict had no impact on completion rates. Fathers participated at relatively high levels. Results show that parents with the greatest need tend to engage with online programs, and online programs may be particularly useful for fathers, single parents, and those in conflicted relationships. Directions for future program design and research are discussed.

Evaluation of 'The Father Effect' Media Campaign to Increase Awareness of, and Participation in, an Online Father-Inclusive Parenting Program.

There is substantial evidence that parenting programs are effective in improving parenting and child mental health outcomes. While there is increasing focus on delivering parenting interventions online to increase their reach and dissemination, fathers are underrepresented in all formats of parenting programs. However, research suggests that father participation is important for intervention effectiveness. This study evaluated the effectiveness of a media campaign for increasing awareness of, and participation in, an online father-inclusive parenting program called 'ParentWorks'. An 8-week campaign was conducted in Australia via social media channels, digital display advertising, digital television, and radio. To assess the impact of the campaign, data were obtained from caregivers registering for ParentWorks during the campaign period (n = 848) and an 8-week comparison period that occurred 3 months later (n = 254). Additionally, a nationally representative sample of 2021 caregivers of children aged 2-16 years completed an online survey. Survey questions asked about exposure to the campaign, registration for participation in ParentWorks, and knowledge of the importance of father participation in parenting programs. Three times as many caregivers registered during the 8-week media campaign compared to the comparison period, and a significantly greater proportion of male caregivers registered in the campaign versus the comparison period. The online survey found that 11% of caregivers reported exposure to the campaign, and significantly more fathers than mothers reported exposure. Results showed that those who were exposed to the campaign were significantly more likely to endorse the importance of father participation in parenting programs, than those not exposed to the campaign. The findings indicate that media campaigns appear to be an effective method of increasing awareness of online parenting programs and enhancing rates of father involvement.

Are impairments in emotion recognition a core feature of callous-unemotional traits? Testing the primary versus secondary variants model in children.

The role of environmental adversity in the development of high callous-unemotional (CU) traits in children is controversial. Evidence speaks to the traits being largely independent of adversity; however, recent data shows that those with high CU traits and high adversity and/or high anxiety might differ in important ways from those with no such history. We tested this using emotion recognition (ER) skills. We tested whether maltreatment history and anxiety levels moderated the relationship between level of CU traits and ER skills in N = 364 children with behavioral problems who were 3 to 16 years old. As hypothesised, in the full sample, the relationship between CU traits and ER differed according to maltreatment history, such that CU traits were associated with poorer recognition for those with zero or negligible history of maltreatment. This moderation of the CU-ER relationship by maltreatment was inconsistent across subgroups, however, and for the cohort utilizing youth self-report of maltreatment, high CU traits were associated with poor ER in those with lower anxiety levels. Maltreatment history and/or anxiety levels can identify different emotional impairments associated with high CU traits, and the impairments might be characteristic of "primary" high CU traits defined as occurring independently of maltreatment and/or high anxiety.

Affective startle potentiation differentiates primary and secondary variants of juvenile psychopathy.

Individuals with psychopathic traits show an attenuated emotional response to aversive stimuli. However, recent evidence suggests heterogeneity in emotional reactivity among individuals with psychopathic or callous-unemotional (CU) traits in the identification of primary and secondary subtypes, or variants. We hypothesized that primary CU variants will respond with blunted affect to negatively valenced stimuli, whereas individuals with a history of childhood maltreatment, fitting with theoretical conceptualizations of secondary psychopathy, will display heightened emotional reactivity. To test this hypothesis, we examined fear-potentiated startle between CU variants while viewing aversive, pleasant, and neutral scenes. Two hundred thirty-eight incarcerated adolescent (M age = 16.8 years, SD = 1.11 years) boys completed a picture-startle paradigm and self-report questionnaires assessing CU traits, aggressive behavior, and maltreatment. Latent profile analysis of CU trait, aggression, and maltreatment scores identified four classes: primary psychopathy variants (high CU traits, high aggression, low maltreatment; n = 46), secondary psychopathy variants (high CU traits, high aggression, high maltreatment; n = 42), and two nonpsychopathic groups differentiated on maltreatment experience (n = 148). Primary CU variants displayed reduced startle potentiation to aversive images relative to control, maltreated, and also secondary variants that exhibited greater startle modulation. Findings add to a rapidly growing body of literature supporting the possibility of multiple developmental pathways to psychopathic traits (i.e., equifinality), and extend it by finding support for divergent potential biomarkers between primary and secondary CU variants.

Optimising child outcomes from parenting interventions: fathers' experiences, preferences and barriers to participation.

BACKGROUND: Early childhood interventions can have both immediate and long-term positive effects on cognitive, behavioural, health and education outcomes. Fathers are underrepresented in interventions focusing on the well-being of children. However, father participation may be critical for intervention effectiveness, especially for parenting interventions for child externalising problems. To date, there has been very little research conducted to understand the low rates of father participation and to facilitate the development of interventions to meet the needs of fathers. This study examined fathers' experiences of, and preferences for, parenting interventions as well as perceptions of barriers to participation. It also examined how these factors were associated with child externalising behaviour problems, and explored the predictors of participation in parenting interventions. METHODS: A community sample of 1001 fathers of children aged 2-16 years completed an online survey about experiences with parenting interventions, perceived barriers to participation, the importance of different factors in their decision to attend, and preferred content and delivery methods. They also completed ratings of their child's behaviour using the Strengths and Difficulties Questionnaire. RESULTS: Overall, 15% of fathers had participated in a parenting intervention or treatment for child behaviour, with significantly higher rates of participation for fathers of children with high versus low levels of externalising problems. Fathers rated understanding what is involved in the program and knowing that the facilitator is trained as the two most important factors in their decision to participate. There were several barriers to participation that fathers of children with high-level externalising problems were more likely to endorse, across practical barriers and help-seeking attitudes, compared to fathers of children with low-level externalising problems. Almost two-thirds of fathers of children with high-level externalising behaviour had not participated in a parenting intervention or treatment. The only significant predictors of intervention participation were severity of child externalising behaviour problems and child age. CONCLUSIONS: The findings have important implications for services seeking to increase father engagement and highlight a number of strategies to enhance the promotion and delivery of parenting interventions to fathers. These strategies include more public health messaging about parenting programs and the importance of father participation.

Neuroendocrine factors distinguish juvenile psychopathy variants.

The characteristic pattern of emotional hypo-reactivity observed in primary psychopathy is not evident in secondary psychopathy, which is thought to originate from childhood adversity and co-occurring anxiety. The main aim of this study was to test whether salivary afternoon cortisol, Dehydroepiandrosterone (DHEA), and cortisol-to-DHEA concentrations, which at high levels indicate risk for chronic stress and poor mental health, distinguished secondary from primary variants of callous-unemotional (CU) traits-the affective component of psychopathy. This aim was achieved by first identifying psychopathy variants using latent profile analysis of CU, anxiety, and aggression scores among 232 incarcerated adolescent boys (M age = 16.75). Based on a subset with neuroendocrine data (n = 201), aggressive secondary CU variants had lower afternoon DHEA concentrations and higher cortisol-to-DHEA ratios and comorbid psychopathology compared with all other groups. In contrast, two primary CU variants (aggressive and non-aggressive types) emerged with profiles characterized by low to average psychopathology and high DHEA levels. Findings contribute to a growing literature base suggesting that biomarkers may distinguish youth on separable developmental pathways to psychopathy.

Factors differentiating callous-unemotional children with and without conduct problems.

BACKGROUND: Callous-unemotional (CU) traits are a risk factor for a severe, aggressive, and persistent pattern of conduct problems (CP). This study investigated characteristics that might differentiate children with elevated CU traits with and without CP in an effort to identify factors that may reduce the risk for CP in children with limited prosocial emotions. METHODS: Utilizing a sample of 1,366 children from Cyprus, five groups were identified for further study based on latent profile analysis: low-risk (67.2%), high-CP/low-CU (7.9%), high-CU (9.4%), moderate-CP/CU (8.4%), and high-CP/CU (7.2%). The identified groups were compared on behavioral and social measures. RESULTS: There were significant main effects of group for: impulsivity and executive functioning; parenting; and connectedness to school. The high-CU group had significantly lower hyperactivity-impulsivity and executive functioning deficits, significantly higher self-regulation, and their mothers reported more maternal involvement and positive parenting than those in the high-CP/CU group. Also, the high-CU group showed more school connectedness than those in the high-CP/CU group. CONCLUSIONS: These findings highlight several factors in the child and in his or her social environment that are associated with CU traits in the absence of serious CP and that may suggest targets for intervention for youth who may lack prosocial emotions.

Do neurocognitive deficits in decision making differentiate conduct disorder subtypes?

The present study aimed to test whether neurocognitive deficits involved in decision making underlie subtypes of conduct-disorder (CD) differentiated on the basis of callous-unemotional (CU) traits. Eighty-five participants (M age = 10.94 years) were selected from a sample of 1200 children based on repeated assessment of CD and CU traits. Participants completed a multi-method battery of well-validated measures of risky decision making and associated constructs of selective attention and future orientation (Stroop, Stoplight, and Delay-Discounting Tasks). Findings indicated that impaired decision making, selective attention, and future orientation contribute to the antisocial presentations displayed by children with CD, irrespective of level of CU traits. Youth high on CU traits without CD showed less risky decision making, as indicated by their performance on the Stoplight laboratory task, than those high on both CD and CU traits, suggesting a potential protective factor against the development of antisocial behavior.

Using self-reported callous-unemotional traits to cross-nationally assess the DSM-5 'With Limited Prosocial Emotions' specifier.

BACKGROUND: The presence of callous-unemotional (CU) traits designates an important subgroup of antisocial youth at risk for severe, persistent, and impairing conduct problems. As a result, the fifth revision of the Diagnostic and Statistical Manual includes a specifier for youth meeting diagnostic criteria for Conduct Disorder who show elevated CU traits. The current study evaluated the DSM-5 criteria using Item Response Theory (IRT) analyses and evaluated two methods for using a self-report measure of CU traits to make this diagnosis. METHODS: The sample included 2257 adolescent (M age = 15.64, SD = 1.69 years) boys (53%) and girls (47%) from community and incarcerated settings in the United States and the European countries of Belgium, Germany, and Cyprus. RESULTS: IRT analyses suggested that four- or eight-item sets from the self-report measure (comparable to the symptoms used by the DSM-5 specifier) provided good model fit, suggesting that they assess a single underlying CU construct. Further, the most stringent method of scoring the self-report scale (i.e. taking only the most extreme responses) to approximate symptom presence provided the best discrimination in IRT analyses, showed reasonable prevalence rates of the specifier, and designated community adolescents who were highly antisocial, whereas the less stringent method best discriminated detained youth. CONCLUSIONS: Refined self-report scales developed on the basis of IRT findings provided good assessments of most of the symptoms used in the DSM-5 criteria. These scales may be used as one component of a multimethod assessment of the 'With Limited Prosocial Emotions' specifier for Conduct Disorder.

Profiles of the forms and functions of self-reported aggression in three adolescent samples.

In the current study, we addressed several issues related to the forms (physical and relational) and functions (reactive and proactive) of aggression in community (n = 307), voluntary residential (n = 1,917), and involuntarily detained (n = 659) adolescents (ages 11-19 years). Across samples, boys self-reported more physical aggression and girls reported more relational aggression, with the exception of higher levels of both forms of aggression in detained girls. Further, few boys showed high rates of relational aggression without also showing high rates of physical aggression. In contrast, it was not uncommon for girls to show high rates of relational aggression alone, and these girls tended to also have high levels of problem behavior (e.g., delinquency) and mental health problems (e.g., emotional dysregulation and callous-unemotional traits). Finally, for physical aggression in both boys and girls, and for relational aggression in girls, there was a clear pattern of aggressive behavior that emerged from cluster analyses across samples. Two aggression clusters emerged, with one group showing moderately high reactive aggression and a second group showing both high reactive and high proactive aggression (combined group). On measures of severity (e.g., self-reported delinquency and arrests) and etiologically important variables (e.g., emotional regulation and callous-unemotional traits), the reactive aggression group was more severe than a nonaggressive cluster but less severe than the combined aggressive cluster.