A stone is a stone because it is a stone
The DSM and ICD manuals have both been useful in that they established a common language for research and clinical practice. It was explicitly stated in DSM III that as a starting point there was no underlying assumption that the categories were validated entities (3). Nevertheless it was presumed that a gradual empirical validation of the chosen categories of disorders would eventually come about as research advanced. For the most part this has been unsuccessful (9) – (13). Nevertheless, the categories in the diagnostic manuals have increasingly been used as though they actually represent conditions for which the cause is known. This is perhaps not so strange – «The tendency has always been strong to believe that whatever received a name must be an entity or being, having an independent existence of its own,» said the English philosopher John Stuart Mill (1806 – 73).
The American psychiatrist Steven Hyman describes this as «the problem of reification» (9). That is to say that the diagnoses are increasingly treated as if they were concrete, natural entities, even though they have essentially been purely constructs. The validity of the diagnoses has all along been problematic, that is, how far what is described actually represents something real and «true», something that is grounded in science (14). This problem has gradually become more intrusive as, based on voting, more and more diagnoses have been included.
The last few years have provided us with more knowledge of genetics, neurophysiology, neuropsychological mechanisms and language development. There is an escalating sense of frustration that there is little manifestation of this knowledge in new knowledge of aetiology, the course and the treatment of disorders, and Hyman and others (9) – (13) believe that the existing diagnostic criteria prevent a more comprehensive understanding. To put it another way, psychiatric research takes as its starting point categories of disorder that are based on clinical manifestations of symptoms and signs. This means that one-to-one explanations are sought, even though it is increasingly obvious that these do not exist (11). There is a danger of using circular reasoning: A stone is a stone because it is a stone.
The weaknesses of this type of research are shown by the fact of losing one’s way in descriptions of comprehensive comorbidity, of having problems in delimiting one condition in relation to another and of defining the characteristics of particular diagnoses (9, 11). For example, if one wishes to examine possible causes of obsessive-compulsive disorder and to take as a basis a group of patients with this diagnosis, common causal factors will only reflect that the patients belong to the same diagnosis-related group. Findings which deviate may be ascribed to comorbidity – if you have an obsessive-compulsive disorder, there is a 70 % risk that during the course of your life you will also satisfy the criteria for severe depression; for bipolar disorder it is 10 %. In addition you will have an increased risk for post-traumatic stress disorder and other anxiety disorders (15). If instead it were possible to identify common factors, for example emotional response to loss of control, this would provide a more open approach across existing categories.