This study investigated the differences in the response characteristics found in the drawings by dementia
patients and by schizophrenia patients on the Clock Drawing Test (CDT henceforth). The participants in this
study were 189 elderlies (97 schizophrenia patients and 92 dementia patients). The study instrument was
the CDT. The drawings were scored based on a 9 scale scoring system by 河野和彦 (Kono Kazhico, 2005).
A t-test was conducted to analyze the differences in the CDT drawings between the dementia group and
schizophrenia group. Frequencies and percentage were calculated to analyze the response characteristics
found in the drawings. The findings of this study are as follows. First, significant differences between the
dementia and schizophrenia group were found in the total score and the subcategories such as the number
and clock hands. Second, in the circle domain, average-sized circles were found more in the dementia
group's drawings than in the schizophrenia group's drawings. In many cases, the circles were in a distorted
shape. In the number domain, lack of numbers and overlapped numbers were found more in the dementia
group's drawings than in the schizophrenia group's drawings. In many cases, the numbers were in a tilted
position. In the clock hand domain the dementia group's drawings showed such cases as no clock hands,
incorrect position of clock hands, and the clock hands not passing through the center more than the
schizophrenia group's drawings. These findings suggest that the dementia group performed lower on the
clock drawing test than the schizophrenia group. The significance of this study is that this study provided
a validity of using the CDT as a projective tool by showing the differences in the response characteristics
in the CDT drawings by the dementia group and by the schizophrenia group.