“Dementia Praecox” was discarded when it became apparent that a true dementing process was not present in schizophrenia. Most writers agree with the view put forward by French authors that the deterioration in schizophrenia is not the same as that seen in the organic psychoses (Lehrmann, 1940). Experimental work has indicated that intellectual deterioration in schizophrenia is more apparent than real, and that as it appears most when sustained effort and co-operation are required, any changes in co-operativeness and ability to maintain sustained effort invariably affect intelligence test scores (Kendig and Richmond, 1940; Sheldon Rappaport, 1951). The concept of schizophrenic deterioration employed in this article refers to a deterioration of behaviour in general, and to a deterioration of a patient's ability to look after himself in particular. With increasing interest in methods of treating deteriorated schizophrenic patients, we need reliable measures of deterioration in order to compare the effects of treatment in different groups. At present discrepancies in results are frequently due to some groups of schizophrenics being more deteriorated than others. For example Layman (1940) demonstrated that sodium amytal speeded up the psychomotor performances of schizophrenic patients, but subsequent work by Ogilvie (1953) did not confirm this finding. This discrepancy may have been due to the fact that Layman's schizophrenic group contained patients who were more deteriorated than the patients in Ogilvie's study. If a scale indicating the degree of schizophrenic deterioration could be devised, future researches into the treatment of deterioration in schizophrenia would benefit. There are a number of rating scales already available of which the best is probably the Fergus-Falls (Lucero et al., 1951). All of these scales have several common defects. They contain a number of items which are very subjective in nature and dependent more on the rater than the patient. Many are also of such length that they are too time-consuming to complete, particularly in the case of patients on long-stay wards where the nursing staff are invariably overworked already.