Dementia causes the (usually gradual) loss of mental abilities such as thinking, remembering and reasoning. It is not a disease, but a group of symptoms that may accompany some diseases or conditions affecting the brain. The most common symptoms include loss of memory, confusion, and changes in personality, mood and behaviour.

Dementia usually affects older people and becomes more common with age. About one in 20 people over the age of 65 will develop some degree of dementia. This figure increases to about one in six people over the age of 85. Dementia can develop in younger people, but is less common, affecting about one in 1,400 of those under 65.

Although most of the people who develop dementia are over the age of 60, it's important to remember that dementia is not a normal part of growing old.

If you have dementia, it may have implications for driving. See the 'useful links' section for how to inform the DVLA about medical conditons.