title: An item response theory integration of normal and abnormal personality scales.
abstract: The Diagnostic and Statistical Manual of Mental Disorders (DSM–IV–TR) currently conceptualizes personality disorders (PDs) as categorical syndromes that are distinct from normal personality. However, an alternative dimensional viewpoint is that PDs are maladaptive expressions of general personality traits. The dimensional perspective postulates that personality pathology exists at a more extreme level of the latent trait than does general personality. This hypothesis was examined using item response theory analyses comparing scales from two personality pathology instruments—the Dimensional Assessment of Personality Pathology-Basic Questionnaire (DAPP-BQ; Livesley & Jackson, in press) and the Schedule for Nonadaptive and Adaptive Personality (SNAP; Clark, 1993; Clark, Simms, Wu, & Casillas, in press)—with scales from an instrument designed to assess normal range personality, the NEO Personality Inventory–Revised (NEO PI-R; Costa & McCrae, 1992). The results indicate that respective scales from these instruments assess shared latent constructs, with the NEO PI-R providing more information at the lower (normal) range and the DAPP-BQ and SNAP providing more information at the higher (abnormal) range. Nevertheless, the results also demonstrated substantial overlap in coverage. Implications of the findings are discussed with respect to the study and development of items that would provide specific discriminations along underlying trait continua.
authors.affiliation: Department of Psychiatry, Yale University School of Medicine, USA. douglas.samuel@yale.edu
authors.forename: Douglas B
authors.initials: DB
authors.lastname: Samuel
authors.forename: Leonard J
authors.initials: LJ
authors.lastname: Simms
authors.forename: Lee Anna
authors.initials: LA
authors.lastname: Clark
authors.forename: W John
authors.initials: WJ
authors.lastname: Livesley
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Widiger
mesh_terms: D000223:Adaptation, Psychological; D000328:Adult; D000704:Analysis of Variance; D003627:Data Interpretation, Statistical; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D008297:Male; D008960:Models, Psychological; D010551:Personality / Q000145:classification*; D010554:Personality Disorders / Q000145:classification / Q000523:psychology*; D010555:Personality Inventory / Q000706:statistics & numerical data; D010556:Personality Tests / Q000706:statistics & numerical data*; D011594:Psychometrics / Q000379:methods*; D011795:Surveys and Questionnaires; D055815:Young Adult
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