A genetic variant brain-derived neurotrophic factor (BDNF) polymorphism interacts with hostile parenting to predict error-related brain activity and thereby risk for internalizing disorders in children.

The error-related negativity (ERN) is a negative deflection in the event-related potential occurring when individuals make mistakes, and is increased in children with internalizing psychopathology. We recently found that harsh parenting predicts a larger ERN in children, and recent work has suggested that variation in the brain-derived neurotrophic factor (BDNF) gene may moderate the impact of early life adversity. Parents and children completed measures of parenting when children were 3 years old (N = 201); 3 years later, the ERN was measured and diagnostic interviews as well as dimensional symptom measures were completed. We found that harsh parenting predicted an increased ERN only among children with a methionine allele of the BDNF genotype, and evidence of moderated mediation: the ERN mediated the relationship between parenting and internalizing diagnoses and dimensional symptoms only if children had a methionine allele. We tested this model with externalizing disorders, and found that harsh parenting predicted externalizing outcomes, but the ERN did not mediate this association. These findings suggest that harsh parenting predicts both externalizing and internalizing outcomes in children; however, this occurs through different pathways that uniquely implicate error-related brain activity in the development of internalizing disorders.