Genetic and environmental overlap between borderline personality disorder traits and psychopathy: evidence for promotive effects of factor 2 and protective effects of factor 1

Background. Previous studies have reported strong genetic and environmental overlap between antisocial-externalizing (factor 2; F2) features of psychopathy and borderline personality disorder (BPD) tendencies. However, this line of research has yet to examine etiological associations of affective-interpersonal (factor 1, F1) features of psychopathy with BPD tendencies. Method. The current study investigated differential phenotypic and genetic overlap of psychopathy factors 1 and 2 with BPD tendencies in a sample of over 250 male and female community-recruited adult twin pairs. Results. Consistent with previous research, biometric analyses revealed strong genetic and non-shared environmental correlations of F2 with BPD tendencies, suggesting that common genetic and non-shared environmental factors contribute to both phenotypes. In contrast, negative genetic and non-shared environmental correlations were observed between F1 and BPD tendencies, indicating that the genetic factors underlying F1 serve as protective factors against BPD. No gender differences emerged in the analyses. Conclusions. These findings provide further insight into associations of psychopathic features - F1 as well as F2 - and BPD tendencies. Implications for treatment and intervention are discussed, along with how psychopathic traits may differentially influence the manifestation of BPD tendencies.