2013

Current cognitive-motivational theories of addiction propose that prioritizing appetitive, reward-related information (attentional bias) plays a vital role in the development and maintenance of substance abuse. This study focused on reward-related attentional processes that might be involved in young-adolescent substance use. Participants were young adolescents (N = 682, mean age = 16.14), who completed a motivated game in the format of a spatial orienting task as a behavioral index of appetitive-related attentional processes and a questionnaire to index substance (alcohol, tobacco, and cannabis) use. Correlational analysis showed a positive relationship between substance use and enhanced attentional engagement, with cues that predicted potential reward and nonpunishment. These results are consistent with the view that adolescents who show a generally enhanced appetitive bias might be at increased risk for developing heavier substance use.

The quality of adolescents' relationships with peers can have a lasting impact on later psychosocial adjustment, mental health, and behavior. However, the effect of peer relations on later problem behavior is not uniformly strong, and genetic factors might influence this association. This study used four-wave longitudinal (11-19 years) data (n = 1,151) from the Tracking Adolescents' Individual Lives Survey, a Dutch cohort study into adolescent development to test whether the dopamine receptor D4 polymorphism moderates the impact of negative (i.e., victimization) and positive peer experiences (i.e., social well-being) on later delinquency. Contrary to our expectations, results showed that carriers of the dopamine receptor D4 gene 4-repeat homozygous variant instead of those carrying the 7-repeat allele were more susceptible to the effects of both peer victimization and social well-being on delinquency later in adolescence. Findings of our study are discussed in light of other studies into genetic moderation of peer effects on adolescent development and the possibility that developmental specifics in adolescence, such as maturation processes in brain structure and functioning, may affect the interplay of environmental and genetic factors in this period in life.

Objective: Physical activity is inversely associated with depression in adolescents but the overall associations are fairly weak, suggesting individual differences in the strength of the associations. The aim of this study was to investigate whether plasticity genes modify the reciprocal prospective associations between physical activity and depressive symptoms found previously. Methods: In a prospective population-based study (N=1196), physical activity and depressive symptoms were assessed three times, around the ages of 11, 13.5 and 16. Structural Equation Modeling was used to examine reciprocal effects of physical activity and depressive symptoms over time. The plasticity genes examined were 5-HTTLPR, DRD2, DRD4, MAOA, TPH1, 5-HTR2A, COMT, and BDNF. A cumulative gene plasticity index consisting of three groups (low, intermediate and high) according to the number of plasticity alleles carried by the adolescents was created. Using a multi-group approach we examined if the associations between physical activity and depressive symptoms differed between the three cumulative plasticity groups as well as between the individual polymorphisms. Results: We found significant cross-sectional and cross-lagged paths from physical activity to depressive symptoms and vice versa. Neither the cumulative plasticity index nor the individual polymorphisms modified the strengths of these associations. Conclusion: Associations between adolescents’ physical activity and depressive symptoms are not modified by plasticity genes.

Although externalizing behavior problems show in general a high stability over time, the course of externalizing behavior problems may vary from individual to individual. Our main goal was to investigate the predictive role of parenting on externalizing behavior problems. In addition, we investigated the potential moderating role of gender and genetic risk (operationalized as familial loading of externalizing behavior problems (FLE), and presence or absence of the DRD4 7-repeat and 4-repeat allele, respectively). Perceived parenting (rejection, emotional warmth, and overprotection) and FLE were assessed in a population-based sample of 1768 10- to 12-year-old adolescents. Externalizing behavior problems were assessed at the same age and 212 years later by parent report (CBCL) and self-report (YSR). DNA was extracted from blood samples. Parental emotional warmth predicted lower, and parental overprotection and rejection predicted higher levels of externalizing behavior problems. Whereas none of the parenting factors interacted with gender and the DRD4 7-repeat allele, we did find interaction effects with FLE and the DRD4 4-repeat allele. That is, the predictive effect of parental rejection was only observed in adolescents from low FLE families and the predictive effect of parental overprotection was stronger in adolescents not carrying the DRD4 4-repeat allele.