Extending the developmental and behavior genetic literature of psychopathy from a personality-based approach: continuity and change from adolescence to adulthood and gene-environment interplay

Abstract

Objective: In two studies, this dissertation investigated the development and etiology of psychopathy from a personality-based approach. Study one examined patterns of continuity and change in psychopathic traits of Fearless Dominance (FD) and Impulsive Antisociality (IA) from late adolescence to early adulthood. Study two tested models of gene-environment interplay between psychopathic traits and deviant peer affiliation (DPA) in late adolescence. Method: Both studies used a community sample of male and female twins from the Minnesota Twin-Family Study (MTFS). Utilizing the older cohort of the MTFS, study one examined rank-order, mean- and individual-level change in self-reported FD and IA, measured via the Multidimensional Personality Questionnaire (MPQ; Tellegen, in press), at ages 17 and 24. In addition, study one employed longitudinal-biometric models to decompose stable and unique sources of variance across time into genetic and environmental contributions. Study two used twins from both the younger and older MTFS cohorts at the age 17 assessments to explore whether genetic and environmental sources of variance in FD and IA are moderated by DPA. Results: FD and IA exhibited comparable rank-order stability yet divergent patterns of mean- and individual-level change. Biometric analyses observed greater genetic variance for stability and greater nonshared environmental variance for change over time. Biometric moderation was suggested for men with declining genetic effects for IA in the context of significant genetic correlations with DPA for both FD and IA. In women, nonshared environmental effects increased as a function of DPA in FD and IA. Conclusions: The results extend the growing body of developmental and behavior genetic research on psychopathy from a personality-based conceptualization.