DSM – Unfit for Purpose
In some ways, it’s hard to understand what all the hullabaloo with the DSM is about. Allow me to explain. The publication of the DSM-5 has generated spirited debate about different aspects of the diagnostic approach provided by the DSM. The debate has important implications for the way mental health problems are understood and treated.
One perspective that is seldom considered in the debate is whether or not the DSM can fulfill the purpose it was designed for. The query about whether we should diagnose is separate to the matter of whether it is possible to diagnose using the DSM. Even if diagnosis is important and useful, the DSM is not up to the task.
The Diagnostic and Statistical Manual of Mental Disorders published by the American Psychiatric Association (APA) purports to be, first and foremost, a diagnostic manual. Diagnosis, as it is defined in Wikipedia, “is the identification of the nature and cause of anything” (http://en.wikipedia.org/wiki/Diagnosis). It would be reasonable to assume, therefore, that the DSM would assist in identifying the nature and causes of mental disorders. Quite apart from whether or not it is appropriate (or even possible) to diagnose mental disorders is the issue of the DSM’s ability to deliver on what it says it is.
The introduction to the DSM-IV TR explains that “important methodological innovations” (APA, 2000, p. xxvi) were introduced with the DSM-III. One of these innovations was that the new DSM was “a descriptive approach that attempted to be neutral with respect to theories of etiology” (p. xxvi). So, even though diagnosis is the identification of the nature and causes of something, the APA somehow reconciled publishing a diagnostic manual that made no comment on the causes of that which was being diagnosed.
Perhaps it could be argued that despite not being able to offer comment on the causes of mental disorders, the DSM still provides a useful guide to the categorization of mental disorders. Here, advice from the DSM is instructive: “In DSM-IV, there is no assumption that each category of mental disorder is a completely discrete entity with absolute boundaries dividing it from other mental disorders or no mental disorder” (APA, 2000, p. xxxi). So the categories that DSM offers us do not have boundaries demarcating one disorder from another or, indeed, one disorder from no disorder. This is an extraordinary revelation. This means, according to the DSM, that there is no assumption that the category “schizophrenia” has boundaries that separate it from other mental disorders or from not having schizophrenia.
The DSM goes on to say that “there is also no assumption that all individuals described as having the same mental disorder are alike in all important ways” (p. xxxi). It is certainly reasonable to expect some degree of variability in people having the same disorder but surely it is also reasonable to expect that people with the same disorder would be alike “in all important ways.” Should we not expect that people diagnosed with Generalized Anxiety Disorder (for example) would have core common features? The DSM advises that this is not necessary. Perhaps this is because there is no assumption that people assigned to the Generalized Anxiety Disorder category will be different from people allocated to the Social Phobia category nor any assumption that people in these groups should be distinguishable from people with no anxiety.
While a certain amount of intra-group heterogeneity is probably a feature of most systems of nosology the heterogeneity permissible in the DSM is extravagant. Lareau (2012) reports that there are 175 different symptom combinations that all qualify for a diagnosis of posttraumatic stress disorder and, according to Perepletchikova and Kazdin (2005), there are 32,647 symptom patterns that satisfy a diagnosis of conduct disorder.
Defenders of the DSM often suggest that it facilitates communication between mental health professionals by providing a common language. If the common language of DSM, however, uses the same diagnostic terms to refer to people who might not have important features in common, what sort of communication does it enhance? If one clinician advises another clinician that a particular person has been diagnosed with conduct disorder, what common language are they speaking? There is a real possibility that DSM provides an illusion of understanding on the one hand while obfuscating accurate understanding on the other.
The DSM does not explain causes, does not separate those with a disorder from those without, and has no requirement of a core set of common features being necessary for group membership of its categories.
What is the utility, clinical or otherwise, of a diagnostic manual that cannot separate – by its own admission – those with a disorder from those without one? If the DSM will not guide us on distinguishing between the “haves” and the “have nots” of what purpose is it?
Whether diagnosis is important, appropriate, or even possible, the DSM informs us it is not the tool for the job. Early in the manual it advises readers that it is neutral with respect to the cause of disorders, that the categories it offers do not separate different disorders, that it does not discern the presence from the absence of disorder, and that people assigned the same disorder will not necessarily be “alike in all important ways”.
Understanding people and the problems they experience will not arise by allocating them to one or more DSM categories. Useful understanding will emerge when efforts are made to learn about people and their problems in the context of the lives they wish to live. What are the problems being experienced and how do these problems prevent people living a life of their own design? Questions of this ilk are probably explored in many mental health services currently, however, all too frequently the questioning occurs under the shadow of the DSM. Stepping out of this shadow and affording this type of question a central role in mental health service provision will promote more nuanced and more effective way of helping people experiencing psychological distress.
American Psychiatric Association. (2000). The diagnostic and statistical manual of mental disorders. Fourth edition. Text revision. Arlington, VA: American Psychiatric Association.
Lareau, C. R. (2012). Posttraumatic stress disorder and acute stress disorder. In D. Faust (Ed.), Coping with psychiatric and psychological testimony (pp. 610-635). Oxford: Oxford University Press.
Perepletchikova, F., & Kazdin, A. E. (2005). Oppositional defiant disorder and conduct disorder. In K. Cheng and K. M. Myers (Eds.), Child and adolescent psychiatry the essentials (pp. 73-88). Philadelphia, PA: Lippincott Williams & Wilkins.