Try explaining mental illness without alluding to its nature in some way. Its impossible. You might, rather foolishly like Guze, say its nothing more than a brain disease, or perhaps argue for some form of Freudian psychological malfunctioning or grand scale failing on the part of society. But in each instance you are assuming a particular view on the nature of the mind and mental illness. What's more is that such a view constrains the kinds of methodology that you can use. If mental illness is a brain disorder, why bother with psychology? Go straight to the molecules! If its the subconscious torments of sexual frustration, sod the CBT and whack out the Rorschach cards. You get the point. Ontology constrains methodology and treatment for that matter.
An ontology in the sense that I am using it is what Kuhn termed a paradigm; the overriding theory about the existence of nature within which your hypotheses and explanations exist. Such paradigms change and arguably lead to better more parsimonious explanations, the shift from Newtonian physics to Einstein's theory of relativity being a common example.
But there's a problem for psychiatry. The nature of the mind is a slippery one and psychiatry hasn't quite decided what exactly it is yet. This isn't the fault of psychiatrists, it simply reflects the complexity of the subject at hand. Historically, psychiatry has been grounded in a variety of paradigms from biological reductionism to Freudian psychoanalysis to the biopsychosocial model. All which have failed to offer a suitable ontology in which to explain, investigate or treat the mind and mental illness (see here).
It is interesting then, that in light of the failings of previous theories, psychiatry seems to be attempting to subvert the problem of ontology by appealing to American pragmatist philosophies of Pierce and Dewey, as Brendel explains:
Pragmatism, as I am using the term in the current context, refers to the theory that psychiatric explanations are ‘‘true’’ only insofar as they promote beneficial real-world results for individuals with mental illnesses. As a practical discipline, psychiatry is concerned more with its methodology than its ontology: by adopting a pragmatic position on explanatory models, psychiatrists do not necessarily commit themselves to a particular view on the underlying structure of the universe. Psychiatric explanations are coherent and plausible insofar as they are pragmatically useful and empirically testable in clinical settings.
One such feature of the pragmatist approach that has emerged is the application of Karl Jaspers’ Methodological Pluralism. He explains:
Instead of forcing the subject-matter into a strait-jacket of systematic theory, I try to discriminate between the different research methods, points of view and various approaches, so as to bring them into clearer focus and show the diversity of psychopathological studies. No theory or viewpoint is ignored. I try to grasp each different view of the whole and give it place according to its significance and limitations…We obtain our facts only by using a particular method. Between fact and method no sharp line can be drawn. The one exists through the other. Therefore a classification according to the method used is also a factual classification of what is, as it is for us.
Speaking to a psychiatrist recently, he informs me this seems to be the fashionable take on things for those in research and in practice. In other words, we should not concern ourselves with the difficulty (and it is very difficult) of explaining the ultimate nature of mind and mental illness but rather use all the available theories and research, picking and choosing based on their strengths and limitations, constrained by evidence based medicine.
At first glance this seems a decent suggestion and is given further stability through Kendler's argument for levels of explanation. We can explain the same phenomenon at various different levels becoming more and more abstract from the levels of particles to chemicals to biology to systems etc. Depending on what we want to explain we have to choose the correct level. It would not, for example, be particularly useful to explain the heart at the level of particle physics.
Such an approach is a sensible temporary solution to guide scientific investigation into mental illness in the absence of an overriding ontology in order to avoid the dogmatism of past paradigms such as biological reductionism. The problem, however is that it must be recognised that it can only ever be a temporary solution, since the pragmatist pluralist paradigm offers no ontology of mind to guide methodology. Whilst research can be understood within the particular level of explanation, constrained by that particular ontology, pluralism does not offer a means by which we choose or reject certain levels or indeed integrate the different levels. As such we are simply stuck with the same kind of eclecticism offered by the biopsychosocial model, by which we have scattered and often incompatible theories and research.
Pluralism is correct in emphasising the need for a focus on the different levels of explanation available but fails in its assumption that we do not need a unifying theory to tie it all together. In order to truly understand and treat mental illness we need a unified theory of mental illness to guide and constrain the kind of integrative methodology the pluralist approach entails.
Brendel, David H. "Reductionism, eclecticism, and pragmatism in psychiatry: The dialectic of clinical explanation." The Journal of medicine and philosophy 28.5-6 (2003): 563-580.
Ghaemi, Seyyed Nassir. "Paradigms of psychiatry: eclecticism and its discontents." Current opinion in psychiatry 19.6 (2006): 619-624.
Guze, Samuel B. "Biological psychiatry: is there any other kind." Psychological Medicine 19.2 (1989): 315-323.
Kendler, Kenneth S. "Toward a philosophical structure for psychiatry." American Journal of Psychiatry 162.3 (2005): 433-440.
Kuhn, Thomas S. The structure of scientific revolutions. Vol. 2. University of Chicago press, 1996.
Jaspers, Karl. General psychopathology. Vol. 2. Johns Hopkins University Press, 1997.