Developmental trajectories of behavioral inhibition from infancy to age seven: The role of genetic and environmental risk for psychopathology

The present study leveraged data from a longitudinal adoption study of 361 families recruited between 2003 and 2010 in the United States. We investigated how psychopathology symptoms in birth parents (BP; M_age = 24.1 years; 50.5–62.9% completed high school) and adoptive parents (AP; M_age = 37.8 years; 80.9% completed college; 94% mother–father couples) influenced children's behavioral inhibition (BI) trajectories. We used latent growth models of observed BI at 18 and 27 months, and 4.5 and 7 years in a sample of adopted children (Female = 42%, White = 57%, Black = 11%, Multi-racial = 21%, Latinx = 9%). BI generally decreased over time, yet there was substantial variability in these trajectories. Neither BP nor AP psychopathology symptoms independently predicted systematic differences in BI trajectories. Instead, we found that AP internalizing symptoms moderated the effects of BP psychopathology on trajectories of BI, indicating a gene by environment interaction.