Depressive Symptoms are Associated with Progression to Dementia in Patients with Amyloid-Positive Mild Cognitive Impairment.

BACKGROUND: Depressive symptoms are prevalent in patients with mild cognitive impairment (MCI) and are considered to be a risk factor for progression to dementia. OBJECTIVE: The purpose of this study was to evaluate whether depressive symptoms in MCI promote disease progression in a manner related to amyloid status, and to determine the relationship between depressive symptoms and longitudinal cerebral structural changes. METHODS: Baseline data for 336 patients with MCI (75 with depression and 261 without) from the Alzheimer's Disease Neuroimaging Initiative study were analyzed. All participants underwent comprehensive cognitive testing, volumetric magnetic resonance imaging (MRI), and [18F]AV45 positron emission tomography amyloid imaging. Depressive symptoms were measured using the Neuropsychiatric Inventory Questionnaire. A voxel-based morphometric analysis using volumetric brain MRI data was used to compare longitudinal structural changes related to depressive symptoms. RESULTS: The conversion rate to dementia was different between patients with and without depression in amyloid-positive MCI (40.8% versus 19.7%, respectively; p = 0.006). Patients who were amyloid-positive at baseline also exhibited a greater degree of 2-year cognitive decline. Depression in amyloid-positive MCI was associated with longitudinal cortical atrophy in the left cingulate gyrus. CONCLUSION: Our study indicates that the presence of depressive symptoms in patients with amyloid-positive MCI is associated with higher progression to dementia and longitudinal cortical atrophy.