Genetic and environmental contributions to dimensions of personality disorder

TLDR

Factor analytic studies identified a stable structure underlying personality disorders in clinical and nonclinical subjects, forming the basis for the questionnaire. The study estimated the heritability and the relative contributions of genetic and environmental sources to basic personality disorder dimensions. Using 175 twin pairs, each completed the Dimensional Assessment of Personality Pathology, and structural equation modeling estimated additive genetic, common, and unique environmental effects. Heritability ranged from 0 % for conduct problems to 64 % for narcissism, with submissiveness and attachment problems showing low heritability, and the best‑fitting models involved additive genetic and unique environmental effects, indicating continuity with normal personality.

Abstract

The authors estimated the heritability of the basic dimensions of personality disorder and the relative proportions of the variance attributable to genetic and environmental sources.The subjects were 175 volunteer twin pairs (90 monozygotic and 85 dizygotic) from the general population. Each twin completed the Dimensional Assessment of Personality Pathology, a questionnaire that assesses 18 dimensions of personality disorder. The questionnaire was developed on the basis of factor analytic studies that identified a stable structure underlying personality disorders in clinical and nonclinical subjects. Structural equation model-fitting methods were used to estimate the influence of additive genetic, common environmental, and unique environmental effects.The estimates of broad heritability ranged from 0%, for conduct problems, to 64%, for narcissism. Behaviors associated with submissiveness and attachment problems had low heritability. For most dimensions, the best-fitting model was one that specified additive genetic and unique environmental effects.These results are similar to those reported for normal personality and suggest a continuity between normal and disordered personality.