Disorganization, COMT, and Children's Social Behavior: The Norwegian Hypothesis of Legacy of Disorganized Attachment

Disentangling genes, attachment, and environment: A systematic review of the developmental psychopathology literature on gene-environment interactions and attachment

The role of genetics in relation to attachment is of continued interest to developmental psychology. Recent research has attempted to disentangle genetic main effects, environmental effects, and gene and environment (G × E) interactions in the development of attachment security/insecurity and disorganization. We systematically reviewed associations between gene markers and attachment, including G × E interactions, identifying 27 eligible studies. Inconsistent results emerged for associations between both gene effects and G × E interactions on attachment organization. Where G × E interactions used attachment as the environmental factor in the interaction, we observed more consistent results for differential susceptibility of G × E interactions on offspring behavior. Small sample size and heterogeneity in measurement of environmental factors impacted on comparability of studies. From these results, we propose that the future of research into the role of genetic effects in attachment lies in further exploration of G × E interactions, particularly where attachment acts as an environmental factor impacting on other child developmental outcomes emerging from the caregiving environment, consistent with differential susceptibility approaches to developmental psychopathology. In addition, from a methodological perspective, establishing the role of gene markers in such models will require a shift toward contemporary genomics, including genome-wide analysis (including novel genes and chromosomal loci), and epigenetic individual variations.

Differences in Sensitivity to Environment Depending on Catechol-O-Methyltransferase (COMT) Gene? A Meta-analysis of Child and Adolescent Gene-by-Environment Studies

To date, several gene-by-environment (G×E) meta-analyses have been conducted to provide cumulative G×E evidence from previous inconsistent empirical studies; however, these meta-analyses have mainly focused on the serotonin transporter gene (5-HTTLPR). The present study aimed to conduct the first meta-analysis that tested whether and how an important dopaminergic gene-the catechol-O-methyltransferase (COMT) gene contributed to differences in child and adolescent environmental sensitivity. A total of 22 studies with 20,528 participants involving in various developmental outcomes (e.g., externalizing problems, emotional problems, cognitive development and social behaviors) met the inclusion criteria. The pooled effect size of environment-outcome associations in the Met-allele carriers (r = 0.11, 95% CI = [0.07, 0.15], p < .001) did not significantly differ from that in the Val/Val homozygotes (r = 0.14, 95% CI = [0.08, 0.20], p < 0.001) (Q_contrast (1) = 0.37, p = 0.54). The aggregated Liptak-Stouffer Z-score that combined the p-values of the COMT-environment interaction yield a nonsignificant result (p = 0.52). Moreover, outcome domain, sample age, ethnicity and assessment methods for the environment and the outcome did not moderate the effect sizes. Thus far, the COMT Val158Met polymorphism fails to explain the differences in sensitivity to environment. Future studies might incorporate more factors, such as polygenic effects of genetic pathways, epigenetics (EpiG) processing and sexual dimorphism, into the COMT-environment interaction equation.