Despite the fact that schizophrenia has been known under one or another name for centuries, the nature of the disorder even at the descriptive level remains in no small measure yet to be determined. It is true that there is a voluminous literature describing the multifarious deviations from psychologic normality and no small number of publications dealing with organic variations. But the question is still open as to which of the deviations are essentially characteristic of the psychosis.

In the picture as presented by the patient we have to deal with pathologic phenomena of several different categories. The abnormalities may comprise the effects of bad hygiene, the effects of habituation, the effects arising primarily out of the fundamental cause or causes of the disorder and the defects arising from secondary operations of the primary causal factors. The need remains for an adequate definition of the psychosis. This definition should, of course, delimit it from all other disorders; it should be broad enough to include all of the subvarieties; it should include none but characteristic attributes. The literature on schizophrenia as now available, while profuse in qualitative material, is defective in its content of accurate quantitative information.

But an even more significant defect is the lack of homogeneity of the data as they exist. These data have been obtained by many investigators using different techniques on a variety of patients living under dissimilar environmental conditions. They are of correspondingly limited utility for the purpose even of formulating a technically satisfactory definition. In large part they are entirely unusable for the type of studies of correlation that is needed for the analysis of the problem as a problem. There is need, then, for the collection of an extensive body of descriptive data on a fairly large number of patients studied under uniform conditions. While it is true, as has been emphasized elsewhere, that the mere enumeration of traits is a research method of strictly limited utility, it is likewise true that attempts to carry out research on a problem that has not been accurately set are likely to result in numerous ineptitudes.

However, even at the descriptive level, certain substantial accomplishments can be hoped for. At this level can be studied the question as to whether schizophrenia represents a disease entity or whether, like fever or headache, it might as well represent a variety of essentially different disorders. The detection of disease entities has not infrequently been accomplished at this level. For example, myxedema was so discovered. In principle, this sort of discovery amounts to the detection of consistent syndromes.