Many people confuse dementia and Alzheimer’s disease thinking they are one and the same. This is because the terms are often used interchangeably, even by health professionals.
However, these conditions are not the same thing.
Dementia is described as the global deterioration of intellectual functioning resulting from atrophy of the central nervous system.
Dementia is characterized by loss of cognitive ability and is severe enough to interfere significantly with usual activities of daily living, work or social relationships. Memory, judgement and abstract thought are also impaired, though the individual’s level of consciousness is not affected. (1)
Dementia is not a normal part of aging, although the greatest known risk factor is increasing age, with the majority of people affected being over the age of 65.
In 2012 The World Health Organization described dementia as a public health priority, saying an estimate of 35.6 million people were living with the condition.(2) However, only three years later in 2015, the World Alzheimer’s report stated that 46 million people were living with dementia.(3)
Dementia can be caused by more than 50 different disorders with the most common causes including:
- Neurological diseases including Alzheimer’s disease.
- Disorders that affect the blood circulation in the brain such as strokes.
- Infections of the central nervous system such as meningitis.
- Long-term alcohol or drug use.
- Certain types of hydrocephalus, characterized by a build-up of fluid in the brain.
- There are also some reversible types of dementia.
Alzheimer’s disease is a subset of dementia and is the most common type, being responsible for up to 70 percent of all dementias.(4) It is an age-related, non-reversible, progressive disorder, which damages the brain, resulting in impaired memory, thinking and behavior.
The exact cause is unknown and there is currently no cure.
Consequently, one of the most common early symptoms of Alzheimer's disease is difficulty with short-term memory and learning new information.
As the disease develops, it leads to increasingly severe symptoms, including disorientation to time and place, mood and behavior changes, deepening confusion as well as unfounded suspicions.
As the disease progresses, memory loss and behavior changes become more severe, culminating in difficulty speaking, swallowing and walking in the later stages of the illness.
Although dementia and Alzheimer's disease hold a lot of similarities, they are not the same. Dementia is an umbrella term used to describe a collection of signs and symptoms characterized by cognitive decline. However it is not a disease in itself, while Alzheimer’s disease is.
Being one of the many forms of dementia, Alzheimer’s disease is a specific brain disease and one of the main causes of dementia. People can therefore have forms of dementia that are unrelated to Alzheimer’s disease.
Reviewed April 27, 2016
By Michele Blacksberg
Edited by Jody Smith
Stuart-Hamilton. I (2015) The Psychology of Ageing: An Introduction. 5th Ed. London. Jessica Kingsley Publishers.
Dementia. A Public Health Priority 2012. World Health Organization April 25 2016.
Dementia. World Alzheimer’s Report 2015 – The Global Impact of Dementia. Alzheimer’s Disease International. April 25 2016.
Alzheimer’s Disease. National Institute of Neurological Disorders and Stroke. April 25 2016.