The Effects of Donepezil on 15-Item Geriatric Depression Scale Structure in Patients with Alzheimer Disease

BACKGROUND/AIMS In Alzheimer disease (AD), depression is among the most common accompanying neuropsychiatric symptoms and has different clinical manifestations when compared with early-life depression. In patients with drug-naïve AD, we tried to explore the structure of the 15-item Geriatric Depression Scale (GDS15) and the effect of donepezil on these substructures. METHODS GDS15, cognitive function, and activities of daily living function tests were administered to 412 patients with probable AD who had not been medicated before visiting the hospital. Using principal component analysis, three factors were identified. The patients with AD who received only donepezil were retrospectively analyzed and we compared the change of cognition and GDS15 subgroup after donepezil medication. RESULTS Our study identified three factors and revealed that the GDS15 may be comprised of a heterogeneous scale. The Barthel index was significantly correlated with factor 1 (positively) and factor 2 (negatively). The Korean version of the MMSE (K-MMSE) was significantly correlated with factor 2 and factor 3. Compared to the baseline state, K-MMSE and GDS15 showed significant improvement after taking donepezil. Among GDS15 subgroups, factor 2 and factor 3 showed significant improvement after donepezil treatment. CONCLUSIONS These results suggest that the GDS15 may be comprised of a heterogeneous scale and donepezil differentially affects the GDS15 subgroup in AD.