Kiriakos Xenitidis and Colin Campbell

The conclusions drawn by Auty et al – that the development and persistence of psychopathic personality characteristics is most likely down to both genetic and environmental factors – are well-judged, modest, and consistent with their results. Their report highlights a large and potentially important dataset, and the topic of intergenerational transmission of personality characteristics is underresearched. Unfortunately, although it was not mentioned in the limitations, I am concerned that the results of the analysis remain open to confounding by genetic factors. For example, the mediation model involving disrupted employment as an intergenerational mediator of psychopathic trait from one generation to the next (male and female) was statistically significant. But, in finding that unemployment was a cause of psychopathic traits in the offspring, given that some genetic influence to psychopathy exists, and that correlation between genetic risk for psychopathy and unemployment is likely, the conclusions seem vulnerable to the alternative explanation that it is shared genetic material, not psychosocial risk factors, being measured in the models. This could be an important threat to inference. For example, in the study of intergenerational transmission of conduct problems by D’Onofrio et al, the investigators identified evidence for complete confounding of environmental risk factors by shared genetic liability. Readers should be cautious, therefore; bringing about changes in personality structure in the offspring of psychopathic individuals by intervening in the parental psychosocial environment may be injudicious.