Background: Adverse childhood experiences (ACEs) are presumed to influence internalizing and externalizing behaviors that can significantly debilitate long-term biopsychological development in individuals. Psychological resilience has been shown to effectively mediate the relationship between ACEs and negative health outcomes since individuals with low levels of resilience may have difficulty with bouncing back from toxic exposure to ACEs. Thus, the present systematic review and meta-analysis was aimed toward synthesizing current knowledge of the relationship between ACEs and psychological resilience in youths. Methods: A combination of key words relevant to the present study was searched on the PubMed, EMBASE, Scopus, Cochrane, and Google Scholar databases. The results were restricted to English publications and human studies, with subjects ranging between the age of 0 to 35 years. Effect-size measures inclusive of pooled correlation coefficients for correlation analyses and pooled odds ratios for regression analyses, respectively, were calculated using random-effect models to determine the relationship between ACEs and psychological resilience. Results: The searches identified 85 potentially relevant studies. Among them, 76 were excluded due to limited access, irrelevant data, and the fact that the variables of interest were not explicitly measured or disclosed, leaving a final total of nine studies considered valid for the meta-analysis. Findings from correlational meta-analysis (n = 6) revealed a significantly negative association between ACEs and resilience (β = −0.120 [−0.196, −0.043]). The meta-analysis of the studies (n = 3) reporting dichotomous outcomes (ACE ≥ 1 vs. no ACE) indicated that subjects who experienced an ACE were 63% less likely to display high resilience, in comparison to subjects without such experiences. Conclusion: Our results support a negative association between ACEs and psychological resilience and highlight the multiple dimensions that constitute resilience in an ACE-exposure context. These findings may be particularly useful to policy makers and healthcare institutions in terms of helping them devise effective medical interventions and community outreach programs intended to develop resilience in youths, thus reducing health-risk behaviors and negative health outcomes.

Although prefrontal brain impairments are one of the best-replicated brain imaging findings in relation to aggression, little is known about the causal role of this brain region. This study tests whether stimulating the dorsolateral prefrontal cortex (DLPFC) using transcranial direct current stimulation (tDCS) reduces the likelihood of engaging in aggressive acts, and the mechanism underlying this relationship. In a double-blind, stratified, placebo-controlled, randomized trial, 81 human adults (36 males, 45 females) were randomly assigned to an active (N = 39) or placebo (N = 42) condition, and followed up one day after the experiment session. Intentions to commit aggressive acts and behavioral aggression were assessed using hypothetical vignettes and a behavioral task, respectively. The secondary outcome was the perception of the moral wrongfulness of the aggressive acts. Participants who received anodal stimulation reported being less likely to commit physical and sexual assault (p < .01), and judged aggressive acts as more morally wrongful (p < .05) compared to the sham controls. 31% of the total effect of tDCS on intentions to commit aggression was accounted for by perceptions of greater moral wrongfulness regarding the aggressive acts. Results provide experimental evidence that increasing activity in the prefrontal cortex can reduce intentions to commit aggression and enhance perceptions of moral judgment. Findings shed light on the biological underpinnings of aggression and theoretically have the potential to inform future interventions for aggression and violence. Trial Registration ClinicalTrials.gov identifier: NCT02427672 SIGNIFICANCE STATEMENT Aggressive behaviors pose significant public health risks. Understanding the etiology of aggression is paramount to violence reduction. Investigations of the neural basis of aggression have largely supported correlational, rather than causal interpretations, and the mediating processes underlying the prefrontal-aggression relationship remain to be well-elucidated. Through a double-blind, stratified, placebo-controlled, randomized trial, this study tested whether upregulation of the prefrontal cortex reduces the likelihood of engaging in aggression. Results provide experimental evidence that increasing prefrontal cortical activity can reduce intent to commit aggressive acts. They also shed light on moral judgment as one mechanism that may link prefrontal deficits to aggression and in theory, have the potential to inform future approaches towards reducing aggression.

Objectives: Tests the hypothesis that the social adversity-antisocial behavior relationship is partly mediated by a biological mechanism, low heart rate. Method: 18 indicators of social adversity and heart rate measured at rest and in anticipation of a speech stressor were assessed alongside nine measures of antisocial behavior including delinquency (Youth Self-Report [YSR] and Child Behavior Checklist [CBCL]), conduct disorder (Conduct Disorder and Oppositional Defiant Disorder Questionnaire), and child psychopathy (Antisocial Process Screening Device [APSD]) in a community sample of 388 children aged 11 to 12 years. PROCESS was used to test mediation models. Results: Low heart rate was a partial mediator of the adversity-antisocial behavior relationship, explaining 20.35 percent and 15.40 percent of the effect of social adversity on delinquency and overall antisocial behavior, respectively. Conclusions: Findings are, to the authors’ knowledge, one of the first to establish any biological risk factor as a mediator of the social adversity-antisocial behavior relationship and suggest that social processes alter autonomic functioning in a way to predispose to antisocial behavior. While not definitive, results give rise to a social neurocriminology theory that argues that the social environment influences biological risk factors in a way to predispose to antisocial and criminal behavior.

Background: While studies suggest that nutritional supplementation may reduce aggressive behavior in children, few have examined their effects on specific forms of aggression. This study tests the primary hypothesis that omega-3 (ω-3), both alone and in conjunction with social skills training, will have particular post-treatment efficacy for reducing childhood reactive aggression relative to baseline.Methods: In this randomized, double-blind, stratified, placebo-controlled, factorial trial, a clinical sample of 282 children with externalizing behavior aged 7–16 years was randomized intoω-3 only, social skills only,ω-3 + social skills, and placebo control groups. Treatment duration was 6 months. The primary outcome measure was reactive aggression collected at 0, 3, 6, 9, and 12 months, with antisocial behavior as a secondary outcome.Results: Children in theω-3-only group showed a short-term reduction (at 3 and 6 months) in self-report reactive aggression, and also a short-term reduction in overall antisocial behavior. Sensitivity analyses and a robustness check replicated significant interaction effects. Effect sizes (d) were small, ranging from 0.17 to 0.31.Conclusions: Findings provide some initial support for the efficacy ofω-3 in reducing reactive aggression over and above standard care (medication and parent training), but yield only preliminary and limited support for the efficacy ofω-3 in reducing overall externalizing behavior in children. Future studies could test further whetherω-3 shows promise in reducing more reactive, impulsive forms of aggression.