Depression in dementia: epidemiology, mechanisms, and treatment

Purpose of review Depression in people with dementia has important implications, such as reduced quality of life of patients and carers, and is associated with increased costs and reduced cognition. Here, we review recent studies of the epidemiology, course, mechanisms and treatment of depression in people with dementia. Recent findings Depression is both a risk factor and a prodrome of Alzheimer's disease. Depression is a common occurrence in all types of dementias and at all disease stages, including in mild cognitive impairment (MCI). Many studies have explored whether depression in MCI increased the conversion rate to dementia, but findings are inconsistent. Studies of the mechanisms are relatively few and findings inconsistent, but inflammatory, trophic and cerebrovascular factors may contribute, in addition to monoamine deficiency and severity of plaques and tangle pathology. Studies of antidepressants for depression in dementia are inconclusive, with several negative findings reported in recent large studies, suggesting that antidepressant may not confer benefit over placebo. Summary Depression is a common risk factor, prodrome, and accompanying symptom of people with Alzheimer's dementia. The mechanisms are unknown, and there is little evidence of effective therapies.