Another Scientific American Article on DSM-V: Is This A Step Too Far?
I came across this Scientific American Blog article via a Scientific American tweet (the Scientific American tweets reach over 356,000 people). The article is titled ‘Trouble at the Heart of Psychiatry’s Revised Rule Book’. The author University of Toronto History Professor Edward Shorter challenges the Diagnostic Statistic Manual classifications of three common mental illnesses – Major Depressive Disorder, Bipolar Disorder and Schizophrenia. I will address the author’s arguments against each in turn. However before doing so it is necessary to explain what a diagnostic system means and how it relates to science.
A diagnostic system is a system for classifying illnesses. DSM-V is the American Psychiatric Association’s classification system for mental illnesses. Psychiatry is a branch of Medicine which in turn is a branch of Science. Nevertheless as well as being a branch of Science, Psychiatry also involves the application of Science which is Technology. Let us look at some definitions of technology.
Dictionary.com: ‘The application of practical sciences to industry or commerce‘
Merriam-Webster: ‘The practical application of knowledge especially in a particular area‘
Oxford Dictionaries: ‘The application of scientific knowledge for practical purposes, especially in industry‘
The above definitions support the understanding of technology as the practical application of a body of knowledge including scientific knowledge. Diagnostic systems are a guide to aid practitioners in the practical application of a body of scientific knowledge and can therefore be described as a technology which complements a corresponding body of scientific knowledge*. This relationship is illustrated in the diagram below.
Once Psychiatry research and diagnostic systems are conceptualised in this way, it becomes much easier to understand the issues that Professor Shorter raises in his article. Throughout the article Shorter refers to diagnostic categories as artifacts and presumably is implying that they are errors. I will now address the arguments raised by Professor Shorter against 3 common mental illnesses and demonstrate that his arguments are erroneous.
1. Major Depressive Disorder. The author’s argument against Major Depression is that it was constructed as a political maneouvre which resulted in the amalgamation of two distinct types of depression which he recommends the authors of DSM-V should reconsider. I will address the two parts of the argument.
a. Shorter argues that the current diagnosis of Major Depression contains an amalgamation of two distinct illnesses – Melancholia and Non-Melancholia which are also identified as Endogenous and Reactive Depression. This distinction certainly is possible and it would be clinically useful. There is an underlying body of scientific knowledge which supports the construct of an illness referred to as Depression. There is also evidence to support Melancholic and Non-Melancholic forms of Depression. Interestingly though, Shorter doesn’t cite the relevant literature to support his case.
However there is also evidence against using this distinction. For instance Reactive Depression is considered to be a response to an external life event in contrast with Endogenous (Melancholic) Depression. However Bebbington and colleagues found in their study that cases of Endogenous Depression were just as likely to be preceded by life events as were cases of Reactive Depression (Bebbington et al, 1988). Furthermore Brown and Harris in landmark research characterised the relationship between chronic stressors and the onset of Depression (Brown and Harris, 1978). This research led to the creation of a vulnerability model of Depression. In this model a person will have a vulnerability to developing Depression which is then precipitated by life events.
We can now see that as well as a case for Melancholic and Non-Melancholic Depression there is a body of scientific knowledge which does not support this distinction. This is the science but what about the technology? The DSM-V committee must meet and use the body of scientific knowledge to make practical decisions about the diagnostic categories that will be used. Even at this stage, reliability data for diagnostic categories is just emerging from recent studies which the committee will consider in their deliberations. The emphasis though is on deciding what use to make of this body of scientific knowledge. These decisions are made within expert committees and are decisions made within the profession although incorporating expertise from other disciplines. From the discussion above, this is the application of scientific knowledge or technology which is distinct from the scientific process.
b. Shorter argues that Major Depression combines two distinct illnesses as a ‘political maneouvre’ and attributes this to an individual. However the same combination of Melancholic and Non-Melancholic features are also incorporated in the Depression criteria in the World Health Organisation’s ICD-10 Classification of Mental and Behavioural Disorders which is another popular diagnostic system.
In conclusion, Shorter recognises that the body of scientific knowledge supports the case for a Melancholic/Non-Melancholic distinction. That is the science. From there though, Shorter moves onto the technology and disagrees with the decision made by the expert consensus body when applying their knowledge of the scientific literature. In other words, Shorter who is not a member of the profession, disagrees with the decision taken by an expert consensus group of professionals to determine the contents of their profession’s diagnostic system. This is a separate matter from the science. The profession is backed up by a body of science which they have referenced in arriving at the diagnostic category. This body of science is the area that Shorter should have addressed but avoided citing at all.
In his discussion of Schizophrenia, after referring to this as an artifact he then proceeds to state that
3. Bipolar Disorder. Shorter refers to Bipolar Disorder as
Goodwin and Jamison concluded in their assessment of the research literature that Bipolar Depression and Unipolar Depression were indeed distinct but restricted their analysis to a comparison of Bipolar I Depression and Unipolar Depression (Goodwin and Jamison, 2007). Here they state that
‘The most widely replicated studies point to a picture of the bipolar-I depressed patient as having more mood lability, psychotic features, psychomotor retardation and comorbid substance abuse. In contrast, the typical unipolar patient in these studies had more anxiety, agitation, insomnia, physical complaints, anorexia and weight loss‘ (Goodwin and Jamison, 2007)
Goodwin and Jamison cite a considerable body of research literature to support their conclusions. Shorter does not comment on the distinction between Bipolar I and II Depression or even on Hypomania and Mania. With regards to these being ‘natural disease entities’ it is difficult to know what exactly Shorter means by this. For instance if he means that there is an illness which is independent of socialcultural factors then there is an abundance of evidence of manic illnesses occurring throughout history (when referring to Bipolar Depression in which the Depression may follow on from an episode of Mania). As an example in 1812 Rush writes
‘Its premonitory signs are, watchfulness, high or low spirits, great rapidity of thought, and eccentricity in conversation, and conduct; sometimes pathetic expressions of horror, excited by the apprehensions of approaching madness; terrifying or distressing dreams; great irritability of temper; jealousy, instability in all pursuits; unusual acts of extravagance, manifested by the purchases of houses, and certain expensive and unnecessary articles of furniture, and hostility to relations and friends‘ (Rush, 1812)
Other descriptions date back as far as Cappadocia in 150 AD (Jellife, 1931) and continue into the present detailing the common characteristics of manic episodes. Shorter then goes on to suggest that
Brown, G.W and Harris, T.O. Social Origins of Depression. Tavistock. London. 1978.
Goodwin F K and Jamison K R. Manic-Depressive Illness. Bipolar Disorders and Recurrent Depression. Oxford University Press. 2007. Chapter 1. p 17.
Jellife, S.E. Some historical phases of the manic-depressive synthesis. Research Publications Association for Research in Nervous and Mental Diseases. 11. 3-47. 1931.
Rush B. Medical Inquiries and Observations upon the Disease of the Mind. Philadelphia:Kimber and Richardson. 1812
* This might be counterintuitive but one way to help think about it is to ask two questions
1. What new knowledge is produced as a result of creating a diagnostic category or refining the diagnostic category?
2. What is the process being used to create a new category or refine an old one and how does this compare with the process of doing scientific research?
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