Factors related to changes in symptoms after the great Hanshin Earthquake in patients with dementia were studied. Interviews were conducted with family members of thirty patients given the diagnosis of dementia at the Center for Elderly Dementia of Hyogo College of Medicine between August 1993 and December 1994. The earthquake occurred on January 17, 1995, and the interviews were conducted three months later. Patients were classified into two groups: Group 1: those whose symptoms changed after the earthquake (n = 13); Group 2: those whose symptoms did not change after the earthquake (n = 17). Symptoms were exacerbated within 1 week after the earthquake. The percentage of patients with mild dementia was higher in Group 1 than in Group 2. Scores on the Mini-Mental State examination and on Hasegawa's dementia scale were lower in Group 2 than in Group 1. On a modified GBS-scale, patients in Group 2 scored higher than those in Group 1 in impaired intellectual function and in reduced motivation, and they scored lower than those in Group 1 in impaired emotional function. CT scans showed that cortical atrophy and ventricular enlargement were greater in Group 2 than in Group 1. These findings suggest that after the earthquake symptoms became more severe in patients with mild dementia at an early stage, who have anxiety, irritability, and emotional lability.