Data from a previous study of ours, based on computerised tomography of the brain in 70 chronic schizophrenics, indicated that a severe degree of lateral brain enlargement was present in a great proportion. No correlation was found between lateral ventricular enlargement and age of patients, length of illness, duration of hospitalization or ECT treatment. In order to elucidate whether other factors (e.g. type of disease) are likely to correlate with the enlargement we divided these patients into three subgroups: hebephrenics, paranoids and undifferentiated. Comparison of the mean values of ventricular brain ratio (VBR) of the above groups showed that paranoids presented a statistically greater enlargement than hebephrenics. There was no statistically significant difference between undifferentiated and hebephrenics. The difference between undifferentiated and paranoids approached statistical significance. This study provides evidence that there exists a difference between the types of schizophrenia in CT images, a finding that may suggest different degrees of underlying disease process.