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Genetic and environmental contributions to dimensions of personality disorder
W J Livesley1, K L Jang, D N Jackson
1Department of Psychiatry, Faculty of Medicine, University of British Columbia, Vancouver, Canada.
Objective:
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.
Method:
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.
Results:
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.
Conclusions:
These results are similar to those reported for normal personality and suggest a continuity between normal and disordered personality.