Stages of dementia

Most dementia, including Alzheimer's disease, gets worse slowly over years. Doctors and families often talk about it in stages: early, middle and late. Knowing the stages can help you plan ahead, find the right help at the right time, and make sense of the changes you see.¹

Stages are only a rough map. Each person moves through them in their own way and at their own speed. Stages also overlap, so a person may show signs of two stages at once.¹

The stages at a glance

This table shows the usual path in Alzheimer's disease, the most common cause of dementia. Click a stage name to read its full page.

Before symptoms: the preclinical stage

The disease starts long before anyone notices a problem. In Alzheimer's, amyloid (a sticky protein that builds up between brain cells) and tau (a protein that forms tangles inside brain cells) can begin to collect 10 years or more before memory changes appear.² Not everyone with these brain changes goes on to develop dementia.²

In 2024, an Alzheimer's Association expert group proposed defining Alzheimer's by these brain changes, which tests can now find, rather than by symptoms alone.⁴ The same group advised against testing people who have no memory or thinking problems, except as part of a research study.⁴ Read more on Before symptoms: preclinical Alzheimer's and Blood tests for Alzheimer's.

Early, middle and late stages

Early stage. The person can often live on their own and keep up many usual activities. Family and close friends may notice slips that others do not.¹ This is often when a diagnosis is made.² It is the best time to make legal, money and care plans while the person can take part. The newer anti-amyloid medicines are only for this stage and MCI. See Are anti-amyloid treatments right for us?.

Middle stage. This is usually the longest stage.¹ The person needs more help with daily tasks such as dressing, bathing and using the toilet. They may have sleep changes, get confused about where they are, become upset or suspicious, or wander.^1,2 Behavior changes often become the hardest part for families. Our Dementia symptoms and behaviors section explains why they happen and what helps.

Late stage. The person needs help with almost everything. They may stop talking in sentences, lose the ability to walk and sit up, and have trouble swallowing.^1,2 Pneumonia caused by food or liquid going into the lungs is a common cause of death.² Care now focuses on comfort. See Late-stage (severe) dementia and End of life in dementia.

Staging scales in plain words

Doctors and care teams use scoring tools to describe how far dementia has gone. You may hear these names in a clinic, a care facility or a hospice office.

GDS: the seven-stage scale

The Global Deterioration Scale (GDS) was created by Dr. Barry Reisberg at New York University. It splits the path of Alzheimer's into seven stages, from no problems at all to severe dementia.⁵

Source for this table: the Fisher Center summary of Dr. Reisberg's work.⁵

FAST: a scale built on everyday abilities

The Functional Assessment Staging Tool (FAST), also from Dr. Reisberg, looks only at what the person can still do in daily life.⁸ Its stages match the GDS stages. Stages 6 and 7 are split into smaller steps (6a to 6e and 7a to 7f). For example, needing help with dressing usually comes before needing help with bathing, and losing speech comes before losing the ability to walk.^5,8

FAST matters most near the end. Medicare's usual guide for hospice in dementia looks for FAST stage 7 or beyond, plus at least one serious health problem in the past year. Examples are aspiration pneumonia, a serious kidney infection, blood infection, several bedsores, fevers that come back after antibiotics, or not eating or drinking enough with large weight loss.⁸ Predicting time left in severe dementia is hard, so these guides are not perfect.⁸ See Hospice care for dementia.

CDR: the Clinical Dementia Rating

The Clinical Dementia Rating (CDR) is maintained by the Knight Alzheimer Disease Research Center at Washington University in St. Louis. A trained rater interviews the person and a family member or friend who knows them well.⁷ The interview takes about 30 minutes.⁶

The CDR rates six areas: memory, knowing time and place, judgment and problem solving, community activities, home life and hobbies, and personal care.⁷ Each area gets a score: 0 (normal), 0.5 (questionable), 1 (mild), 2 (moderate) or 3 (severe).⁶

Adding the six scores gives the "sum of boxes" (CDR-SB), from 0 to 18. A higher number means more problems.⁶ Drug studies, including the trials of lecanemab and donanemab, often report results on this scale.

Source for this table: InformedHealth.org (IQWiG).⁶

The newer biology-based stages

The 2024 Alzheimer's Association criteria add two kinds of staging. Biological stages A to D describe how much amyloid and tau show on brain scans. A separate clinical scale runs from stage 1 (no symptoms) to stage 6 (severe dementia).⁴ These stages are mostly used in research and specialty clinics for now. The two often do not match, because other problems, such as small strokes, can add to symptoms.⁴

How long does each stage last?

There is no fixed timeline. On average, people 65 and older live 4 to 8 years after an Alzheimer's diagnosis, and some live 20 years.³ A lot of that time can be in the later stages. For a person who lives with Alzheimer's dementia from age 70 to 80, about 40% of those years are spent in the severe stage.³

Dr. Reisberg's research gave rough average lengths for each GDS stage.⁵

• Stage 4 (mild dementia): about 2 years
• Stage 5 (moderate dementia): about 1.5 years
• Stage 6 (moderately severe): about 2.5 years
• Stage 7 (severe): often several years in total, step by step

Real life often looks different. Many things change the pace:

• Type of dementia. Vascular dementia (caused by reduced blood flow to the brain) can start suddenly, then get worse over time, sometimes with short periods of improvement.⁹ Other types, such as Lewy body dementia and frontotemporal dementia, follow their own patterns. See Types of dementia.
• Mixed causes. Some people have more than one brain problem, such as Alzheimer's plus small strokes. This can make symptoms worse than brain scans alone would suggest.⁴ See Mixed dementia.
• Other health and life factors. How long a person lives with dementia also depends on other factors in their health and life.¹ Hospital stays can be hard on people with dementia. See Hospital stays and emergency rooms.

Using the stages to plan

Stages work best as a planning tool, not a countdown.

• Early on: Get a clear diagnosis, ask about treatment, and sign a power of attorney and advance directive while the person can still decide. Start the talk about driving.
• In the middle: Look at adult day care, in-home care and respite care. Make the home safer. Build a care circle so one person does not carry it all.
• Later: Learn about palliative care and hospice, and decide in advance about feeding tubes and hospital care.

Caring for someone through every stage is long and tiring work. Please look after your own health too. Our caregivers page and Caregiver stress and burnout can help.

Pages in this section

• Before symptoms: preclinical Alzheimer's
• Early-stage (mild) dementia
• Middle-stage (moderate) dementia
• Late-stage (severe) dementia

In this section

Education only. This page is general information written from the sources listed. It is not medical, legal or financial advice and does not replace a doctor, therapist or lawyer who knows your situation. How we write and check pages.