Date of Award
2007
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Psychology
Abstract
The heterogeneity of schizophrenia and how best to delineate subtypes has been a problem since schizophrenia was first recognized. Limitations with the current subtypes of schizophrenia include low temporal stability, poor interrater reliability, lack of support for validity, and frequent use of the "undifferentiated" subtype. As an alternative, researchers have proposed dimensional models for subclassification of schizophrenia. These include Crow's Type I/Type II (positive symptoms/negative symptoms), Nicholson and Neufeld's severity of disorder/severity of symptoms model, the three dimension model (negative, disorganized, psychotic) proposed in the DSM-IV, as well as lesser-known four and five dimension models. One important criterion for evaluating proposed changes in classification is clinical utility. The present study compared the interrater reliability and clinical utility of the current categorical subtyping of schizophrenia to the proposed dimensional models. Practicing psychologists read four case vignettes (two prototypic, two nonprototypic) depicting an individual with schizophrenia. Half of the psychologists were asked to diagnose the case based on the current categorical model, while the others used the proposed dimensional models. Clinicians rated confidence in their diagnostic ratings, as well as the clinical utility of each of the models for case conceptualization, professional communication, and treatment planning. Interrater reliability of the categorical and dimensional diagnoses was assessed. It was hypothesized that interrater reliability would be higher for dimensional models, and that ratings of clinical utility would be higher for the categorical model, but that there would be a significant interaction with case prototypicality. Among the dimensional models, the model proposed to in the DSM-IV appendix was expected to perform the best. In general, these hypotheses were not supported. The five factor model proposed by Toomey et al. performed the strongest of the dimensional models. Reasons for these findings, strengths and limitations of this study, implications, and directions for future research are discussed.
Recommended Citation
Hasenwinkel, Megan A., "The Clinical Utility Of Categorical And Dimensional Subclassification Of Schizophrenia: An Investigation Using Prototypic And Nonprototypic Cases" (2007). All-Inclusive List of Electronic Theses and Dissertations. 1072.
https://scholars.indianastate.edu/etds/1072