Heterogeneity among schizophrenic patients: selective review of recent findings (1970-75)

Abstract

This selective review of the past 5 years' literature on the utility of dividing schizophrenic patient samples into more homogeneous subgroups indicates that this research direction continues to hold definite promise for increasing scientific knowledge of the etiology, process, and treatment of schizophrenia. In fact, this body of findings suggests that little remains to be gained from studies in which heterogeneous samples of schizophrenic patients are contrasted with matched samples of nonschizophrenic control subjects. The psychiatric and psychosocial dimensions of chronicity, paranoid status, and premorbid adjustment were the initial dimensions used in the formation of more homogeneous subgroups of schizophrenic research subjects. The recent studies cited in this paper attest to their continued success as the basis for empirically useful and theoretically valid research methods and designs. It does seem, however, that their contribution to the scientific study of schizophrenia has reached a plateau. Or, stated in a more precise way, the dimensions of chronicity, paranoid status, and premorbid adjustment have been found to account for only a portion of the variance on measures of schizophrenic pathology, treatment response, and prognosis. More statistically powerful, perhaps more central, independent variables may be available. Biologically based dimensions of genetic loading, autonomic arousal, and degree of CNS involvement appear to hold much promise for new methods of accounting for heterogeneity among schizophrenic patients. Although these biological dimensions are of more recent usage in schizophrenia research, the currently available findings suggest that they are equal to or greater (in predictive and treatment utility) than psychiatric and psychosocial dimensions.