Jill Portnoy

Reduction in behavior problems with omega‐3 supplementation in children aged 8–16 years: a randomized, double‐blind, placebo‐controlled, stratified, parallel‐group trial

BACKGROUND While limited evidence suggests that omega-3 supplementation may reduce antisocial behavior in children, studies have not reported on posttreatment follow-up and most treatment periods have been of short duration. This study tests the hypothesis that omega-3 supplementation over 6 months will reduce behavior problems in children both at the end of treatment and at 6 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 g/day of omega-3 or a placebo consisting of the same fruit drink without omega-3. Participants, caregivers, 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. TRIAL REGISTRATION ClinicalTrials.gov: http://clinicaltrials.gov/ct2/show/NCT02016079?term=mauritius&rank=2 RESULTS: Significant group × time interactions were observed with the treatment group showing long-term improvements in child behavior problems. The average posttreatment effect size was d = -.59. Effects were documented for parent reports, but with the exception of proactive and reactive aggression, child-report data were nonsignificant. Parents whose children took omega-3 showed significant posttreatment reductions in their own antisocial and aggressive behavior. This improvement in caregiver behavior partly mediated the improvements observed in child behavior. CONCLUSIONS Findings provide initial evidence that omega-3 supplementation can produce sustained reductions in externalizing and internalizing behavior problems. Results are the first to report improvements in caregiver behavior, and to establish this improvement as a part-mechanism for the efficacy of omega-3.

HEART RATE AND ANTISOCIAL BEHAVIOR: THE MEDIATING ROLE OF IMPULSIVE SENSATION SEEKING

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. Language: en

Low heart rate as a risk factor for child and adolescent proactive aggressive and impulsive psychopathic behavior

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.

The Mediating Role of Heart Rate on the Social Adversity-Antisocial Behavior Relationship A Social Neurocriminology Perspective

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.

Association between a marker for prenatal testosterone exposure and externalizing behavior problems in children

Prenatal androgen exposure has been associated with aggressive behavior in adults. It is less clear whether this association holds for childhood externalizing behavior. This study tests the hypothesis that increased prenatal androgen exposure is associated with aggressive behavior and attention problems in childhood. The ratio of the length of the second finger digit relative to the fourth digit, which is a marker for prenatal testosterone exposure, was assessed in 239 male and female fifth grade schoolchildren from Jintan, China, together with parent and teacher ratings of aggression and attention problems. Increased aggression and attention problems were both significantly associated with a lower ratio of the length of the second finger digit relative to the fourth digit ratios in boys but not girls. The effects remained significant after controlling for early adversity. These findings are the first to establish a relationship between an indirect indicator of fetal androgen exposure and any child psychopathology in Chinese children, and the observed effect size in boys was stronger than in male adults in Western studies. The results provide limited cross-cultural support for the importance of prenatal androgen exposure in contributing to the development of externalizing behavior problems in children, and they suggest that such effects may be specific to boys who may be relatively more vulnerable to early prenatal influences.

Digit Ratio (2D:4D) Moderates the Relationship Between Cortisol Reactivity and Self-Reported Externalizing Behavior in Young Adolescent Males

Although reduced cortisol reactivity to stress and increased circulating testosterone level are hypothesized to be associated with higher levels of externalizing behavior, empirical findings are inconsistent. One factor that may account for the heterogeneity in these relationships is prenatal testosterone exposure. This study examined whether the second-to-fourth digit ratio (2D:4D), a putative marker of prenatal testosterone exposure, moderates the relationships of testosterone and cortisol reactivity with externalizing behavior. Left and right hand 2D:4D and self-reported externalizing behavior were measured in a sample of 353 young adolescents (M age=11.92 years; 178 females; 79.7% African American). Saliva samples were collected before and after a stress task and later assayed for cortisol. Testosterone levels were determined from an AM saliva sample. 2D:4D interacted with cortisol reactivity to predict externalizing behavior in males, but not females. In males, low cortisol reactivity was associated with higher levels of aggression and rule-breaking behavior, but only among subjects with low 2D:4D (i.e., high prenatal testosterone). Findings suggest the importance of a multi-systems approach in which interactions between multiple hormones are taken into account. Furthermore, results demonstrate the importance of considering the organizational influence of prenatal testosterone in order to understand the activational influence of circulating hormones during adolescence.

The Biology of Childhood Crime and Antisocial Behavior

Research into the biological underpinnings of antisocial behavior has not only been increasingly integrated into criminological research, but has also expanded its scope to focus on antisocial behavior that develops during childhood. Many of the biological risk factors that are associated with antisocial behavior during adulthood have also been found to characterize young antisocials. Structural and functional brain imaging studies have implicated several brain regions in the development of antisocial behavior in children, including the amygdala, the ventromedial prefrontal cortex, and the temporal region. Neuropsychological studies indicate that antisocial children display multiple behavioral indices of brain dysfunction, including executive dysfunction and IQ deficits. Psychophysiological studies have revealed that antisocial children are characterized by underarousal and diminished responses to stimuli and stressors. Early health factors, including minor physical anomalies and prenatal nicotine exposure, both independently and in interaction with social risk factors are associated with antisocial behavior in children. Future research should focus on incorporating a life-course criminological perspective into the study of the biology of childhood crime and antisocial behavior. Longitudinal studies that measure both biological and social risk factors over time will be critical to advancing our understanding of the development of antisocial behavior both during childhood and throughout the life-course.