Negative symptoms and cognitive deficits: what is the nature of their relationship? Schizophr Bull

Negative symptoms and cognitive deficits in schizophrenia share many features and are correlated in their severity on a cross-sectional basis. The question arises as to the nature of this relationship: are these symptoms the same, caused by the same factor (or factors); or is the nature of their re-lationship determined by other factors, such as definitional issues and common correlates? In this article we provide a conceptual overview for addressing this question and provide a selective review of the literature on the cross-sectional and longitudinal relationships between these two features of the illness. We describe 4 different models of the ‘‘true’ ’ relationship between these variables. Some data suggest that the relationship between these variables is determined by the definition of negative symptoms employed and that, in general, the correlation is moderat