Genetic and Environmental Contributions to Linkages Between Maternal Trauma and Child Internalizing and Externalizing Behavior Problems

INTRODUCTION: Maternal trauma is a complex risk factor that can interfere with child-rearing and has been linked to adverse child development outcomes, including internalizing and externalizing behavior problems (Morrel et. al., 2003). Nevertheless, it remains unclear whether this association is genetic or environmental in nature. To address this gap, we examine the link between maternal trauma and child internalizing and externalizing behaviors in an adoption sample of biological mothers, adoptive mothers, and adopted children. Given that exposure to trauma is largely an environmental influence, we expected to find a significant association between adoptive mother’s trauma history and adopted child behavior problems, and a non-significant link between biological mother’s trauma history and adopted child’s behavior problems.

METHODS: Current sample (N=260; child mean age=7 years) was obtained from the Early Growth Development Study- an ongoing longitudinal study of birth parents, adoptive families, adopted children, and biological siblings. Biological mother’s trauma was assessed using a cumulative score of lifetime number of traumatic events (e.g., sexual/physical abuse) prior to pregnancy. Adoptive mother’s trauma history was assessed using 9 items from the Negative Life Events Scale, matched to the trauma items assessed in biological mothers (e.g., experienced a robbery). Child’s internalizing and externalizing problems were assessed using parents’ reports on the Child Behavior Checklist.

RESULTS: As hypothesized, we found no significant association between biological mother’s trauma history and adopted child’s internalizing (r= - 0.01, p =0.47) or externalizing behaviors (r= 0.00, p =0.48). Adoptive mother’s trauma was however significantly correlated with adopted child’s internalizing problems (r= 0.16, p <0.05), and marginally related to externalizing problems (r= 0.11, p =0.08). To further understand this influence, we will expand these preliminary findings by (a) exploring the mediating role of maternal depressive symptoms, and (b) evaluating the effect of biological mother’s trauma on behavior problems in the biological sibling of the adopted child, being raised by the biological mother.

CONCLUSION: Understanding the relationship between maternal trauma and child outcomes is crucial in the development of effective interventions for mothers and prevention of child behavior problems. Given the lack of a shared genetic link between the adoptive mother and adopted child, evidence of a significant association suggests that the influence of maternal trauma is primarily environmental. Prevention efforts targeting malleable factors in the rearing environment may help ameliorate negative influences of maternal trauma on child outcomes.