[en] Computed tomography (CT) was employed to follow up 28 patients with senile mental disorders (52 to 84 years of age) over a period of one to six and a half years after the first presentation. The first CT scans showed ventricular enlargement in many instances, which made it difficult to distinguish functional from degenerative diseases. The yearly rate of ventricular enlargement was, therefore, obtained on sequential CT scannings. The yearly rate of ventricular enlargement was high, which was associated with progression of the disease in the group with Alzheimer's disease. In the group with functional diseases, however, ventricular enlargement and progression were independent of each other. Both the yearly rate of ventricular enlargement and mental function significantly correlated with decreased adaptation of daily life. Periodical CT scanning and clinical observation over a certain period may offer useful information on the differential diagnosis and prognosis of senile mental disorders. (Namekawa, K.)