Vortioxetine Treatment for Depression in Patients with Prodromal vs Mild Alzheimer's Disease: A Six-Month, Open-Label, Observational Study

Background: Depressive symptoms are common in Alzheimer disease (AD) from the prodromal stage. The benefits of antidepressants have been investigated in patients with AD dementia with mixed results. Objectives: This study aimed to compare the efficacy of vortioxetine in prodromal and mild-to-moderate AD patients with depression, and to assess the comparative effect on secondary measures, including behavioral disturbances, cognitive function, and activities of daily living. Participants: All subjects with AD at a single-center dementia center underwent a standard evaluation with mini-mental state examination (MMSE), basic and instrumental activities of daily living (BADL and IADL), geriatric depression scale (GDS), neuropsychiatric inventory (NPI), and clinical evaluation every six months. Measurements: The study specifically assessed patients on vortioxetine with available six-month follow-up data. The changes in GDS, NPI, MMSE, BADL/IADL at six months in the entire AD population and mild-to-moderate AD vs prodromal population were analyzed using repeated measure multivariate analyses. Linear regression analyses were implemented to evaluate baseline demographics and clinical characteristics associated with depressive and cognitive improvements at six months. Results: Out of 680 AD patients, 115 were treated with vortioxetine, and 89 with six-month follow-up data were included in the analyses. A significant improvement at follow-up was observed for GDS, NPI total and sub score items (mood, anxiety, apathy, sleep disturbances, eating abnormalities). Both mild-to-moderate and prodromal AD showed a positive GDS response, whereas mild-to-moderate AD showed a better improvement on total NPI and apathy/nighttime behaviors subitems compared to prodromal AD. Higher baseline GDS score was the only variable associated with higher responses in linear regression analyses. MMSE showed a significant improvement at six months in the entire cohort, with a greater effect in prodromal vs mild-to-moderate AD. Cognitive improvement (i.e., MMSE changes) was associated with cognitive status at baseline but independent of the antidepressant/behavioral changes (i.e., GDS/NPI). Conclusions: Our results suggest that vortioxetine is highly tolerable and clinically effective in both prodromal and mild-to-moderate AD with depression. Patients with mild-to-moderate AD benefited more from a wide range of behavioral disturbances. The study also showed significant improvement in global cognitive measures, especially in prodromal AD subjects. Further studies are needed to investigate the independent beneficial effect of vortioxetine on depression and cognition in AD.