Depression in old age—the first step to dementia?

A better understanding of the link between depression and dementia is essential, given the rapid growth of the elderly population, with an anticipated doubling of global dementia prevalence every 20 years. 1 Prince MJ Wimo A Guerchet MM Ali GC Wu Y-T Prina M World Alzheimer's report 2015–the global impact of dementia. Alzheimer's disease international. http://www.alz.co.uk/research/world-report-2015Date: 2015 Google Scholar In the Lancet Psychiatry, the findings presented from the study by Saira Mirza and colleagues 2 Mirza SS Wolters FJ Swanson SA et al. 10-year trajectories of depressive symptoms and risk of dementia: a population-based study. Lancet Psychiatry. 2016; (published online April 29.)http://dx.doi.org/10.1016/S2215-0366(16)00097-3 Google Scholar have brought us one step closer to answering whether depression is a risk factor for dementia or vice versa. They assessed different trajectories of depressive symptoms and their association with subsequent dementia in a large community sample of older adults over the course of 10 years. The beauty of their study is the identification of five different depression trajectories: stable low, decreasing, remitting, increasing, or stable high depressive symptoms over ten years. With results analysed by a Cox proportional hazards model adjusted for age, sex, APOEɛ4 carrier status, educational level, body-mass index, smoking, alcohol consumption, cognitive score, use of antidepressants, and prevalent disease status at baseline, only the trajectory with steadily increasing depressive symptoms was linked to a higher risk of dementia, compared with the low trajectory (hazard ratio 1·42, 95% CI 1·05–1·94; p=0·024). 10-year trajectories of depressive symptoms and risk of dementia: a population-based studyRisk of dementia differed with different courses of depression, which could not be captured by a single assessment of depressive symptoms. The higher risk of dementia only in the increasing trajectory suggests depression might be a prodrome of dementia. Full-Text PDF