The role of persistent and incident major depression on rate of cognitive deterioration in newly diagnosed Alzheimer's disease patients

Depression may potentially impair the clinical course of Alzheimer's Disease (AD). Thus, the aim of this study was to investigate cognitive progression of AD patients with or without major depressive episode (MDE). In this one year longitudinal follow-up study conducted in three Italian memory clinics, 119 newly-diagnosed probable AD patients of mild severity, who were not undergoing treatment with acetyl-cholinesterase inhibitor (AChEI), and had not been treated with psychotropic drugs in the last 2years, were included. Patients were assessed to investigate the effect of baseline and one-year follow-up MDE (using modified DSM-IV diagnostic criteria for MDE in AD) on progression of global cognitive deterioration (using Mini-Mental State Examination (MMSE)), adjusted for confounding factors. Never being depressed was associated with a 3.1 (95%CI 1.0-10.1) increased risk of MMSE decline compared to recovered depression. Six times more patients with persistent depression had MMSE decline compared to patients with recovered depression. However, the largest odds (7.3; 95%CI 1.4-38.1) of cognitive decline was observed in patients who developed incident depression over follow-up. In conclusion, persistent or incident depression worsens cognitive outcome while no or recovered depression does not affect it in early AD patients.