Socioeconomic status mediates the genetic contribution of the dopamine receptor D4 and serotonin transporter linked promoter region repeat polymorphisms to externalization in preadolescence

Abstract

The impact of socioeconomic status (SES) and genetic polymorphisms on individual differences for externalized behaviors have often been investigated separately in studies of children and adults. In a general population sample of 607 Italian preadolescents, we examined the independent and joint effects of SES and the dopamine receptor D4 (DRD4) and serotonin transporter linked promoter region (5-HTTLPR) polymorphisms upon rule-breaking and aggressive behaviors measured with the Child Behavior CheckList/6-18. We found evidence, which was based on both one locus and two-loci genotype analyses, that low SES and DRD4 long and 5-HTTLPR long alleles, both alone and in interaction, are associated with higher aggressive behavior scores. The effects were similar but more modest and limited to one locus genotype analyses for rule-breaking behavior. Consistent with studies that showed the effects of societal moderators on the heritability of externalized behaviors across different segments of the population, we suggest that diminished social constraints associated with low parental SES may act as enhancers of the genetic influence of specific DRD4 and 5-HTTLPR alleles over aggressive behaviors in preadolescence.

COMT Val158Met polymorphism and socioeconomic status interact to predict attention deficit/hyperactivity problems in children aged 10–14

“…Moreover, there were no significant differences owing to SES (t = -0.72, p = 0.47) or age (t = -1.34, p = 0.18) between PrISMA children belonging to families who agreed versus those belonging to families who did not agree to participate in the genetic study [41].…”

“…Previous controls for biases performed upon demographic and behavioural variables showed no, or only modestly significant differences in behavioural variables in children belonging to families who agreed versus those belonging to families who did not agree to participate in the genetic study [41,42]. Moreover, there were no significant differences owing to SES (t = -0.72, p = 0.47) or age (t = -1.34, p = 0.18) between PrISMA children belonging to families who agreed versus those belonging to families who did not agree to participate in the genetic study [41].…”

“…Although attending the same school grade, children in the PrISMA sample were slightly older than children in the PL sample, due to a modest difference in the timing of recruitment of the two samples (winter for the PrISMA sample and fall for the PL sample [41,42]). …”

“…Since the inclusion (age between 10 and 14 years, parental written informed consent) and exclusion criteria (certification of mental handicap, which was present in 0.3% of eligible participants) and the psychometric instrument (parental assessments of children behaviour through the CBCL/6-18) were the same for the PrISMA and the PL samples, after controlling for the homogeneity of demographic and behavioural variables, as in two previous studies regarding externalizing behaviour and affective problems [41,42], for the present study we pooled together subjects of both epidemiological samples to increase the statistical power.…”

Gene×Environment Interactions in Early Externalizing Behaviors: Parental Emotional Support and Socioeconomic Context as Moderators of Genetic Influences?

“…A number of previous studies have detected gene × parenting and gene × SES interactions on externalizing behaviors; however, the direction of these detected interactions have been inconsistent, with some studies reporting that genes play a less important role at higher level of positive parenting (e.g., DiLalla et al, 2009;Feinberg et al, 2007) or higher SES (e.g., Nobile, et al, 2007), while others reported the opposite pattern (e.g., Brody et al, 2009;Leve et al, 2009;Tuvblad et al, 2006). In the following sections, we first review the extant genetic and socialization literatures on externalizing behaviors, and then describe the utility of a gene × environment interaction approach.…”