Jim van Os provides an excellent summary of why many clinicians and researchers (especially the latter) have become frustrated with the imprecision of the term schizophrenia. Among scientists, calls to abandon the diagnosis have sounded for more than 25 years and will probably eventually be heeded. Few scientists would bet that it will retain its currency another century from now. However, there is a deep philosophical tangle involved in the headline claim that “schizophrenia” doesn’t exist.

Some who oppose the label of schizophrenia have made their case by comparing it with phlogiston, a hypothetical substance which was posited in 1697 to explain the fact that some materials combust. Despite an increasing array of inconvenient scientific results (some things gained mass when they burned, rather than losing it as predicted), phlogiston theory stuck around for over 100 years, until it was supplanted by Lavoisier’s oxygen (which could account more elegantly for existing results) in 1789.

In one sense phlogiston did not exist, but did the term successfully refer to something? Some philosophers of science have suggested it did; after all there was a substance present (oxygen) which helped combustible materials to burn. Under this view, scientists who used the term phlogiston were talking about something real.

The same might be said about schizophrenia. The diagnosis is doubtless applied to a range of people with many different problems. When these are more fully understood, they can be carved away from schizophrenia to provide an accurate diagnosis. One recent example is NMDA receptor encephalitis, a brain disease which can give rise to the symptoms of (and thus get diagnosed as) schizophrenia. This raises the possibility that many of those diagnosed with schizophrenia are suffering from currently unidentified diseases; unknown for now but real, and giving rise to the behavior which meets the DSM and ICD schizophrenia criteria.

If a patient has an unidentified illness that causes them to meet diagnostic criteria for schizophrenia; they don’t really have schizophrenia, unless we take “schizophrenia” to refer to the unnamed illness they do have. This probably isn’t what most people mean when they say “schizophrenia,” but as van Os points out the term has a variety of referents. Officially, it is “just a classification” but some sources describe it as “a chronic brain disorder,” others as a “neurodevelopmental disorder,” and so on.

In his semi-autobiographical book on the topic, Peter Chadwick describes his reluctance to dispense with schizophrenia in the absence of a better alternative: “There was no doubt I was suffering to a degree far beyond anything I previously had ever known […] and, it seems to me, I was suffering with something!” Chadwick calls that thing schizophrenia, despite his awareness that it is not a unitary illness. This is not dishonesty or false consciousness; schizophrenia is a substantive socio-medical phenomenon, a social construct built up around a real core of experience. Few would argue that it should not one day be replaced, but it is overly simplistic to say that it does not exist.

Huw Green is a PhD candidate and trainee clinical psychologist at the Graduate Center and City College of the City University of New York. You can follow him on Twitter @Huwtube

Competing interests: I have read and understood BMJ policy on declaration of interests and declare none.