Dementia is the progressive loss of the powers of the brain. The most common cause is Alzheimer's disease. Other kinds of dementia are vascular dementias (including multi infarct dementia), alcohol-related dementias, Lewy body dementia and Pick's disease. What all these diseases have in common is that they damage and kill brain cells, so that the brain cannot work as well as it should.

In Scotland, approximately 62,000 people have dementia. It is most common in older people but can affect people in their 40s or 50s or even younger.

Check out our guide to dementia