Factor structure of symptoms in functional psychoses.

Global ratings from the Scale for the Assessment of Positive Symptoms and Scale for the Assessment of Negative Symptoms were subjected to principal-component analysis (PCA) in 80 schizophrenia patients, 76 patients with schizophreniform disorder, 80 patients with schizoaffective and mood disorders, and 78 patients with delusional, brief reactive, and atypical psychoses. The resulting factors were correlated with depressive, manic, and catatonic syndromes, and subjected to a multivariate analysis of variance across DSM-III-R diagnoses. PCAs revealed that psychosis, disorganization, and negative factors were also present in each of the nonschizophrenic groups. The disorganization factor tended to be related to the manic syndrome, and the negative factor to depressive and catatonic syndromes. Overall, the three factors had little diagnostic relevance in functional psychoses, although the negative factor was relatively more characteristic of schizophrenia. The data suggest that positive, negative, and disorganization factors are not specific to schizophrenia; this is consistent with a dimensional view of psychopathology in functional psychoses.