Tuesday, 29 April 2014

The Definition of Mental Disorder: Evolving but Dysfunctional?

Natalie Banner
I'm a former research fellow in the philosophy of psychiatry at King’s College London, now working in policy at the Wellcome Trust. In my academic research the definition of mental disorder was a frequent, seemingly intractable problem and in this post I want to query whether a definition may be needed at all.

In a previous post, Rachel Cooper talked about the potential advantages of the ambiguity offered by the DSM-5 definition of mental disorder. I very much agree that the stipulation of necessary and sufficient conditions is unlikely to succeed in mapping such complex messy and controversial phenomena as “mental disorders”. However, I am unsure whether in this particular case an ambiguous definition is quite so benign as Rachel implies. It is true that few clinicians will pay attention to the introductory text, being more concerned with the features of the diagnosis they are dealing with at any particular moment, but this is not to say that the definition provided is not an important and influential part of the manual.

As a colleague Rachel Bingham and I suggested in a recent paper, a significant driver for attempting to define mental disorder emerged in the scientific and political fallout of the declassification of homosexuality from the DSM in 1973. The move to declassify came about through civil rights activism that highlighted, among other things, the lack of scientifically credible evidence to support the claim that homosexuality was a mental disorder: psychodynamically-driven theories assuming the pathological status of homosexuality were undermined once the existence of happy, functioning, well-adjusted gay individuals was acknowledged. Against this backdrop, it is understandable why the effort to seek out a clear cut definition of mental disorder, and thus clarify the domain of psychiatry, was so important. If psychiatry was to avoid being used as a tool of social control to pathologise behaviours simply seen as abnormal by society, it had better be able to delineate what counts as a mental disorder from what doesn’t.

Fast forward to today, and the DSM-5 definition attempts to bridge the ‘values-out’ versus ‘values-in’ camps with a broad definition subject to wide interpretation. This has its uses when the jury is still out, certainly, but we ought to be alert to the potential dangers of ambiguity in the wording of any working definition that is supported by the influential DSM. This is particularly so given concerns over the inflation of psychiatric categories and the perceived risks of pathologising what are essentially normal human behaviours. Only last month the diagnosis of Attention Deficit Hyperactivity Disorder was called into question by a leader in the field, and there has long been controversy over whether the DSM-5 criteria count the experience of bereavement as “major depression.” Sensible discretion in the application of the definition may be urged (akin to Rachel’s example from HLA Hart), but there are many competing interests at stake in diagnostic classification that may not in practice reflect the deliberations of a objective, dispassionate and sensible judge.

If one of the reasons for seeking a definition of mental disorder in the first place was to prevent psychiatry from over-reaching its boundaries, I’d argue that it could be better not to attempt to define the overarching category of “mental disorder” at all. This would be preferable to providing a scientific gloss to ambiguous terms that could potentially encompass far more behaviours, conditions and experiences than the authors of the definition ever intended.


  1. I suspect that we need better definitions - and the catch all criteria “the disturbance causes clinically significant distress or impairment in social, occupational, or other important areas of functioning" (DSM 5 intro) might be enough..... So, for example, whilst 'hearing voices' is a first rank symptom of schizophrenia if I'm not distressed or otherwise 'impaired' by it then I'm not ill. Although, I guess 'distress' or other problems could arise from social stigma (and for no other reason) and/or knowing that it is a symptom - in which case my 'illness' would be iatrogenic.....

  2. In my post I didn’t mean to suggest that the ambiguous definition of mental disorder included in the DSM-5 was “benign”, but only that it was strategically useful to the APA. Whether a more precise definition, or no definition, might offer better protection against psychiatry over-reaching itself is another matter. Actually I think it would be far better (not for the APA, but for those of us who might end up being diagnosed) if the DSM was clear that a diagnosis could only be made if a patient is harmed by their condition.

    Whether one thinks that disorders necessarily cause harm (as per DSM-III-R and DSM-IV), or are merely “often associated” with harm (as per DSM-5) matters as it makes a difference to who might be diagnosed. Some people have many of the “symptoms” of mental disorder but find these unproblematic. Consider Asperger’s Disorder (high-functioning Autistic Spectrum Disorder under DSM-5), for example. There are some people who meet all the diagnostic criteria - they don’t “get” the nuances of social interaction, their style of speech is odd, their interests unusual, and so on – but they are not unhappy or impaired. Should such people be diagnosed as having a mental disorder, or should they just be considered different? If mental disorder by definition causes harm, then a flourishing individual cannot be diagnosed. They are simply different. In contrast, if mental disorder is merely “typically associated” with harm, then the happy person with Asperger’s can be given a diagnosis. Many other cases raise similar issues: consider happy and high-functioning voice-hearers; people who have a low I.Q. on tests, but who have no problems in their everyday life; those who have a very low sex-drive but don’t care.

    So far, in practice, the new definition of disorder included in DSM-5 will have had little impact on the actual contents of the classification. The definition was developed far too late in the revisionary process to have influenced decisions about the contents the classification. Looking to the future, however, the change to the definition included in the DSM should be a real concern for those who think that disorders are necessarily harmful. Currently it remains the case that many of the individual sets of diagnostic criteria included in the DSM include a requirement that the particular disorder can only be diagnosed if it produces harm. The exact wording varies but generally requires that “the disturbance causes clinically significant distress or impairment in social, occupational, or important areas of functioning”. The DSM-IV had many similar criteria and these have generally been maintained in the DSM-5. The difference is that, with the change in the definition of mental disorder, there is no longer a robust rationale for the inclusion of the harm-related criterion in the individual sets of diagnostic criteria. Previously, this criterion was included as a reminder to clinicians that the diagnosis should only be made if harm was caused because the definition of disorder required harm, i.e the rationale was conceptual. With the change in the definition, there is nothing to guard against some future edition of the DSM deciding to ditch the idea that disorders have to cause harm altogether. The change to the definition of disorder included in the DSM means that the notion that disorders necessarily cause harm is under threat. This should be cause for concern because the criterion that requires that disorders cause harm is crucial to prevent some of those who are merely different from being diagnosed.


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