Genetic and Environmental Influences on Psychopathy: A Meta-Analysis of Twin Studies

Psychopathy is a multidimensional syndrome that is characterized by affective (e.g. callousness, shallow affect) and interpersonal (e.g., arrogance, manipulative) deficits and is associated with persistent antisocial behavior... [ view full abstract ]

Psychopathy is a multidimensional syndrome that is characterized by affective (e.g. callousness, shallow affect) and interpersonal (e.g., arrogance, manipulative) deficits and is associated with persistent antisocial behavior across the lifespan. Importantly, psychopathic personality traits are distinguished from psychopathic behavior.  It is theorized that these dimensions have distinct etiologies such that affective-interpersonal deficits are largely genetic in origin while associated behaviors are due to both genetic and environmental influences, but these etiological distinctions remain largely untested.  Prior meta-analyses investigating the etiology of psychopathy have been limited by a focus on behavioral features of psychopathy, rather than the personality deficits that distinguish it from other forms of externalizing behavior.  Fortunately, behavioral genetic literature on psychopathy has expanded greatly in the past decade and now includes numerous studies of both personality deficits and pathological behaviors.  Therefore, the current meta-analysis aimed to investigate the origins of personality and behavioral features of psychopathy by examining the type and magnitude of genetic and environmental influences on each.  A comprehensive literature search yielded 52 twin studies of psychopathic traits. Of these, 16 unique samples were retained for analysis.  In general, AE models provided the best fit to the data, indicating that additive genetic and unique environmental factors, but not common environmental factors, accounted for the variance in psychopathy factors and their subfacets.  However, moderation analyses indicated that there are significant sex and age differences in their etiologies.  Genetic factors explained a greater proportion of variance in females than males across psychopathic traits.  Additionally, common environmental factors are an important source of variance in childhood and adolescence for the affective/interpersonal factor, but not in adulthood or for the socially deviant factor.  These findings suggest that psychopathic dimensions may not have such distinct etiologies as previously theorized or that etiological differences depend on moderating factors, such as developmental stage.