Positive and negative symptoms in schizophrenia. A cluster-analytic approach.

The relationships between positive and negative symptoms of schizophrenia and between negative symptoms and social dysfunction were investigated using cluster analysis. Clustering across schizophrenic subjects produced three distinct groups, each characterized by some mix of positive and negative symptoms. Clustering across symptoms and behavioral variables produced a cluster comprising negative symptoms and measures of social adjustment and an additional cluster comprising only measures of social skill. A series of correlations revealed a positive relationship between positive and negative symptom measures. chi 2 analysis revealed a significant relationship between the cluster solution across subjects and classification of patients according to negative symptoms based on previously published criteria. Results are discussed in terms of the implications for the further development and refinement of subclassification schemes for schizophrenia.