The heritability of Cluster A personality disorders assessed by both personal interview and questionnaire

University of Oslo, Kristiania (historical), Oslo, Norway
Psychological Medicine (Impact Factor: 5.94). 06/2007; 37(5):655-65. DOI: 10.1017/S0033291706009755
Source: PubMed


Personality disorders (PDs) as assessed by questionnaires and personal interviews are heritable. However, we know neither how much unreliability of measurement impacts on heritability estimates nor whether the genetic and environmental risk factors assessed by these two methods are the same. We wish to know whether the same set of PD vulnerability factors are assessed by these two methods.
A total of 3334 young adult twin pairs from the Norwegian Institute of Public Health Twin Panel (NIPHTP) completed a questionnaire containing 91 PD items. One to 6 years later, 1386 of these pairs were interviewed with the Structured Interview for DSM-IV Personality (SIDP-IV). Self-report items predicting interview results were selected by regression. Measurement models were fitted using Mx.
In the best-fit models, the latent liabilities to paranoid personality disorder (PPD), schizoid personality disorder (SPD) and schizotypal personality disorder (STPD) were all highly heritable with no evidence of shared environmental effects. For PPD and STPD, only unique environmental effects were specific to the interview measure whereas both environmental and genetic effects were found to be specific to the questionnaire assessment. For SPD, the best-fit model contained genetic and environmental effects specific to both forms of assessment.
The latent liabilities to the cluster A PDs are highly heritable but are assessed by current methods with only moderate reliability. The personal interviews assessed the genetic risk for the latent trait with excellent specificity for PPD and STPD and good specificity for SPD. However, for all three PDs, the questionnaires were less specific, also indexing an independent set of genetic risk factors.


Available from: Michael C Neale
    • "For OCPD, there are, to the best of our knowledge, no previous studies with which to compare our result. However, the latent heritability of 0.53 is slightly lower than what has been found for dimensional representations of the other nine DSM-IV PDs – which ranged from 0.55 to 0.72 (Kendler et al. 2007; Gjerde et al. 2012; Torgersen et al. 2012). This fits well with the findings from previous studies on PD heritability from our group (Reichborn-Kjennerud et al. 2007), where OCPD was found to have a lower amount of the total variance explained by genetic variance, compared to AVPD and dependent PD. "
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    ABSTRACT: Background. The phenotypic stability of avoidant personality disorder (AVPD) and obsessive-compulsive personality disorder (OCPD) has previously been found to be moderate. However, little is known about the longitudinal structure of genetic and environmental factors for these disorders separately and jointly, and to what extent genetic and environmental factors contribute to their stability. Method. AVPD and OCPD criteria were assessed using the Structured Interview for DSM-IV Personality in 2793 young adult twins (1385 pairs, 23 singletons) from the Norwegian Institute of Public Health Twin Panel at wave 1 and 2282 (986 pairs, 310 singletons) of these on average 10 years later at wave 2. Longitudinal biometric models were fitted to AVPD and OCPD traits. Results. For twins who participated at both time-points, the number of endorsed sub-threshold criteria for both personality disorders (PDs) decreased 31% from wave 1 to wave 2. Phenotypic correlations between waves were 0.54 and 0.37 for AVPD and OCPD, respectively. The heritability estimates of the stable PD liabilities were 0.67 for AVPD and 0.53 for OCPD. The genetic correlations were 1.00 for AVPD and 0.72 for OCPD, while the unique environmental influences correlated 0.26 and 0.23, respectively. The correlation between the stable AVPD and OCPD liabilities was 0.39 of which 63% was attributable to genetic influences. Shared environmental factors did not significantly contribute to PD variance at either waves 1 or 2. Conclusion. Phenotypic stability was moderate for AVPD and OCPD traits, and genetic factors contributed more than unique environmental factors to the stability both within and across phenotypes.
    Psychological Medicine 08/2015; 45(16). DOI:10.1017/S0033291715001440 · 5.94 Impact Factor
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    • "The size of the subsample required a dimensional scoring of the personality disorders, counting numbers of endorsed full and sub-threshold criteria for each individual. The interrater polychoric correlations ranged from .86 to .94 for the cluster A disorders (Kendler et al., 2007), from .80 to .94 for cluster B disorders (Torgersen et al., 2008), from .87 to .97 for cluster C disorders (Reichborn-Kjennerud et al., 2007) and from .95 to .97 for appendix diagnoses (Czajkowski et al., 2008; Ørstavik et al., 2007). "
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    ABSTRACT: Behavioral genetics research has opened a new window on understanding personality disorder. The earliest studies were focused on establishing the relative contributions of genes and the environment in these disorders. Although these studies provided solid evidence of the importance of genetic and environmental influences on personality disorder and showed that all aspects of personality disorder are subject to genetic influence, heritability studies are limited because they are not helpful in explicating causal mechanisms. More recent research has focused on the relative contributions of the covariation of personality disorder diagnoses and traits, which allows one to examine etiological relationships. These developments are leading to major changes in ideas about what constitutes the environment and nature of the interplay between genes and environment. The present review examines major themes in this growing body of research in the context of current issues in the personality disorders.
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