Dementia refers to a category of diseases that affects your cognitive functions, such as memory and behavior. Symptoms typically worsen over time and may progress in three stages.

There are three common stages of dementia: early, middle, and late. These highlight the progression and severity of symptoms.

Although most people with dementia progress through these stages, each person progresses at different speeds. For example, some people’s symptoms rapidly progress from mild to severe, while others may take years to move from one stage to another.

The average person with Alzheimer’s disease — which accounts for 60–80% of dementia cases — lives 4–8 years after receiving the diagnosis. That said, some people may live as many as 20 years after their diagnosis.

It’s estimated that 7 million people in the United States, ages 65 and older, had dementia in 2020. As life expectancy increases and the older population continues to grow, current trends suggest this number may nearly double by 2040.

The early stage of dementia, also known as mild dementia, is when a person starts to experience symptoms. These early signs may sometimes be hard to notice.

People in this stage may still function independently. But, they might also experience memory lapses that affect daily life, such as forgetting words or where things are.

Other common symptoms of early stage dementia include:

  • early memory loss, such as forgetting recent events
  • personality changes, such as becoming more subdued or withdrawn
  • getting lost or having trouble orientating themselves, even in familiar places
  • difficulty with problem-solving and complex tasks such as managing finances
  • trouble organizing or expressing thoughts

People in this early stage may also become irritated, anxious, or frustrated with their changing abilities.

It’s important to encourage people with dementia to do the tasks they can still do and help them with those they may be struggling with.

This stage typically lasts 2 years.

People in the middle stage of dementia, also known as moderate dementia, experience more noticeable symptoms. It will likely become harder to perform daily tasks, such as getting dressed, eating, and bathing.

In the middle stage, people might also require daily support from a caregiver at home. Alternatively, some people move to an assisted living home where dementia support is provided.

Common symptoms of middle stage dementia include:

  • increased confusion or poor judgment
  • increased forgetfulness, such as the names of friends and family members
  • increased short-term memory loss which may look like repeating themselves
  • increased long-term memory loss, such as forgetting events in the distant past
  • signs of delerium, paranoia, or hallucinations

Personality and behavioral changes, sometimes caused by agitation and unfounded suspicions, may also happen more frequently. This might include:

  • changes in sleep patterns, such as sleeping during the day and feeling restless at night
  • screaming, yelling, or shouting
  • confusion, disorientation, or restlessness at sundown (sundowning)
  • saying inappropriate things

This is typically the longest stage of dementia. On average, it lasts between 2 and 4 years.

People in the late stage of dementia, also known as severe dementia, may likely require full-time assistance at home or in a nursing home. In this stage, life expectancy is also greatly reduced.

Severe symptoms might include:

  • an inability to communicate, such as only being able to speak in their childhood language
  • an altered perception of time
  • needing full-time assistance with daily tasks, such as eating, dressing, and bathing
  • an inability to recognize faces of friends, family, or even themselves in a mirror
  • loss of physical abilities, such as walking, sitting, swallowing, or holding one’s head up
  • incontinence
  • increased susceptibility to infections, such as pneumonia

This is typically the shortest stage of dementia. It may last 1–2 years.

How fast do the stages of dementia progress?

Progressing through the three stages of dementia varies for each person.

According to the Alzheimer’s Society, each stage typically lasts:

  • early stage: 2 years
  • middle stage: 2–4 years
  • late stage: 1–2 years

What is the usual progression of dementia?

The progression of dementia depends on a few factors, such as the age when a person is diagnosed and the type of dementia they have. But dementia often progresses through three stages.

The early stage is when someone experiences mild symptoms, such as confusion and misplacing items. They are still largely independent at this stage.

The middle stage is when someone might need assistance to perform daily tasks, such as eating and bathing. Behavioral and personality changes become more significant, too.

The late stage is when symptoms are most severe. People often require full-time care and might be challenged by daily physical and cognitive tasks, such as walking, swallowing, and speaking.

What are the signs of dementia progressing?

As people move through the stages of dementia, their cognitive and physical abilities gradually decline.

Some signs and symptoms to look out for include:

  • wandering, getting lost, or being unable to orientate themselves
  • trouble communicating
  • memory loss and increased forgetfulness
  • trouble recognizing familiar landmarks and faces
  • increased agitation, aggression, or restlessness
  • trouble walking, eating, or controlling bowel movements

People with dementia may progress through these three common stages at different speeds and with differing symptoms. If you suspect you may be experiencing early symptoms of dementia, speak with a doctor.

While no cure is available for Alzheimer’s and other common dementias, early diagnosis can help people and their families plan for the future. Early diagnosis also allows people to participate in clinical trials. This helps researchers develop new treatments and eventually find a cure.