An empirical analysis of latent structures underlying schizophrenic symptoms: a four-syndrome model

Various models of schizophrenia have postulated two syndromes (i.e., positive and negative), although other exploratory factor analyses have suggested a disorganization syndrome. We conducted a confirmatory factor analysis (CFA) on Schedule for the Assessment of Positive Symptoms (SAPS) and Schedule for the Assessment of Negative Symptoms (SANS) items and subscales to assess the latent structure of symptoms reflecting underlying pathological processes. The sample included 253 DSM-IIIR schizophrenic inpatients. Fourteen different models with one, two, three, or four syndromes were compared using CFA for "goodness of fit." The three-syndrome models displayed better fitness than any of the one- or two-syndrome models. All of the three-syndrome models shared the positive and negative dimensions; the third dimension in these three-syndrome models was either the disorganization or Strauss' relational dimensions. In the reported data, a four-syndrome model, including positive, disorganization, negative, and relational dimensions, showed excellent fitness. Despite its limitations, this study suggests the need to explore the validity of a four-syndrome model. The positive-negative model fits poorly with the data.