Kendell's (Reference Kendell2001) editorial made two mistakes in its reasoning, which led to an unhelpful conclusion. One cannot say that mental and physical illness should be conflated because, irrespective of the balance, mental and physical symptoms are expressed in both. This is insisting that differences in degree are not differences at all. There are indeed many disorders that have both mental and physical expressions. However, to claim that anxiety-related chest pain and myocardial infarction are both physical disorders is to conflate precisely what we wish to distinguish, even if anxiety can cause both. We contrast the terms ‘mental’ and ‘physical’ because the contrast says what we mean, and we have good reason for meaning it. As Kendell himself points out, no alternative has been found.

Proposing that disturbances in bodily function are necessary for psychiatric disorder does not imply that psychiatric disorders are physical disorders. Consider a computer virus. It may exist as a series of electrical states in a computer, a set of statements in a computer language, even a series of thoughts in someone's head, so its existence is not dependent on any physical object. None the less, it may disrupt a computer's function despite there being no physical fault in the machine. It is generally accepted that such arguments show that mental states might themselves be functions (Reference HeilHeil, 1998), and so purely functional psychiatric disorders are quite possible.

These mistakes lead Kendell to suggest that stigma might be reduced if all psychiatric disorders were to be regarded as physical. This makes mental illness literally unspeakable. But not speaking of something true implies an attitude towards it of denial, shame and horror, not acceptance. The concept of mental health and its promotion is currently competing successfully with ‘madness’ in popular culture. By falsely declaring ‘mental’ to be meaningless, the editorial threatens this progress. It may also consign those of our patients who are not sufficiently biological in their pathology to that therapeutic underclass, the ‘worried well’.