Abstract
Researchers have long theorized that genetic influence on mental health may differ as a function of environmental risk factors. One likely moderator of genetic and environmental influences on psychopathological symptoms is parenting behavior, as phenotypic research shows that negative aspects of parent-child relationships are associated with greater likelihood of mental illness in adulthood. The current study examined whether levels of reported parental discipline and affection experienced in childhood act as a trigger, or buffer, for adult mental health problems. Results from a nationwide twin sample suggest level of father's discipline and affection, as reported by now-adult twins, moderated genetic and environmental influences on internalizing symptoms in adulthood, such that heritability was greatest at the highest levels of discipline and affection. Father's affection also moderated the etiological influences on alcohol use problems, with greater heritability at the lowest levels of affection. No moderating effect was found for mothers. Findings suggest relationships with fathers in childhood can have long-lasting effects on the etiological influences on adult mental health outcomes.