Dementia represents a group of symptoms that are so severe that may interfere with a person’s daily functioning and includes the loss of intellectual functions like thinking, remembering, and reasoning.
The most common representative of dementia is Alzheimer's disease. Dementia can be caused by a disease or an injury and is irreversible in that case. It can be reversible if caused by drug and alcohol abuse, hormone or vitamin imbalances, or depression.

A new study conducted predicts rise in the number of people affected with the disease in the next forty years. Risk factors include changing lifestyles, greater longevity and the population explosion in developing nations. Today, 24 million people suffer from dementia, which is connected to cardiovascular disease, and old age. Each year, around 4.6 million new cases are being reported. Many cases of dementia are not reported, resulting in these cases not receiving any treatment.

It is expected that by the year 2020, the number of people afflicted will rise to 42 million, and to 81 million by the year 2040. South Asia and China will account for largest increases. By the year 2040, China is expected to account for as many people suffering from dementia as the entire developed world.

The Alzheimer's disease is believed to be caused by the amyloid beta protein plaques building up within the brain. Although there is no cure, there is a way to prevent the disease. The mental functions can be preserved through adopting a healthy lifestyle, which involves both physical and mental activity.