Dementia is the loss (usually gradual) 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. There are many different types of dementia, each with their own causes. The most common dementia 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 6 in 100 of those over the age of 65 will develop some degree of dementia, increasing to about 20 in 100 of those over the age of 85. Dementia can develop in younger people but is less common, affecting about 1 in 1,000 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, and most older people never develop dementia.

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