Can a warm and supportive adult protect against mental health problems amongst children with experience of adversity? A twin-differences study

Background: Adverse childhood experiences (ACEs) are associated with mental health problems, but many children who experience ACEs do not develop such difficulties. A warm and supportive adult presence in childhood is associated with a lower likelihood of developing mental health problems after exposure to ACEs. However, it is unclear whether this association is causal, as previous research has not accounted for genetic and environmental confounding. Methods: We used the twin-difference design to strengthen causal inference about whether a warm and supportive adult presence protects children exposed to ACEs from mental health problems. Participants were from the Environmental Risk (E-Risk) Longitudinal Twin Study, a UK population-representative birth cohort of 2,232 same-sex twins. ACEs were measured prospectively from ages 5 to 12. Maternal warmth was assessed at ages 5 and 10 through maternal speech samples. Adult support was assessed through child reports at age 12. Mental health problems were assessed through interviews at age 12 with parents and teachers and participants at age 18. Results: Among children exposed to ACEs, those who experienced greater maternal warmth and adult support had lower levels of mental health problems at ages 12 and 18. In monozygotic twin-difference analyses, the protective effects of maternal warmth and adult support on mental health were attenuated by 70% for maternal warmth and 81% for adult support, compared to phenotypic analyses. Twins who experienced greater maternal warmth and adult support had minimal or no difference in mental health compared to their co-twins, concordant for ACE exposure. Conclusions: The apparent protective effect of a warm, supportive adult against mental health problems following ACEs is largely explained by genetic and environmental confounding. This suggests that interventions which boost maternal warmth and adult support should be supplemented by components addressing wider family environments and heritable vulnerabilities in children exposed to adversity, to improve mental health.