Diagnostic Criteria, Psychological Tests, and Ratings Scales: Extending the History

Abstract

Diagnostic Criteria, Psychological Tests, and Ratings Scales: Extending the History Peter Zachar, PhD (bio) Le moigne narrates a history of the development of psychiatric ratings scales as hybrids between psychological tests and diagnostic categories. In his telling, psychological tests seek to quantify population-based traits on which every person has a position and which tend to be conceptualized as being stable. Personality traits are often conceptualized as dispositions. Diagnostic categories represent not trait-like properties of populations but episodic states consisting of clusters of symptoms experienced by individuals with disorders. Ratings, scales, he notes, are hybrids between the two. They are used to quantify psychiatric symptom clusters so that change over time can be measured. Le Moigne argues that these distinctions were initially suggested during the development of measures that could assess outcomes in psychopharmacological treatment studies. With respect to depression, Le Moigne writes that in the 1970s and 1980s something akin to depressive personality was reconceptualized as a temperament. A key move, somewhat reflective of Kraepelin’s notion of a depressive temperament, was to view a dysthymic temperament as both a predisposing factor and an attenuated form of depression. Thus, an episodic state commandeered the predisposing–dispositional role that was assigned to stable personality traits. This conceptual shift allowed test-like ratings scales to be seen as useful for quantifying not just stable traits, but salient features of episodic states that are potentially subject to change in response to interventions. To put it another way, in the development of a psychological test, one goal is to have high test-retest reliability (i.e., stability of measurement). With rating scales used to measure change, one wants the scores to not be as stable; ideally the scores on the later assessments will be lower. According to Le Moigne, when dysthymia was subsequently placed on axis I of the Diagnostic and Statistical Manual of Mental Disorders (DSM)-III (as a syndrome) and segregated from personality disorders which were placed on axis II, personality traits were evicted from the conceptualization of depressive disorders. One perennial feature of psychiatry and psychology is that even if an older idea is superseded [End Page 253] in the view of some thinkers, it can still attract adherents. Indeed, interest in understanding a relationship between personality and attenuated states did not fully disappear. For example, based on research in genetics, the schizophrenia spectrum concept included not only schizophrenia, but also milder conditions such that were conceptualized as personality disorders; that is, schizotypal personality disorder and paranoid personality disorder (Kety, Rosenthal, Wender, & Schulsinger, 1971). During the development of the DSM-IV, some people wanted to add depressive personality disorder to the manual (Phillips, Hirschfeld, Shea, & Gunderson, 1995). It seems to have become a territorial dispute between mood disorder specialists and personality disorder specialists The mood disorders specialists challenged the personality disorder specialists to differentiate depressive personality disorder from early onset, chronic dysthymia. They were able to do so by using criteria such as critical, blaming, and derogatory toward self. After the mood disorders work group proposed incorporating some of those criteria into a revised criteria set for dysthymia, the two sets overlapped. The result was the old criteria for dysthymia were printed in DSM-IV and criteria for depressive personality disorder and the revised criteria for dysthymia were both placed in the appendix. In the DSM-5, Axis II was eliminated and personality disorders were placed alongside all the syndromic symptom clusters at the same level. Even so, interest in attenuated presentations as personality-related lingered still. During the development of the DSM-5 there was some thought to using diagnostic spectra as a meta-structure for organizing the manual (Andrews et al., 2009). One idea was to move some personality disorders into a best fitting spectrum, akin to attenuated forms. This did occur with schizotypal personality disorder which is both in the DSM-5 chapter on schizophrenia and in the chapter on personality disorder. In the schizophrenia chapter it is positioned as the earliest emerging disorder on the spectrum. There was also some interest in grouping avoidant personality disorder with the anxiety disorders, but the evidence supporting such a change was not available. These issues may...