Alzheimer’s Disease

Alzheimer’s disease is a disease of the brain that gradually damages memory, thinking and judgement. It is the most common cause of dementia, though not the only one. Day to day it often shows up first as forgetting recent conversations, losing words mid-sentence, or finding a familiar task harder than before.

What Alzheimer’s disease is, and what it is not

Alzheimer’s disease and dementia are not two words for the same thing. Dementia is the umbrella term for the symptoms: memory loss and changes in thinking, language, mood or judgement severe enough to affect daily life. Alzheimer’s disease is one specific disease that causes them, and the Alzheimer Society of Canada says it accounts for 60 to 80% of dementia cases. Vascular and Lewy body dementia are others. Separate pages cover dementia and memory loss.

It is not a normal part of getting older, and it usually does not run in families: the Society says only about 2 to 5% of cases are familial. Nor does it follow a timetable. The Society calls the disease progressive and describes it in stages, while saying plainly that symptoms are difficult to predict.

Signs and symptoms

• Memory changes that affect daily life, such as not holding on to new information
• Trouble with tasks that were once routine, like cooking or managing money
• Difficulty finding common words, or using the wrong one so meaning is lost
• Losing track of the date, or becoming lost somewhere you know well
• Changes in mood, personality or judgement, and pulling back from people

The order and pace differ between people, and people close to you often notice first.

What raises the risk

Some things cannot be changed:

• Getting older. Risk roughly doubles every five years after 65, and about 1 in 4 Canadians over 85 lives with dementia
• Being a woman. An estimated 61.8% of people living with dementia in Canada in 2020 were female
• Family history and genetics, although only three genes directly cause the disease

Others can often be worked on, usually with support from a health care team:

• Blood pressure, type 2 diabetes, cholesterol, extra body weight and smoking
• Untreated hearing loss and vision loss, physical inactivity, heavy alcohol use, social isolation and depression
• Head injury, including from falls, and air pollution. The Society says around 40% of dementia cases may be linked to twelve key modifiable risk factors

How Alzheimer’s disease is diagnosed in Canada

Assessment usually begins with a family doctor or nurse practitioner, who takes a history from you and, with your permission, from someone close to you. Short memory and thinking tests such as the MoCA or the MMSE are common, alongside blood tests, brain imaging and a medication review to look for treatable causes such as thyroid problems, vitamin deficiency, infection and depression. Many people are then referred to a geriatrician, neurologist or memory clinic, because telling the causes of dementia apart changes what comes next. Where amyloid-targeting medicines are considered, assessment also involves an amyloid PET scan or a spinal fluid test plus ApoE testing, and access varies across the country.

Treatment and day-to-day management

Clinical research for Alzheimer’s Disease is enrolling. See the current studies ↓

No treatment stops or reverses Alzheimer’s disease. Care in Canada aims at symptoms, at the disease itself in early stages for some people, and at making daily life work. A health care team may discuss:

• Cholinesterase inhibitors, which the Alzheimer Society lists as donepezil, galantamine and rivastigmine, and memantine, which is authorised for middle to late stage disease
• Amyloid-targeting medicines for early disease only. Health Canada authorised lecanemab on 25 October 2025 and donanemab on 1 May 2026, both needing confirmed amyloid, infusions and scan monitoring. The Society says they slow progression rather than reverse it, and authorisation is not funding: coverage is decided separately, by province and by drug plan
• Reviewing other conditions that affect thinking: blood pressure, diabetes, hearing, vision, sleep, medicines
• Cognitive stimulation, physical activity, social contact and routines that ease daily tasks
• Support for the care partner: occupational therapy, home safety and driving assessment, home care, respite, and the Society’s First Link programme

Which of these fits is a decision for you, the people close to you and your own clinician.

When to talk to a doctor

• Call 911 for sudden confusion or memory loss, especially with weakness or numbness on one side, a drooping face, trouble speaking or a change in vision. These can be signs of a stroke, and time matters.
• Seek urgent care for confusion coming on over hours or days, especially with fever, a fall, a new medicine or a sudden behaviour change.
• Book an appointment if memory or thinking changes are worsening over months, or affecting driving, finances, medicines or safety at home. Care partners can raise concerns too.

Why clinical research matters for Alzheimer’s disease

Nothing available stops the disease. The medicines aimed at the disease itself apply only to early Alzheimer’s disease, only to some people who have it, and only with tests and monitoring that are not evenly available here. Diagnosis often comes late, and separating Alzheimer’s disease from other causes of dementia remains difficult. Research is looking at blood and imaging markers to identify it earlier, at further disease-modifying treatments, at agitation and disturbed sleep, and at risk reduction through exercise, blood pressure control and hearing care.

Studies are how those questions get answered. Taking part is voluntary, informed consent comes first, and you can stop at any time without affecting your regular care. Most memory studies ask you to bring someone who sees you often, and they consent separately. No one can say whether a study will help you personally.

Learn more from Canadian sources

• Alzheimer Society of Canada: Alzheimer’s disease
• Alzheimer Society: medications approved in Canada
• Alzheimer Society: risk factors and brain health
• Public Health Agency of Canada: dementia strategy