Twin study of dissociative experience.

The relative influence of genetic and environmental influences on measures of pathological and nonpathological dissociative experience was estimated using a classic twin-study design. Subjects were 177 monozygotic and 152 dizygotic volunteer general population twin pairs who completed two measures of dissociative capacity identified from the items comprising the Dissociative Experiences Scale (DES). Additive genetic influences accounted for 48% and 55% of the variance in scales measuring pathological and nonpathological dissociative experience, respectively. Heritability estimates did not differ by gender. The genetic correlation between these measures was estimated at .91, suggesting common genetic factors underlying pathological and nonpathological dissociative capacity. Genetic and environmental correlations between the DES scales and measures of personality disorder traits (Dimensional Assessment of Personality Pathology-Basic Questionnaire; DAPP-BQ) were also estimated. Significant genetic correlations (median = .38) were found between the DES scales and DAPP-BQ cognitive dysregulation, affective lability, and suspiciousness, suggesting that the genetic factors underlying particular aspects of personality disorder also influence dissociative capacity.