What is dementia?

The term "dementia" doesn't actually refer to one, specific disease. Rather, it's an overall term for a set of symptoms that are caused by disorders affecting the brain.

Senior man thinking pensively.

Looking for a quick summary of dementia you can print and share? Read our downloadable, one-page document: What is dementia? (PDF). Also available in other languages.

Dementia is not a normal part of aging

Almost 40% of people over the age of 65 experience some form of memory loss. When there is no underlying medical condition causing this memory loss, it is known as age-associated memory impairment.

Age-associated memory impairment is part of the natural process of aging. For most people, memory generally remains strong as they get older, and doesn't decline rapidly or substantively.

However, brain diseases like Alzheimer’s disease and other dementias are different.

Know the differences between normal aging and dementia.

Dementia doesn't just affect older people

The idea that dementia is an "old person's disease" is not just stigmatizing, it's also a myth.

While most people living with dementia are over the age of 65, a small number of people in their 40s and 50s can and do develop dementia. This is known as young onset dementia.

Get more answers to common myths about dementia.

Dementia causes more than memory loss

Symptoms of dementia include:

  • Memory loss, both short-term and long-term,
  • Difficulties with thinking, problem-solving or language that are severe enough to reduce a person's ability to perform everyday activities, and
  • Changes in mood or behaviour.

Understand the symptoms of dementia.

Dementia is progressive

As more brain cells become damaged and eventually die, the symptoms of dementia will gradually get worse. That's why it's important to be diagnosed as early as possible.

Learn more about the different stages of Alzheimer's disease, the most common type of dementia.

Dementia does not always imply Alzheimer's disease

While Alzheimer's disease is the most common form of dementia, there are other types, such as:

These conditions can have similar and overlapping symptoms.

Know the difference between Alzheimer's disease and dementia.

People living with dementia are still people

Because of the effects of dementia, a person’s ability to communicate may become impaired, making it difficult to talk with them. But this doesn't meant they should be ignored.

It's important to try to reach the person in whichever way you can – and there are many ways to do so. While the effects may not be immediately obvious, your efforts can improve their quality of life and help the person living with dementia feel more comfortable and secure.

Know that all persons with dementia have the right to be treated with respect.

Learn more about stigma against dementia.

Dementia is becoming more common in Canada – and more expensive

With over half a million Canadians living with Alzheimer's disease or another form of dementia, chances are you know someone living with dementia. As our population ages, this number will nearly double by 2030.

Last year, total healthcare system costs and the out of pocket costs of caring for people living with dementia were at least $10.4 billion. Unless we do something now, dementia will become an even more serious impact on our healthcare system.

Get the full list of dementia numbers in Canada.

What causes dementia is unknown...for now

While we know that neurodegenerative diseases, vascular diseases, head injuries and other risk factors can increase the chance of dementia, we still don't know what exactly causes dementia.

However, researchers around the world are working hard to unravel the mysteries of the disease, and find not just the cause of dementia, but better treatments and a cure as well.

Find out what the current research is telling us about dementia.

Didn't find what you were looking for? Get more answers to common questions about dementia. Or contact us with your questions at info@alzheimer.ca.

More useful links and resources

What is dementia? Alzheimer Society of Canada, 2020. This one-page document will introduce you to the basic facts around dementia, including the differences between dementia and normal aging, the importance of early diagnosis and what to do if you’re concerned that you or someone you know has dementia.

Also available in other languages

Indigenous views on dementia

Dementia. Native Women’s Association of Canada, 2020. In addition to providing basic information on dementia, this one-page, downloadable factsheet includes a brief summary of Indigenous views on dementia.

Dementia numbers in Canada

The Alzheimer Society is committed to providing accurate and reliable data on dementia in Canada. Statistics listed on this page are the most current available and are updated periodically when new reports and studies are issued.

Learn more
Caregiver and senior man living with dementia walking home together from the grocery store.

Stigma against dementia

Stigma is one of the biggest barriers for people living with dementia to live fully with dignity and respect. Help us fight stigma by learning more about its effects and taking steps to reduce its impact.

Learn more
Marilyn Taylor talking

What is Alzheimer's disease?

Alzheimer's disease is a chronic neurodegenerative disease that destroys brain cells, causing thinking ability and memory to deteriorate over time. Alzheimer's disease is not a normal part of aging, and is irreversible.

Learn more
Senior woman smiling