Abstract

Dementia is a clinical diagnosis requiring new functional dependence on the basis of progressive cognitive decline and representing, as its Latin origins suggest, a departure from previous mental functioning. The incidence of dementia rises with age making it an increasingly common phenomenon within our aging population. The nature of symptoms mean people with dementia are more dependent and vulnerable, both socially and in terms of physical and mental health, presenting evolving challenges to society and to our healthcare systems. Despite the seemingly simple premise, the clinical diagnosis of dementia can be difficult with de novo functional impairment often obscured by physical frailty, comorbid psychiatric symptoms such as depression and a subtle but steady assuming of household responsibilities by spouses and family. Clinical and pathological criteria for the main dementia-causing diseases overlap significantly. The emergence of symptoms decades into the pathophysiological process hampers targeted disease therapy. The association of both overt cognitive decline and underlying pathophysiological processes with normal aging complicate the process of identifying disease processes early within the spectrum of normal aging. Once the diagnosis is established, prognostic measures are required, and are still lacking, as disease trajectories between individuals can vary greatly. Globally, governments are recognizing these challenges. Investment and research infrastructure are beginning to reflect the scale of the need. Drugs conferring symptomatic benefit are available and memory service structures exist to diagnose dementias and guide management. The personal impact of dementia on patients and families is also being increasingly recognized, with discussion in the media surrounding famous sufferers and dramatizations in literature and film.