'Conspiracy of silence' over dementia in the doctor's surgery She said: "These responses provide an intriguing insight into the reality of the UK's poor levels of diagnosis for Alzheimer's Disease. The findings suggest an unwillingness to engage on both sides of the consulting room table, leading to a conspiracy of silence around this devastating disease. While companies like Lilly search for new medicines to help treat Alzheimer's, we must all work together to reduce the stigma that is holding early and accurate diagnosis back. Almost three-quarters of the doctors surveyed cited the lack of a definitive dementia test as a reason for their reluctance to raise the matter with patients. Telling early dementia from normal ageing can be difficult. In the past GPs have sometimes refrainedgiving patients the bad news - even those with clear signs - because little could be done for them. However, now drugs are available on the NHS that can slow the advance of Alzheimer's, the most common form of dementia. The earlier they are given, the better. Dementia is thought to affect around 800,000 people in Britain, but only four in 10 have received a formal diagnosis, according to The Alzheimer's Society. The survey results were released ahead of World Alzheimer's Day, which is tomorrow (Friday).