The positive-negative dimension in schizophrenia: its validity and significance

It has been recently proposed that positive (productive) and negative (deficit) symptoms in schizophrenia constitute distinct syndromes that carry different etiological, prognostic, and treatment implications. Inconclusive results to date may be attributable to methodological weaknesses, including problems of measurement and lack of longitudinal, dynamic, and multiphasic investigation. We describe a series of multidimensional studies on the validity and significance of this distinction, deriving from a new rating instrument and separate typological, dimensional, longitudinal, phasic, and psychopharmacological research perspectives. The data suggest that positive and negative features represent opposing polarities of psychopathology which can be reliably assessed. Various sources of syndromal validation were demonstrated, including construct and criterion-related validity and differential response to psychotropic medication. Positive and negative syndromes were equally prevalent in the acute and chronic phases of schizophrenia but stable only in the latter. The meaning of the syndromes also varied according to chronicity. In the chronic stage, a negative profile was uniquely associated with ominous genealogical, premorbid, and phenomenological signs, whereas in acute schizophrenia it carried favorable import and predicted successful outcome. The results contest a monolithic concept of the positive-negative distinction and fail to support the prevalent hypothesis of structural organic impairment underlying the negative syndrome. We instead postulate a dual-process model that distinguishes between neuroleptic responsive arousal-related (positive) and neuroleptic resistant development (negative) components in chronic schizophrenia.