As people are living longer, dementia is becoming a signi?cant issue for society. Dementia is now recognised as a major concern in society, and the numbers of people estimated to have dementia in the UK population appear to have stabilised at around 700,000 (1,2). Globally, 35.6 million people are estimated to meet criteria for dementia, a number predicted to double every 20 years (3). Given the absence of treatments that signi?cantly alter the natural history of the clinical syndrome of dementia, there has been increased emphasis on early diagnosis, with research exploring assessment tools and biomarkers that might predict with certainty a particular clinical outcome. At the same time, there has been pressure to focus on biomedical pro?les, which assume a very close link between the pathobiology and the manifest clinical syndrome.