2009

Background: Accumulating evidence suggests that there is a rich and varied interplay between persons and their environments, which strongly suggests that this involves gene-environment correlations and interactions. We investigated whether familial risk (FR) to externalizing problems and prenatal and perinatal risk factors, separately or in interaction with each other, predicted externalizing behaviors. Methods: The subjects were 10- to 12-year-old preadolescents who were taking part in TRAILS, a large prospective population-based cohort study (N=2230). Regression analyses were used to determine the relative contribution of FR and prenatal and perinatal risks to parent and teacher ratings of inattention, aggression, and delinquency. Results: Regression models explained between 6 and 11% of the variance of externalizing behaviors. We found main effects of FR (vs. no FR), macrosomia (birth weight >4500g), maternal prenatal smoking (MPS), pregnancy and delivery complications (PDCs), and gender that were rather consistent across rater and outcome measures. For some outcome measures, the effect of MPS and PDCs depended on the presence of FR. These included both positive and negative interaction effects. Correlations between FR and prenatal and perinatal risks were significant but rather low. Conclusions: Both main effects and interaction effects of FR and prenatal and perinatal risks contribute to externalizing behaviors in preadolescents, but all effects were of small size. Further research including use of candidate gene polymorphisms is necessary to identify the underlying neurobiological mechanisms of these main and interaction effects.

The aim of this study was to examine the relations between popularity and different types of aggressive, destructive, and norm-breaking behaviors in a large cross-sectional sample of adolescents (N = 3312 / M age =14.02). We were interested in the extent to which the relations of these behaviors with popularity were moderated by positive features (i.e., athletic abilities, physical attractiveness, and prosociality). From a goal-framing perspective, it was argued that positive features evoke positive affect, which in turn enhances the positive impact of aggressive, destructive, and norm-breaking behaviors on popularity. The results supported our notion that these latter behaviors are especially related to popularity in adolescents who also exhibit positive features.

Objective: To examine whether HPA-axis activity mediates the relationship between obstetric complications (OCs) and externalizing behavior problems, and to investigate whether this model is different for boys and girls. In a population-based cohort of 1,768 10- to 12-year-old early adolescents, we assessed the cortisol awakening response and evening cortisol levels. Externalizing behavior problems were assessed using the Child Behavior Checklist and the Youth Self-Report. OCs were retrospectively assessed in a parent interview. OCs significantly predicted externalizing behavior problems, but OCs did not predict HPA-axis activity. Thus, the mediation model was not supported. In addition to the relationship between HPA-axis activity and externalizing behavior problems, which is specific for girls, there is also a relationship between OCs and externalizing behavior problems. However, these two mechanisms are not related to each other indicating that HPA-axis activity is not a mediator in the relationship between OCs and externalizing behavior problems. Future research should focus on understanding the mechanism through which OCs cause externalizing behavior problems.

Possible differences between childhood-limited antisocial youths and their stable high counterparts were examined. Children were 11 years old at T1 and 13.5 at T2. At both waves the same self-, parent, and teacher reports of antisocial behavior were used. Stable highs and childhood-limited antisocial youths differed somewhat in family and individual background. Stable highs had less effortful control, perceived more overprotection, had a higher level of familial vulnerability to externalizing disorder, and lived less often with the same parents throughout their lives than the childhood-limited group. Both groups had similar levels of service use before T1, but after that period the childhood-limited youths received more help from special education needs services than from problem behavior services; and vice versa for stable highs. The results suggest that the childhood-limited antisocial youths recovered not only from antisocial behavior, but also from academic failure, peer rejection, and internalizing problems.