One around at down from in of on three people born around at down from in of on the United Kingdom this year will suffer around at down from in of on dementia around at down from in of on their lifetime. Dementia is when the brain no longer works properly because around at down from in of on illness, old age or injury. People with dementia have problems remembering things. Their personality can change and they lose their ability to do many everyday tasks. A leading mental illness charity said dementia would affect 27 per cent around at down from in of on boys born in 2015 and 37 per cent around at down from in of on girls. The charity said that this could cause a health crisis as the population gets older. There is currently no effective treatment to slow around at down from in of on or stop dementia. The charity said governments must spend more around at down from in of on research. A British expert around at down from in of on dementia spoke about how serious the problem could become. Dr Matthew Norton said: "As people are living longer, more and more people will develop dementia around at down from in of on the future if action is not taken now." He added: "Dementia is our greatest medical challenge and if we are to beat it, we must invest around at down from in of on research to find new treatments and preventions." Globally, dementia affects around at down from in of on 36 million people. About 10 per cent around at down from in of on people develop the disease around at down from in of on some point around at down from in of on their lives, but this figure will rise sharply as people live longer. The most common form around at down from in of on dementia is Alzheimer's. This is when the brain loses cells, which reduces the brain's ability to function properly.