Editorial: The Value of Genetically Informative Designs to Understand Pathways of Intergenerational Transmission and Direction of Causality.

One of the greatest challenges in the social, behavioral, and medical sciences is to determine the causality underlying associations between risk factors and behavioral or disease outcomes. An area in which insight into causality, and especially direction of causation of possible risk factors and outcomes, could have enormous (clinical) impact is the field of childhood and adolescent psychiatry. Abundant evidence shows that psychopathology runs in families, but the pathways underlying shared family risk are unclear. Large twin family studies provide robust estimates for the heritability of childhood and adolescent behavioral and emotional problems, but direct non-genetic effects from parent to offspring or vice versa cannot be excluded. Question remains as to whether there is a direct causal effect of parental mental health status on the mental health and well-being of their offspring above and beyond the transmission of genetic susceptibility. Genetically informed methods provide opportunities to tackle this causality challenge.