The DSM-IV-TR represents a categorical model of abnormality.

The DSM-IV-TR represents a categorical model of abnormality. Some psychologists have suggested that a dimensional model (where behavior exists on a continuum and “abnormal” is simply an extreme form of normal behaviors) may be more accurate. Do you support the categorical approach or the dimensional? Why? Which model (categorical or dimensional) would be of greatest use to clinicians? What about researchers?

DSM has always promoted categorization of personality disorders. This approach entails treating abnormalities of personality as discrete entities through hierarchical structuring. In contrast, the dimensional model treats personality disorders as measurable continua and does not place people in diagnostic categories. Simply put, DSM approach attempts to evaluate the absence or presence of a particular disorder whereas the dimensional model seeks to explore the degree of a particular personality disposition. In my view, clustering of disorders into different classes- a doctrine supported by DSM-IV-TR -is inferior to treating disorders as a continuum and that’s why is support the dimensional model. Another reason, why I disapprove of the DSM-IV-TR approach is that this categorization system prescribes to arbitrary thresholds for diagnosis. As result, you find that sometimes there are heterogeneities, extensive overlaps or co-morbidity within categories. In addition, this approach does not cover the complexities and subtleties of the personality psychopathology.

On the contrary, dimensional model captures important clinical information that the DSM-IV-TR model cannot. In addition, the dimensional model captures clinical heterogeneity and co-morbidity well and gives a more reliable description of all types of patients. It is due to these reasons that I feel dimensional model could be more useful to clinicians than the DSM-IV-TR approach. Another reason why clinicians would rather depend on dimensional model than DSM-IV-TR approach is due to the fact that some patients may have clinically significant traits that are below the threshold of diagnosis and these patients are likely to go untreated if clinicians use the DSM-IV-TR model.

For researchers, I still think the dimensional model could be more useful than the DSM-IV-TR model. This is because unlike, the DSM-IV-TR model, dimensional model provides researchers with room to re-assess personality disorders rather than relying on the categorizations that have been established through the DSM-IV-TR approach. In addition, DSM-IV-TR gives researchers an opportunity to resolve the existing disagreements about the presence or the absence of a particular disorder.