Antisocial Behaviour in Boys and Girls: A Review and Two Longitudinal Studies of the Developmental Origins

Abstract

Research seeking to understand the developmental origins of antisocial behaviour (ASB) has depended on complex theories and analyses, as well as multidisciplinary approaches. Such complexity comes from considering how different aspects of individuals’ lives may interact to explain the change in their ASB over the lifespan. Overall, developmental theories support that ASB originates in a mix of adverse socio-environmental circumstances and individual characteristics (e.g., temperament and mental health conditions) that vary in number and seriousness between people but also within the same individual over the life course. However, one of the main challenges of studying ASB development is the substantial heterogeneity in its manifestation, which includes distinct aggression forms (e.g., physical, verbal, relational) and specific rule-breaking behaviours (e.g., vandalism, gang membership, stealing). In this respect, much is yet to be understood about specific risks, which could be successfully identified in childhood, for distinct types of ASB into adolescence. Therefore, focusing on ASB and its developmental origins, this thesis is composed of one systematic review and two prospective longitudinal studies. The systematic review summarised the results from 31 prospective longitudinal studies reporting on childhood predictors of distinct ASB trajectories (Study 1). Drawing from a 7-wave national Australian sample, the two prospective longitudinal studies tested age four childhood predictors of boys’ and girls’ physical aggression (Study 2) and rule-breaking (Study 3) into late adolescence. The predictors tested in Studies 2 and 3 were effortful control deficits and specific features of both negative emotionality (anger, fear, and sadness dysregulation) and callous-unemotional traits (callous-lack of empathic concern for others). In Studies 2 and 3, in addition to direct effects of the tested predictors, possible catalyst effects were also tested, whereby the presence of callous-lack of empathic concern for others at age four was expected to intensify associations of effortful control deficits and anger, fear and sadness dysregulation with physical aggression and rule-breaking behaviours. Furthermore, the examination of sex differences was a particular focus in both Studies 2 and 3. The main results of the systematic review (Study 1) suggested that, overall, higher levels of chronic ASB, relative to no/low-stable ASB, can be predicted by a wide range of risk factors measured in childhood. Also, there was no evidence of sex differences in the socio-environmental risks for ASB. Still, a few sex-specificities were found in individual-level risks (i.e., the risks that were identified as significantly related to ASB in one sex, but not the other), as their higher level in childhood was associated with a higher level and more chronic ASB for girls more consistently than for boys. The main results from Studies 2 and 3 showed that all tested individual-level risks measured at age four were associated with either a higher intercept or with change (i.e., linear or U-shaped pattern of change over time) in aggression (Study 2) and with more frequent rule-breaking (Study 3) into adolescence. In Study 2, the significance of associations did somewhat differ depending on whether physical aggression was reported by mothers or selfreported. Also, callous-lack of empathic concern for others enhanced the positive association of effortful control deficits and anger dysregulation with physical aggression into late adolescence (Study 2). This catalyst effect was not observed for rule-breaking behaviour (Study 3). Notably, in both Studies 2 and 3, there was no evidence of significant sex differences in associations of any of the age four risk factors tested and either physical aggression or rule-breaking behaviours over time. Still, a few specific individual-level risks tested did seem to posit an increased risk for ASB in boys only or girls only. Two general conclusions can be drawn from these studies. First, although many risk factors were identified across all three studies, the lack of consensus in the literature about the distinct descriptions of ASB development, and the many ways of identifying and measuring risk factors, pose challenges to the consolidation of the findings. Second, risks for ASB development can be identified in childhood, and risks for physical aggression and rulebreaking into adolescence can be identified as early as age four. However, the degree to which the considerable sex differences in ASB levels could be explained/predicted by socioenvironmental and individual-level risks measured in childhood is still not clear. Findings in this thesis can be applied to inform risk assessment and intervention services for young children most at-risk for chronic or elevated ASB into adolescence and adulthood. These include, for instance, upskilling young children’s effortful control, anger regulation, and empathic concern for others to mitigate both physical aggression and rule-breaking during adolescence, when the prevalence of ASB increases substantially for both boys and girls. Also, sex-specific prevention initiatives could be useful, mainly concerning the trait of callous-lack of empathic concern for others in girls and effortful control deficits in boys. Still, anger dysregulation is a core risk factor, hence, a relevant specifier of chronic ASB for both sexes. As such, it should be targeted in prevention programs and child- or family-based interventions with both boys and girls. Study limitations and directions for future research are also discussed within each study chapter and also in the final chapter of this thesis.