Psychological Medicine



Original Article

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


KENNETH S. KENDLER a1a2c1, JOHN MYERS a1, SVENN TORGERSEN a3, MICHAEL C. NEALE a1a2 and TED REICHBORN-KJENNERUD a4
a1 Department of Psychiatry, Medical College of Virginia of Virginia Commonwealth University, Richmond, VA, USA
a2 Human Genetics, Medical College of Virginia of Virginia Commonwealth University, Richmond, VA, USA
a3 Institute of Psychology, University of Oslo, Center for Child and Adolescent Mental Health Eastern and Southern Norway and Nic Waal's Institute, Norway
a4 Division of Mental Health, Norwegian Institute of Public Health and the Institute of Psychiatry, University of Oslo, Norway

Article author query
kendler ks   [PubMed][Google Scholar] 
myers j   [PubMed][Google Scholar] 
torgersen s   [PubMed][Google Scholar] 
neale mc   [PubMed][Google Scholar] 
reichborn-kjennerud t   [PubMed][Google Scholar] 

Abstract

Background. 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.

Method. 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.

Results. 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.

Conclusions. 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.

(Published Online January 16 2007)


Correspondence:
c1 Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University Medical School, Box 980126, 800 E. Leigh Street, Room 1-123, Richmond, VA 23298-0126, USA. (Email: kendler@vcu.edu)


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