To examine the differences on individual Hamilton depression scale items among the four study groups, we calculated a two-way ANOVA (four groups times 15 Hamilton depression scale items). There was a significant main effect (F=53.3, df=3, 127, p<0.0001) and a significant group-by-item interaction effect (F=5.4, df=42, 3038, p<0.0001). On individual comparisons, a significant main effect was found for all 15 Hamilton depression scale items (
Figure 1). (Hamilton depression scale items 1 and 17 were not included in the ANOVA but are shown in
Figure 1). The depressed patients with Alzheimer’s disease had significantly higher scores than the nondepressed patients with Alzheimer’s disease on the following Hamilton depression scale items: guilt (F=24.7, df=1, 152, p<0.0001), suicide (F=16.0, df=1, 152, p<0.0001), early insomnia (F=12.0, df=1, 152, p<0.001), middle insomnia (F=13.8, df=1, 152, p<0.001), late insomnia (F=11.2, df=1, 152, p<0.001), loss of interest (F=17.1, df=1, 152, p<0.0001), psychomotor retardation (F=23.6, df=1, 152, p<0.0001), agitation (F=11.6, df=1, 152, p<0.001), worry (F=37.4, df=1, 152, p<0.0001), anxiety (F=20.6, df=1, 152, p<0.0001), loss of energy (F=22.4, df=1, 152, p<0.0001), loss of libido (F=9.01, df=1, 152, p<0.01), hypochondriasis (F=24.0, df=1, 152, p<0.0001), and loss of weight (F=8.9, df=1, 152, p<0.01). No significant differences among groups were found for loss of appetite. (“Sadness” and “loss of insight” were not included in the ANOVA.) Healthy comparison subjects and nondepressed patients with Alzheimer’s disease showed no significant between-group differences for any Hamilton depression scale item. Finally, a comparison between the depressed patients with Alzheimer’s disease and the depressed patients without dementia demonstrated significantly higher scores for the latter on the following Hamilton depression scale items: suicide (F=33.4, df=1, 137, p<0.0001), anxiety (F=8.8, df=1, 137, p<0.01), loss of appetite (F=22.3, df=1, 137, p<0.0001), and loss of weight (F=19.1, df=1, 137, p<0.0001). However, the depressed patients with Alzheimer’s disease had significantly higher scores on psychomotor retardation (F=11.8, df=1, 137, p<0.001) than the depressed patients without dementia.
Diagnoses of major and minor depression were generated on the basis of SCID assessments. The frequencies of major depression were much higher for the depressed patients with Alzheimer’s disease than for the nondepressed patients with Alzheimer’s disease, whereas the frequencies for minor depression were somewhat higher for the same group. Only 4% (N=4) of the depressed patients with Alzheimer’s disease failed to meet criteria for either major or minor depression compared to 68% (N=42) of the nondepressed patients with Alzheimer’s disease. Among all patients with Alzheimer’s disease, a hypothesis of unequal frequency of minor, major, or no depression based on the presence of depressed mood (i.e., a score of 2 or higher on the “depressed mood” item on the Hamilton depression scale) was statistically substantiated (χ2=78.9, df=2, p<0.0001). A score of 2 or higher on the same item (as rated by the caregiver) had a sensitivity of 61% and a specificity of 94% for major depression, whereas the patients’ own ratings on this item had a sensitivity of 46% (42 of the 92 depressed patients with Alzheimer’s patients had a score of 2 or higher) and a specificity of 94% (four of the 62 nondepressed patients with Alzheimer’s disease had a score of 2 or higher).