Background: Clinical and epidemiological observation over the past five decades indicates that severe adverse experience, depression, and anxiety in one generation are associated with elevated psychiatric morbidity in children and, in some populations, grandchildren, a phenomenon variously described as intergenerational,transgenerational, or historical trauma. Objective: To synthesize evidence on how parental adverse experience, depression, and anxiety affect the mental health of children and grandchildren; to characterize the molecular pathology of the proposed epigenetic mechanisms; to examine prenatal and fetal programming pathways in depth; and to evaluate which treatments have been attempted and which have demonstrated success in interrupting this transmission.