title: Heritability of type-D personality.
abstract: OBJECTIVE
  To quantify the influence of genes and environment on individual differences in type-D status, and the type-D subcomponents negative affectivity and social inhibition. Type-D personality independently predicts poor prognosis in patients with cardiovascular disease. However, no previous study has determined the heritability of type-D personality.
  
  
  METHODS
  This study determined type-D personality by applying the "combination of scales" method to survey data collected by the Netherlands Twin Register in 3331 healthy, young adult twins. Using structural equation modeling (SEM), the relative contributions of additive genetic, nonadditive genetic, and nonshared environmental factors to the variance in type-D and its subcomponents were determined.
  
  
  RESULTS
  SEM indicated that type-D personality was substantially heritable (52%). The subcomponents negative affectivity and social inhibition were equally heritable, with broad heritability estimates of 46% and 50%. Although negative affectivity was determined by additive genetic effects and nonshared environment, individual differences in social inhibition were predominantly determined by nonadditive genetic effects and nonshared environment.
  
  
  CONCLUSIONS
  This study provides strong evidence that genes are important in determining individual differences in type-D personality and the type-D subcomponents negative affectivity and social inhibition.
authors.affiliation: CoRPS-Center of Research on Psychology in Somatic diseases, Department of Medical Psychology, Tilburg University, P.O. Box 90153, 5000 LE Tilburg, The Netherlands. h.m.kupper@uvt.nl
authors.forename: Nina
authors.initials: N
authors.lastname: Kupper
authors.forename: Johan
authors.initials: J
authors.lastname: Denollet
authors.forename: Eco J C
authors.initials: EJ
authors.lastname: de Geus
authors.forename: Dorret I
authors.initials: DI
authors.lastname: Boomsma
authors.forename: Gonneke
authors.initials: G
authors.lastname: Willemsen
mesh_terms: D000293:Adolescent; D000328:Adult; D000339:Affect; D015331:Cohort Studies; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D007398:Interpersonal Relations; D008297:Male; D009426:Netherlands; D010551:Personality / Q000145:classification*; D010554:Personality Disorders / Q000235:genetics* / Q000523:psychology; D011379:Prognosis; D011569:Psychiatric Status Rating Scales