Externalizing Behavior in at-Risk Preadolescents: Relationships among Effortful Control, Affective Experiences, and Autonomic Psychophysiology

Increased cardiac vagal tone in childhood-only, adolescent-only, and persistently antisocial teenagers: the mediating role of low heart rate

BACKGROUND

Cardiac vagal tone is an indicator of parasympathetic nervous system functioning, and there is increasing interest in its relation to antisocial behavior. It is unclear however whether antisocial individuals are characterized by increased or decreased vagal tone, and whether increased vagal tone is the source of the low heart rate frequently reported in antisocial populations.

METHODS

Participants consisted of four groups of community-dwelling adolescent boys aged 15.7 years: (1) controls, (2) childhood-only antisocial, (3) adolescent-only antisocial, and (4) persistently antisocial. Heart rate and vagal tone were assessed in three different conditions: rest, cognitive stressor, and social stressor.

RESULTS

All three antisocial groups had both lower resting heart rates and increased vagal tone compared to the low antisocial controls across all three conditions. Low heart rate partially mediated the relationship between vagal tone and antisocial behavior.

CONCLUSIONS

Results indicate that increased vagal tone and reduced heart rate are relatively broad risk factors for different developmental forms of antisocial behavior. Findings are the first to implicate vagal tone as an explanatory factor in understanding heart rate - antisocial behavior relationships. Future experimental work using non-invasive vagus nerve stimulation or heart rate variability biofeedback is needed to more systematically evaluate this conclusion.

Autonomic nervous system reactivity to emotion and childhood trajectories of relational and physical aggression

This study investigated the role of autonomic nervous system (ANS) coordination in response to emotion in girls' and boys' development of relational (e.g., ignoring, excluding) and physical (e.g., hitting, kicking) aggression. Caregivers reported on children's relational and physical aggression at ages 6, 7, 8, and 10 years (N = 232, 50.4% girls, 46.6% Latinx). Sympathetic nervous system (assessed via pre-ejection period) and parasympathetic nervous system (assessed via respiratory sinus arrhythmia) reactivity were measured in response to video clips depicting fear, happiness, and sadness at age 7. Growth curve models indicated that ANS reactivity to sadness, but not to fear or happiness, was related to trajectories of relational aggression. In contrast, ANS reactivity to all three emotions was associated with trajectories of physical aggression. Effects differed across genders, indicating that distinct patterns of ANS reactivity to emotion may be involved in girls' and boys' development of aggression. Overall, these findings contribute to a growing literature documenting the role of ANS reactivity to emotion in aggressive behavior. Moreover, this study considers ANS reactivity to specific emotions, as related to both relational and physical aggression, and as differentially expressed among girls versus boys.

High resting heart rate protects against the intergenerational transmission of antisocial behavior: a birth cohort study

Although social influences have been identified that protect against the intergenerational transmission of antisocial behavior, there has been no prior research on biological protective factors. This study examines whether high resting heart rate may be one such factor. Resting heart rate was measured in 405 children of parents from a birth cohort, together with antisocial behavior in both the parent and the child. Children who were not antisocial, but had a parent high on antisocial behavior, had higher resting heart rates than all three other parent-child antisocial behavior groupings. Results withstood control for age, gender, ethnicity, body mass index, and psychosocial adversity. Robustness checks confirmed these results. Findings are the first to identify a biological protective factor against the intergenerational transmission of childhood antisocial behavior.

Mindful Coping Power Effects on Children's Autonomic Nervous System Functioning and Long-Term Behavioral Outcomes

Mindful Coping Power (MCP) was developed to enhance the effects of the Coping Power (CP) preventive intervention on children's reactive aggression by integrating mindfulness training into CP. In prior pre-post analyses in a randomized trial of 102 children, MCP improved children's self-reported anger modulation, self-regulation, and embodied awareness relative to CP but had fewer comparative effects on parent- and teacher-reported observable behavioral outcomes, including reactive aggression. It was hypothesized that MCP-produced improvements in children's internal awareness and self-regulation, if maintained or strengthened over time with ongoing mindfulness practice, would yield improvements in children's observable prosocial and reactive aggressive behavior at later time points. To appraise this hypothesis, the current study examined teacher-reported child behavioral outcomes at a one-year follow-up. In the current subsample of 80 children with one-year follow-up data, MCP produced a significant improvement in children's social skills and a statistical trend for a reduction in reactive aggression compared with CP. Further, MCP produced improvements in children's autonomic nervous system functioning compared with CP from pre- to post-intervention, with a significant effect on children's skin conductance reactivity during an arousal task. Mediation analyses found that MCP-produced improvements in inhibitory control at post-intervention mediated program effects on reactive aggression at the one-year follow-up. Within-person analyses with the full sample (MCP and CP) found that improvements in respiratory sinus arrhythmia reactivity were associated with improvements in reactive aggression at the one-year follow-up. Together, these findings indicate that MCP is an important new preventive tool to improve embodied awareness, self-regulation, stress physiology, and observable long-term behavioral outcomes in at-risk youth. Further, children's inhibitory control and autonomic nervous system functioning emerged as key targets for preventive intervention.

Effects of Autonomic Nervous System Functioning and Tornado Exposure on Long-Term Outcomes of Aggressive Children

This study examined whether pre-disaster indicators of sympathetic and parasympathetic activity moderated the relation between degree of disaster exposure from an EF-4 tornado and changes in the externalizing and internalizing behavior problems of children at-risk for aggression. Participants included 188 children in 4th-6th grades (65% male; 78% African American; ages 9-13) and their parents from predominantly low-income households who were participating in a prevention study when the tornado occurred in 2011. Fourth-grade children who exhibited elevated levels of aggressive behavior were recruited in three annual cohorts. Parent-rated externalizing and internalizing problems were assessed prior to the tornado (Wave 1; W1), and at 4-12 months (W2), 16-24 months (W3), 42-28 months (W4) and 56-60 months (W5) post-tornado. Children's pre-tornado Skin Conductance Level (SCL) reactivity and Respiratory Sinus Arrhythmia (RSA) withdrawal were assessed at W1 using SCL and RSA measured during resting baseline and during the first 5 min of the Iowa Gambling Task (IGT). Children and parents reported their exposure to tornado-related trauma and disruptions at Wave 3. Children displayed less reduction in externalizing problems if there had been higher child- or parent-reported tornado exposure and less RSA withdrawal, or if they had lower parent-reported TORTE and less SCL reactivity or lower SCL baseline. Highlighting the importance of children's pre-disaster arousal, higher levels of disaster exposure negatively affected children's level of improvement in externalizing problems when children had less vagal withdrawal, and when tornado exposure disrupted the protective effects of higher SCL reactivity and higher SCL baseline.

Group versus individual format of intervention for aggressive children: Moderators and predictors of outcomes through 4 years after intervention

This study originated in collaboration with Thomas Dishion because of concerns that a group format for aggressive children might dampen the effects of cognitive-behavioral intervention. Three hundred sixty aggressive preadolescent children were screened through teacher and parent ratings. Schools were randomized to receive either an individual or a group format of the child component of the same evidence-based program. The results indicate that there is variability in how group-based cognitive-behavioral intervention can affect aggressive children through a long 4-year follow-up after the end of the intervention. Aggressive children who have higher skin conductance reactivity (potentially an indicator of poorer emotion regulation) and who have a variant of the oxytocin receptor gene that may be associated with being hyperinvolved in social bonding have better outcomes in their teacher-rated externalizing behavior outcomes over time if they were seen individually rather than in groups. Analyses also indicated that higher levels of the group leaders' clinical skills predicted reduced externalizing behavior problems. Implications for group versus individual format of cognitive-behavioral interventions for aggressive children, and for intensive training for group therapists, informed by these results, are discussed.

Autonomic functioning in reactive versus proactive aggression: The influential role of inconsistent parenting

Research has consistently supported autonomic nervous system (ANS) functioning as a predictor of aggressive behavior in youth. Several studies have further examined how the functioning of the sympathetic (SNS) and parasympathetic (PNS) branches of the ANS interact with environmental factors to predict behavioral outcomes. One factor that has yet to be studied in this context however, is parenting practices. Given that many interventions for externalizing behavior target parenting practices, such as increasing consistent discipline, it may be particularly important to assess whether parenting practices interact with SNS and PNS functioning in the child to influence risk for aggressive behavior. Therefore, the current study addressed this question by examining inconsistent discipline as a moderator of the relationship between baseline SNS versus PNS activity and reactive versus proactive aggression. Data were collected from a sample of fourth graders identified as at-risk for aggression (N = 188). Results indicated that baseline SNS activity was positively related to proactive aggression under high levels of inconsistent discipline, but negatively related to proactive aggression under very low levels of inconsistent discipline. Baseline PNS activity was negatively associated with reactive aggression under low levels of inconsistent discipline. No main effects were found for SNS or PNS functioning and either form of aggression, emphasizing the importance of taking a biosocial approach to examining the predictors of aggressive behavior in at-risk youth. Results from this study help to better understand the circumstances under which children are most likely to exhibit reactive versus proactive aggression, better informing targeted prevention and treatment.