Symptom segregation in chronic schizophrenia: the significance of thought disorder

Forty-two schizophrenics in chronic stages were evaluated using the standard and modified SANS for negative symptoms, and the SADS for positive symptoms. The results of principal components analysis of the two scales were then compared. Analysis of the modified scale scores showed that thought disorder belonged to a unique syndrome orthogonal to both the positive and negative syndromes, which was designated disorganization syndrome. Cluster analysis of the modified scores revealed two major clusters, one of which consisted of the subjects with high disorganization syndrome scores. This subgroup was not identified using the standard SANS scores for analysis. The disorganization syndrome included thought disorder, bizarre behavior, and attentional impairment. Similarities between Hecker's hebephrenia and the disorganization syndrome detected in the present study were noted.