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Concordance between personality disorder assessment methods
- G. Nestadt, C. Di, J. F. Samuels, Y.-J. Cheng, O. J. Bienvenu, I. M. Reti, P. Costa, W. W. Eaton, K. Bandeen-Roche
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- Journal:
- Psychological Medicine / Volume 42 / Issue 3 / March 2012
- Published online by Cambridge University Press:
- 24 August 2011, pp. 657-667
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Background
Studies have criticized the low level of agreement between the various methods of personality disorder (PD) assessment. This is an important issue for research and clinical purposes.
MethodSeven hundred and forty-two participants in the Hopkins Epidemiology of Personality Disorders Study (HEPS) were assessed on two occasions using the Personality Disorder Schedule (PDS) and the International Personality Disorder Examination (IPDE). The concordance between the two diagnostic methods for all DSM-IV PDs was assessed using standard methods and also two item response analytic approaches designed to take account of measurement error: a latent trait-based approach and a generalized estimating equations (GEE)-based approach, with post-hoc adjustment.
ResultsRaw criteria counts, using the intraclass correlation coefficient (ICC), κ and odds ratio (OR), showed poor concordance. The more refined statistical methods showed a moderate to moderately high level of concordance between the methods for most PDs studied. Overall, the PDS produced lower prevalences of traits but higher precision of measurement than the IPDE. Specific criteria within each PD showed varying endorsement thresholds and precision for ascertaining the disorder.
ConclusionsConcordance in the raw measurement of the individual PD criteria between the two clinical methods is lacking. However, based on two statistical methods that adjust for differential endorsement thresholds and measurement error in the assessments, we deduce that the PD constructs themselves can be measured with a moderate degree of confidence regardless of the clinical approach used. This may suggest that the individual criteria for each PD are, in and of themselves, less specific for diagnosis, but as a group the criteria for each PD usefully identify specific PD constructs.
Obsessive–compulsive disorder: subclassification based on co-morbidity
- G. Nestadt, C. Z. Di, M. A. Riddle, M. A. Grados, B. D. Greenberg, A. J. Fyer, J. T. McCracken, S. L. Rauch, D. L. Murphy, S. A. Rasmussen, B. Cullen, A. Pinto, J. A. Knowles, J. Piacentini, D. L. Pauls, O. J. Bienvenu, Y. Wang, K. Y. Liang, J. F. Samuels, K. Bandeen Roche
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- Journal:
- Psychological Medicine / Volume 39 / Issue 9 / September 2009
- Published online by Cambridge University Press:
- 02 December 2008, pp. 1491-1501
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Background
Obsessive–compulsive disorder (OCD) is probably an etiologically heterogeneous condition. Many patients manifest other psychiatric syndromes. This study investigated the relationship between OCD and co-morbid conditions to identify subtypes.
MethodSeven hundred and six individuals with OCD were assessed in the OCD Collaborative Genetics Study (OCGS). Multi-level latent class analysis was conducted based on the presence of eight co-morbid psychiatric conditions [generalized anxiety disorder (GAD), major depression, panic disorder (PD), separation anxiety disorder (SAD), tics, mania, somatization disorders (Som) and grooming disorders (GrD)]. The relationship of the derived classes to specific clinical characteristics was investigated.
ResultsTwo and three classes of OCD syndromes emerge from the analyses. The two-class solution describes lesser and greater co-morbidity classes and the more descriptive three-class solution is characterized by: (1) an OCD simplex class, in which major depressive disorder (MDD) is the most frequent additional disorder; (2) an OCD co-morbid tic-related class, in which tics are prominent and affective syndromes are considerably rarer; and (3) an OCD co-morbid affective-related class in which PD and affective syndromes are highly represented. The OCD co-morbid tic-related class is predominantly male and characterized by high conscientiousness. The OCD co-morbid affective-related class is predominantly female, has a young age at onset, obsessive–compulsive personality disorder (OCPD) features, high scores on the ‘taboo’ factor of OCD symptoms, and low conscientiousness.
ConclusionsOCD can be classified into three classes based on co-morbidity. Membership within a class is differentially associated with other clinical characteristics. These classes, if replicated, should have important implications for research and clinical endeavors.