British experts have concluded that the number of people with dementia and Alzheimer's will almost double every 20 years worldwide, to 65.7 million in 2030 and 115.4 million in 2050.
According to a study published by Alzheimer's Disease International (ADI), the fact people are living longer than ever before is a major factor driving the increasing incidence.
Around 700,000 people in the UK currently have a form of dementia, with over half of these suffering from Alzheimer's. And the research has predicted that about 35.6 million people worldwide will have dementia in 2010.
Earlier, it was estimated that in less than 20 years nearly a million people in the UK will be living with dementia, soaring to 1.7 million people by 2051.
The study was led by Professor Martin Prince from the Institute of Psychiatry at King's College London, who said it highlighted issues about the pressure on carers.
He explained: "In all parts of the world, carers, who are most commonly female and the spouses or children of the persons with dementia, often experience high levels of strain.
"Studies reviewed in the new report suggest that half to three-quarters of carers have significant psychological illness, while up to a third have clinical depression."