The negative syndrome as a dimension: factor analyses of PANSS in major depressive disorder and organic brain disease compared with negative syndrome structures found in the schizophrenia literature.

OBJECTIVE: To explore the concept of the negative syndrome as a dimensional entity that exists in multiple primary diagnoses, and to compare the negative syndrome in nonschizophrenic disorders and schizophrenia.
BACKGROUND: Although initially considered specific to schizophrenia, the negative syndrome has subsequently been described in major depression, stroke, and dementia.
METHOD: We performed an exploratory factor analysis on Positive and Negative Symptom Scale scores of 82 subjects with major depressive disorder and 76 subjects with organic brain disease (dementia or stroke).
RESULTS: The examination of the resultant symptom clusters revealed that the structure of the negative syndrome in major depressive disorder and organic brain disease closely corresponded to that in schizophrenia literature.
CONCLUSIONS: The negative syndrome may be a nosologic entity, which remains fairly consistent across psychotic and nonpsychotic diagnostic categories. Confirmatory studies are merited to determine the degree and strength of the similarity in structure of the negative syndrome in psychotic, affective, and cognitive illness.