Multivariate analyses of CT findings in typical schizophrenia and atypical psychosis.

In order to investigate the brain morphological differences between typical schizophrenia and atypical psychosis, the brain CTs of 41 patients with typical schizophrenia, 27 patients with atypical psychosis (ATP), and 20 controls were examined. The schizophrenics had larger values for 9 CT indices, i.e., interhemispheric fissure (IHF) index, VBR, 2 lateral ventricles (L-V) and 3rd ventricle (III-V) indices, and 4 sylvian fissure (SF) indices, while the values of ATP patients for 3 SF indices were greater than for the controls. Moreover, the schizophrenics had greater III-V and L-V indices than the ATP patients. The correlation matrix of CT indices indicates that the III-V index correlated well with the other CT indices, whereas the VBR, IHF and right SF indices did not. Therefore, it was speculated that there might be 3 subgroups, each of which has a main focus of alteration in the above-mentioned regions. Therefore, all the cases were divided by means of a cluster analysis into 5 groups. Group I, which contained mainly normal controls, and Group II, which consisted mainly of atypical psychosis patients, had no abnormal CT findings. Group III, which comprised mainly ATP patients and paranoid type schizophrenics, had right SF enlargement. Group IV, which showed significant IHF enlargement, and the residue group, which had larger VBR and significant left SF enlargement, consisted mostly of schizophrenics. Thus, our results suggest that the classification by CT data corresponds on the whole to our clinical diagnosis, according to which schizophrenic psychosis is divided into typical schizophrenia and atypical psychosis, and that each of the two psychosis groups may be further classified into distinct subgroups.