Latent structures underlying schizophrenic symptoms: a five-dimensional model.

Latent structures of schizophrenic phenomenology were examined over the course of the illness in 100 newly-admitted patients. We compared the results of a confirmatory factor analysis (CFA) on ten competing models that had between zero and five dimensions using data assessed by the Positive and Negative Syndrome Scale (PANSS) at both the acute and chronic phases of the disease. The present findings did not support the two-dimensional construct of positive and negative symptoms in either the acute or the chronic phase of the illness. In the acute phase, a three- (positive, negative, and relational dimensions), four- (positive, negative, disorganization, and relational dimensions), and five-dimensional model (positive, negative, disorganization, excitement, and relational dimensions) fit the data relatively well. In contrast, in the chronic stable phase, only the five-dimensional model adequately fits the data. The present findings suggest that further investigation of the validity of the five-dimensional model over the course of the illness is necessary.