Revisiting the factor structure for positive and negative symptoms: evidence from a large heterogeneous group of psychiatric patients
Journal Title
American Journal of Psychiatry
Keywords
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Publication Date
1997-03
Book Title
Publication Volume
154
Publication Issue
3
Publication Begin
371
Publication End
377
Number of pages
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Abstract
O bjective: The factor structures of individual positive and negative symptoms as well as global
ratings were examined in a diagnostically heterogeneous group of subjects. Method: Subjects
were identified through a clinical and family study of patients with major psychoses at a VA
medical center and evaluated with the Scale for the Assessment of N egative Symptoms and the
Scale for the Assessment of Positive Symptoms. For the examination of global-level factor
structures (N =630), both principal-component analysis and factor analysis with orthogonal
rotation were used. Factor analysis was used for the examination of item-level factor structures
as well (N =549). Results: The principal-component analysis of global ratings revealed three
factors: negative symptoms, positive symptoms, and disorganization. The factor analysis of
global ratings revealed a negative symptom factor and a positive symptom factor. The itemlevel factor analysis revealed two negative symptom factors (diminished expression and disordered relating), two positive symptom factors (bizarre delusions and auditory hallucinations), and a disorganization factor. Conclusions: The generation of additional meaningful
factors at the item level suggests that important information about symptoms is lost when only
global ratings are viewed. Future work should explore clinical and pathological correlates of
the more differentiated item-level symptom dimensions