The World Health Organization (WHO) puts the number of individuals with dementia at 35.6 million worldwide. Unless researchers successfully find a way to slow down the decline in brain function or prevent the onset of the disease, this number will double every two decades.

In a bid to put an end to the disease, which affects about 800,000 individuals in the United Kingdom, UK Prime minister David Cameron is set to announce a drive to develop medicines that would slow down the onset of Alzheimer's disease, the most common form of dementia, or find a cure for the chronic disease by 2025.

On Thursday, the prime minister will attend a summit of health and finance leaders in London to speak about the implications of dementia and the urgent need to find a treatment for the illness which causes personality disorder, memory problems and impaired reasoning.

Cameron wants to double the spending on dementia drug research, which to date, only amounts to one fifth of that allocated for cancer research. He will also urge businesses and governments to accelerate the development of new drugs as the number of individuals with dementia is anticipated to double every twenty years. Despite the continued prevalence of dementia, only three dementia drugs were developed in the last 15 years.

Economic implications are also at stake with the development of new drugs. A dementia drug that could delay the onset of the disease by three years could result in an annual savings of £5 billion in Britain.

"The truth is that dementia now stands alongside cancer as one of the greatest enemies of humanity," says the Prime Minister, who will be discussing the matter at the upcoming conference. "We have to fight to cure it. I know some people will say that it's not possible, but we have seen with cancer what medicine can achieve."

The Medical Research Council will also unveil the world's largest study of dementia during the event. The study will involve 2 million participants from the U.K who will share their medical and lifestyle information to help researchers identify the risk factors for the disease.

While previous studies on dementia involved patients who have already developed the disease, the new study, a collaboration of the Medical Research Council, eight universities and six pharmaceutical and biotech companies, will involve adults who do not have the disease. The objective of the study is to track people without dementia to find patterns in those who may develop the illness in the future.