THE SOURCES OF CONVERGENCE BETWEEN MEASURES OF APATHY AND DEPRESSION

Apathy and depression are discriminable but related dimensions of beha vior. The purpose of this study was to evaluate the source of the over lap between measures of apathy and depression. We evaluated the interc orrelations between the Apathy Evaluation Scale (AES) and the Hamilton Rating Scale for Depression (HamD) in 107 subjects, aged 53-85, who m et research criteria for normal aging, left or right cerebral hemisphe re stroke, probable Alzheimer's disease, or major depression' We deter mined the correlation between the individual items on the HamD and the total scores on the AES and the HamD. The HamD items having the stron gest correlations with AES total score were diminished work/interest, psychomotor retardation, anergy, and lack of insight. The correlation between AES and HamD total scores was nonsignificant when major depres sion subjects and these variables most closely related to apathy were excluded from consideration. These findings indicate that the converge nce between HamD and AES is attributable to (i) a subset of HamD items which are consistent with the syndrome of apathy and (ii) the fact th at major depression is associated with both apathy and depression. Cli nical and research applications of these results are discussed.