Dynamic characteristics of depressive symptoms and risk of all-cause dementia and Alzheimer's disease: Two population-based cohorts and evidence synthesis of longitudinal studies.

In ADNI, compared to the consistent absence of depressive symptoms, mild and increasing depressive symptoms trajectory, but not stable mild symptoms was associated with an increased risk of AD (HR = 2.33, 95 % CI = 1.33 to 4.82, p = 0.022).

Meta-analyses of 16 longitudinal cohorts revealed six trajectories significantly predicated escalated risk of dementia, including stable mild symptoms (relative risk [RR] = 1.43 %), stable high symptoms (RR = 1.74), increasing symptoms (RR = 1.68), adult-onset depression (RR = 1.38), mid-to-late life depression (RR = 1.84), and life-long depression (RR = 1.33).