This study compares the diagnostic terminology used for 592 consecutive discharges from a psychiatric unit before and after teaching psychiatric trainees the use of the ICD-9 classificatory system. The results show a marked increase in specificity of diagnostic labels, with a decrease of diagnoses with the term ‘not otherwise specified’, and an increase in the diagnoses of organic psychoses, paranoid and hebephrenic schizophrenia and depressive neurosis. The implications of this for training about diagnosis, clinical practice and recording of data for national statistics are discussed.

At the turn of the century Kraepelin brought together the disparate syndromes of hebephrenia, dementia paranoides, and catatonia under the rubric of dementia praecox. At the same time he crystallized the concept of manic-depressive illness as an entity discrete and separate from the former syndrome. In the years since Kraepelin's classification first came to be adopted, the definitions and descriptions of these two major disorders have undergone many changes. In an attempt to comprehend the meaning and the mechanism of the psychoses, Bleuler was drawn by the emergent theories of psychoanalysis to extend Kraepelin's clinical observations into the realm of psychology. He renamed dementia praecox the schizophrenias, thus emphasizing his idea that the splitting of associative processes was a fundamental feature of the syndrome; and he added the subcategory of simple schizophrenia. American psychiatry, dominated until recently by psychoanalytic concepts, has been influenced more by Bleulerian than Kraepelinian contributions. However, it has not restricted itself to Bleulerian notions. As Kety (1980) remarked in his Maudsley Lecture, great liberties have been taken with the syndrome of schizophrenia; the essential features have been altered, primarily by an expansion of its boundaries.

The shortcomings of the DSM-II classification of organic brain syndrome are described, including the limitation of the concept to the global brain disorders; the idiosyncratic use of the terms acute and chronic; and the unsatisfactory categories psychotic and nonpsychotic. Organic brain syndrome is defined according to DSM-III and the 10 separate brain syndrome categories are outlined. The diagnostic criteria for each category are listed and the general principles underlying the criteria are described. Finally, the goals of the authors' of DSM-III to enhance diagnostic reliability and validity are discussed and the impact of the new nomenclature is assessed.