2018

Background. Various childhood social experiences have been reported to predict adult outcomes. However, it is unclear how different social contexts may influence each other's effects in the long run. This study examined the joint contribution of adolescent family and peer experiences to young adult wellbeing and functioning. Methods. Participants came from the TRacking Adolescents' Individual Lives Survey (TRAILS) study (n = 2230). We measured family and peer relations at ages 11 and 16 (i.e. family functioning, perceived parenting, peer status, peer relationship quality), and functioning as the combination of subjective wellbeing, physical and mental health, and socio-academic functioning at age 22. Using structural equation modelling, overall functioning was indicated by two latent variables for positive and negative functioning. Positive, negative and overall functioning at young adulthood were regressed on adolescent family experiences, peer experiences and interactions between the two. Results. Family experiences during early and mid-adolescence were most predictive for later functioning; peer experiences did not independently predict functioning. Interactions between family and peer experiences showed that both protective and risk factors can have context-dependent effects, being exacerbated or overshadowed by negative experiences or buffered by positive experiences in other contexts. Overall the effect sizes were modest at best. Conclusions. Adolescent family relations as well as the interplay with peer experiences predict young adult functioning. This emphasizes the importance of considering the relative effects of one context in relation to the other.

From the literature it is not clear whether low resting heart rate (HR) reflects low or high sensitivity to the detrimental effects of adverse environments on externalizing problems. We studied parental psychiatric history (PH), reflecting general vulnerability, as possible moderator explaining these inconsistencies. Using Linear Mixed Models, we analyzed data from 1914 subjects, obtained in three measurement waves (mean age 11, 13.5, and 16 years) from the TRacking Adolescents' Individual Lives Survey population-based cohort and the parallel clinic-referred cohort. As hypothesized, more chronic stressors predicted more externalizing problems in vulnerable individuals with high resting HR but not in those with low resting HR, suggesting high vs. low sensitivity, respectively, to adverse environmental influences. Low sensitivity to adverse environmental influences in vulnerable individuals exposed to high stressor levels was additionally confirmed by high heart rate variability (Root Mean Squared Successive Difference; RMSSD). In adolescents with low vulnerability, in contrast, the association between chronic stressors and externalizing problems did not substantially differ by resting HR and RMSSD. Future research may demonstrate whether our findings extend to other adverse, or beneficial, influences. Notwithstanding their theoretical interest, the effects were small, only pertained to parent-reported externalizing problems, refer to a small subset of respondents in our sample, and are in need of replication. We conclude that HR and RMSSD are unlikely to be strong moderators of the association between stressors and externalizing problems.

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The existing literature does not provide consistent evidence that carriers of the Dopamine D4 Receptor 7-repeat allele are more sensitive to adverse environmental influences, resulting in enhanced externalizing problems, compared to noncarriers. One explanation is that the adverse influences examined in prior studies were not severe, chronic, or distressing enough to reveal individual differences in sensitivity reflected by DRD4–7R. This study examined whether the 7-repeat allele moderated the association between chronic stressors capturing multiple stressful aspects of individuals’ lives and externalizing problems in adolescence. We expected that chronic stressor levels would be associated with externalizing levels only in 7-repeat carriers. Using Linear Mixed Models, we analyzed data from 1621 Dutch adolescents (52.2% boys), obtained in three measurement waves (mean age approximately 11, 13.5, and 16 years) from the TRacking Adolescents’ Individual Lives Survey (TRAILS) population-based birth cohort and the parallel clinic-referred cohort. Across informants, we found that higher levels of chronic stressors were related to higher externalizing levels in 7-repeat carriers but not in noncarriers, as hypothesized. Although previous studies on the 7-repeat allele as a moderator of environmental influences on adolescents’ externalizing problems have not convincingly demonstrated individual differences in sensitivity to adverse environmental influences, our findings suggest that adolescent carriers of the Dopamine D4 Receptor 7-repeat allele are more sensitive to chronic, multi-context stressors than noncarriers.