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Although a low resting heart rate is considered the best-replicated biological correlate of antisocial behavior, the mechanism underlying this relationship remains largely unknown. Sensation-seeking and fearlessness theories have been proposed to explain this relationship, although little empirical research has been conducted to test these theories. This study addressed this limitation by examining the relationship between heart rate and antisocial behavior in a community sample of 335 adolescent boys. Heart rate was measured during a series of cognitive, stress, and rest tasks. Participants also completed self-report measures of state fear, impulsive sensation seeking, and both aggressive and nonaggressive forms of antisocial behavior. As expected, increased levels of aggression and nonviolent delinquency were associated with a low heart rate. Impulsive sensation seeking, but not fearlessness, significantly mediated the association between heart rate and aggression. This study is the first to show that impulsive sensation seeking partly underlies the relationship between aggression and heart rate, and it is one of the few to examine the mechanism of action linking heart rate to antisocial behavior. Findings at a theoretical level highlight the role of impulsive sensation seeking in understanding antisocial behavior and at an intervention level suggest it as a potential target for behavioral change.Autonomic nervous system activity has long been examined in relation to psychopathy, aggression, and antisocial behavior (e.g., Davies and Maliphant, 1971;Hare, 1968). Psychophysiological indices of autonomic activity, which are noninvasive to record and capture nearly immediate physiological changes in response to external stimuli, include skin conductance, heart rate, and skin-potential response. Of these measures, a low resting heart rate is considered the best-replicated biological correlate of antisocial behavior in children and adolescents (Lorber, 2004;Ortiz and Raine, 2004). One meta-analysis *

Although low resting heart rate has been viewed as a well-replicated biological correlate of child and adolescent antisocial behavior, little is known about how it interacts with psychosocial adversity in predisposing to both reactive-proactive aggression and psychopathy, and whether this relationship generalizes to an East Asian population. This study tests the hypothesis that low resting heart rate will be associated with aggression and psychopathic traits, and that heart rate will interact with adversity in predisposing to these antisocial traits. Resting heart rate was assessed in 334 Hong Kong male and female schoolchildren aged 11-17 years. A social adversity index was calculated from a psychosocial interview of the parent, while parents assessed their children on the Reactive-Proactive Aggression Questionnaire and the Antisocial Personality Screening Device. Low resting heart rate was significantly associated with higher proactive aggression, impulsive features of psychopathy, and total child psychopathy. Low resting heart rate interacted with high psychosocial adversity in explaining higher reactive (but not proactive) aggression, as well as impulsive psychopathy. These findings provide support for a biosocial perspective of reactive aggression and impulsive psychopathy, and document low resting heart rate as a robust correlate of both childhood impulsive psychopathic behavior and proactive aggression. To our knowledge, this study is the first to document low resting heart rate as a correlate of child psychopathy and the second to establish low heart rate as a risk factor of antisocial behavior in an East Asian population. The findings provide further evidence for both low resting heart rate as a potential biomarker for childhood psychopathic and aggressive behavior, and also a biosocial perspective on childhood antisocial behavior.

Background While limited evidence suggests that omega-3 supplementation may reduceantisocial behavior in children, studies have not reported on post-treatment follow-up and most treatment periods have been of short duration. This study tests the hypothesis that omega-3 supplementation over six months will reduce behavior problems in children both at the end of treatment and at six months post-treatment. Methods In this randomized, double-blind, placebo-controlled, stratified, parallel group trial, a community sample of 8-16 year old children were randomized into a treatment group (N = 100) and a placebo-control group (N = 100). The supplementation consisted of a fruit drink containing 1 gram/day of omega-3 or a placebo consisting of the same fruit drink without omega-3. Participants, care-givers, and research assistants were blinded to group assignment. The primary outcome measures of externalizing and internalizing behavior problems were reported by both caregivers and their children in a laboratory setting at 0 months (baseline), 6 months (end of treatment) and 12 months (6 months post-treatment), together with the secondary outcome measures of parental antisocial behavior. Data were analyzed on an intention-to-treat basis including all participants. Results Significant group × time interactions were observed with the treatment group showing long-term improvements in child behavior problems. The average post-treatment effect size was d = -.59. Effects were documented for parent-reports, but with theexception of proactive and reactive aggression,child-report data were non-significant.Parents whose children took omega-3showed significant post-treatment reductions in their own antisocial and aggressive behavior.Thisimprovementin caregiver behavior partly mediated the improvements observed in child behavior. Conclusions Findings provide initialevidence that omega-3 supplementation can produce sustained reductions in externalizing andinternalizing behavior problems. Results are the first to report improvements in caregiver behavior, and to establishthis improvement as a part-mechanism for the efficacy of omega-3.

Findings provide some limited support for the efficacy of omega-3, vitamin, and mineral supplementation in reducing aggressive behavior in children, and represent the first evaluation of nutritional supplements in conjunction with CBT.