earlier post), I am supporting the campaign to abolish psychiatric diagnostic systems. This campaign 'No more psychiatric labels' gives its rationale on its website.
The World Health Organisation started classifying the causes of death in the International Classification of Diseases (ICD). In the sixth revision it extended its classification to causes of morbidity as well as mortality and a chapter was added for psychiatric disorders (which don't cause death as such). The americans have always run a parallel DSM system. ICD-9 and DSM-II were essentially the same.
Criticism of psychiatric diagnosis led to the DSM-III revision, which attempted to define psychiatric disorders using operational criteria. Although it may have been technically atheoretical in its approach, it encouraged a biological understanding of mental illness as due to brain disorder. The misguided hope has been that reliable diagnoses will equate with standardised biological tests developed by advancing neuroscience (eg. see blog by Allen Frances, who has also been critical of DSM-5 because of its potential expansion of the boundaries of psychiatric diagnoses). DSM-IV abolished the distinction between organic and functional disorders as they are all seen as brain disorders (see previous post).
There were of course diagnostic systems before ICD-6 and DSM-I, but it is the authority attached to diagnostic descriptions since DSM-III that causes problems. However important classification may be for scientific communication, it is also essential to realise that diagnosis is also about the reasons why a person has developed problems. Focusing on a single word entity distracts diagnosis from obtaining this personal understanding.
Idealised diagnostic descriptions are not entities as such. This truth has been lost in the pursuit of DSM-5, which should be abandoned. There are alternative ideas about comprehensive diagnosis which could be developed (eg. see World Psychiatric Association (WPA) conference report). Allen Francis has recently suggested in NYTimes that a new organisation is needed to take over from the American Psychiatric Association, but I'm not quite sure why he doesn't consider WPA.