FORMACION DE LA ESTRUCTURA MILITAR.

This thesis, as far as I am aware, is the first detailed philosophical investigation of the explanatory functions of psychiatric diagnoses in the context of clinical practice. While I hope to contribute novel insights into the roles and uses of diagnoses in medicine and psychiatry, I concede that my discussion looks at just one aspect of diagnosis from a fairly narrow disciplinary perspective. Specifically, it examines the diagnosis as an explanatory hypothesis about the patient’s clinical presentation through the lens of analytic philosophy of science. As such, it must be made clear from the outset that my discussion is not intended to offer a comprehensive treatment of the many other interesting and important issues concerning diagnosis, to some of which I alluded at the beginning of §1.2.2. Three of these issues warrant special mention here due to the prominent positions they occupy in the literature on diagnosis in the philosophy of psychiatry and the philosophy of medicine.

The first issue of note concerns the concept of disorder. The question here is what demarcates disorder qua medical problem from other kinds of problem, such as moral and social problems, or indeed from normal health. Interestingly, this debate is also partly inspired by Szasz’s arguments in “The Myth of Mental Illness” (1960). As noted in §1.2.1, Szasz presents his arguments as undermining the status of psychiatry as a medical

discipline. Mental illnesses, he argues, are not genuine disorders, but “problems in living”. Since Szasz initially presented his arguments, numerous theorists have offered

philosophical accounts of disorder, with psychiatric disorders often featuring at the centre of the discussion. In reply to Szasz, the psychiatrist Robert Kendell (1975) defends psychiatry as a medical discipline by suggesting a naturalistic account of disorder based on reduced life expectancy and fertility. A more sophisticated naturalistic account of disorder is offered by the philosopher Christopher Boorse (1977), who argues that disorder is a substandard statistical deviation from normal biological function. Perhaps

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one of the most influential philosophical accounts of disorder is Jerome Wakefield’s (1992) harmful dysfunction analysis, according to which a condition’s disorder status is not determined solely by a factual claim about the presence of biological dysfunction, but also requires an evaluative judgement that the condition is harmful. Other normative accounts of disorder include those based on action failure (Fulford, 1989) and on flourishing (Megone, 1998). In more recent years, philosophers have explored more nuanced and pluralistic discussions of disorder that depart from the accounts based on single criteria (Cooper, 2005; Bolton, 2008). There have also been more focused discussions regarding whether or not particular conditions should be considered disorders, including grief (Wilkinson, 2000), ageing (Schramme, 2013), attention-deficit hyperactivity disorder (Saul, 2014), and obesity (Hoffman, 2016).

The problem of demarcation between disorder and non-disorder has been raised in relation to diagnostic validity. Wakefield (1992), for instance, suggests that a diagnostic category is valid if it discerns genuine cases of disorder from cases of non-disorder. However, whether or not a diagnostic category is valid in this sense is a different issue from whether or not it serves as an explanation of a set of symptoms. Of course, I concede that the two issues are related, as a diagnostic category’s lack of explanatory value might provide a reason to suspect that the condition denoted by the category should not be considered a genuine disorder. Nonetheless, disorder status and

explanatory function can come apart, and so are not necessarily connected. For example, the category of menopause can be invoked to explain a woman’s hot flushes, reduced libido, and cessation of menstruation, but it does not follow from this explanation that the condition denoted by the category is a medical disorder. Therefore, once one has established whether or not a given diagnosis serves as an explanation of a set of symptoms, whether or not the condition it denotes should be considered a disorder remains a further question. Addressing this further question would require commitment

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to a particular account of disorder, which is beyond the intended scope of my investigation.

The second issue of note concerns the roles of values in diagnosis. Once again, the debate can be traced back to Szasz (1960), who argues that mental illnesses are not genuine medical disorders, because they are characterised by deviations from social and moral norms. As noted above, some theorists responded to Szasz by suggesting accounts of psychiatric disorder that do not invoke values (Kendell, 1975; Boorse, 1977). Other theorists, including Bill Fulford (1989), John Sadler (2005), and Tim Thornton (2007), acknowledge that psychiatric diagnoses are value-laden, but argue that this value- ladenness does not necessarily undermine their scientific validity. Sadler proposes that values are involved at every level in psychiatric diagnosis, including the diagnostic criteria, the stereotype of the condition, the judgement about its disorder status, and the very enterprise of constructing a classification system. I fully accept that values are involved in diagnosis and that understanding their roles is important. However, a comprehensive analysis of values in psychiatric diagnoses is not necessary for my investigation into whether or not psychiatric diagnoses function as explanations of symptoms. The two issues can, for the most part, be kept apart, although I concede that they may be contingently related. As such, I discuss value-ladenness in this thesis only where it is directly relevant to the question of the explanatory role of a diagnosis.

The third issue of note concerns the relation of diagnosis to evidence-based medicine. This is an important topic, particularly given that evidence-based medicine has been portrayed as being a new and dominant paradigm in clinical medicine (Evidence- Based Medicine Working Group, 1992). Accordingly, in recent years, the philosophy of medicine literature has swelled with highly welcome critical discussions of problems in evidence-based medicine, including the hierarchy of study designs, the epistemic purpose of randomisation, the role of tacit knowledge in clinical judgement, and the evidential

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value of mechanistic reasoning (Bluhm, 2005; Thornton, 2007; Worrall, 2007; Bird, 2011; Howick, 2011; Andersen, 2012). The topics of diagnosis and causal explanation are certainly related to the topic of evidence-based medicine. For example, populations for statistical trials are usually defined in part by diagnostic criteria, and there is an active debate regarding the respective roles of statistical evidence for correlations and

mechanistic causal explanations in guiding clinical decisions (Clarke et al., 2014: p. 346). However, for the specific purposes of this thesis, the discussion of whether psychiatric diagnoses explain symptoms and the discussion of how diagnoses relate to evidence- based medicine can, to a significant degree, be kept apart. Hence, while I do suggest that diagnoses and the explanations they provide can help to inform predictions and guide therapeutic interventions, I do not intend in this thesis to examine precisely how, or indeed whether, such epistemic resources can complement an evidence-based medicine approach.

In summary, the above mentioned issues can be seen as being orthogonal to, rather than challenging, the analysis I provide in this thesis. Of course, there are areas where the topic of my investigation and these other issues meet, and I would be delighted if it turns out that my discussion helps to shed new light on these issues. However, given the specific focus of my investigation, I do not intend to explore these areas in detail in the current thesis.