How Dementia Changes Over Time: The Different Stages

Dementia is progressive: symptoms usually start mildly and get worse over time, typically over several years. How fast this happens, and which symptoms appear, varies a great deal from one person to the next. This article explains the three broad stages most organisations use, what can speed up or slow down the changes, and when a sudden change needs a doctor. For a finer breakdown, see the 7 stages of dementia explained.

Mild cognitive impairment is not early dementia

Before the stages, one distinction matters. Mild cognitive impairment (MCI) means someone has more memory or thinking problems than others their age, but they can still manage their own care and daily routine, and they don't have the personality changes seen in dementia. That is what separates it from dementia, even in its early stage, where symptoms do start to interfere with daily life.

MCI doesn't always lead to dementia. The US National Institute on Aging estimates that 10 to 20% of people aged 65 or older with MCI develop dementia within a year, while in others the symptoms stay the same or improve. Some memory problems turn out to have treatable causes, which is one reason to see a doctor. Read more in what is mild cognitive impairment?

The three stages of dementia

The stages are also called mild, moderate and severe. They overlap, they don't always happen in the same order, and some people never have certain symptoms. Behavioural symptoms can fade in the later stages, while problems with memory, language and thinking tend to keep getting worse.

Early (mild) stage

Symptoms affect daily life, but the person can still do many things on their own or with a little help. Many people still live independently, drive, work and see friends. Common signs include:

• trouble finding the right word or remembering names
• forgetting something they have just read
• losing or misplacing valuable objects
• finding work or social situations harder to manage
• more difficulty planning and organising

This is the best time to make legal, financial and care plans, while the person can take a full part in the decisions.

Middle (moderate) stage

The middle stage is usually the longest and can last many years. Symptoms become more severe and wide-ranging, and the person needs help with basic tasks such as washing, dressing and using the toilet. Changes can include:

• forgetting events and parts of their own history, such as their address or phone number
• confusion about where they are or what day it is
• changes in mood, or withdrawing from people
• problems with bladder and bowel control
• disturbed sleep
• wandering, suspicion of others, delusions and repetitive behaviour

People can often still take part in everyday activities if tasks are broken down and simplified. Respite care and day centres give family carers a break.

Late (severe) stage

The person needs more constant care, often from professional carers, either at home or in a care home. In this stage:

• speech becomes very limited, often to a few words or phrases, and understanding others gets harder
• it becomes hard to show or say that they are in pain
• walking, sitting up, eating, drinking and swallowing become difficult, and falls are more likely
• incontinence is common
• infections, especially pneumonia, become more likely, and an infection can cause sudden confusion (delirium)

Care focuses on comfort and dignity. Hospice or end-of-life care can help both the person and their family.

How long each stage lasts

There is no set timetable. Some people need support soon after diagnosis, while others stay independent for several years. For Alzheimer's disease, the Alzheimer's Association gives an average survival of 4 to 8 years after diagnosis, though some people live as long as 20 years. See dementia life expectancy for other types.

What affects how fast dementia progresses

According to Alzheimer's Society, the main factors are:

• The type of dementia. Alzheimer's disease generally progresses more slowly than other types. See the stages of Alzheimer's disease.
• Age. Alzheimer's generally progresses more slowly in people over 65 than in younger people.
• Other health conditions. Heart disease, diabetes and high blood pressure can speed up the decline, especially if they aren't well managed.
• Delirium. A sudden illness that causes delirium can bring on a faster decline.

Things that may help someone keep their abilities for longer include accepting support, eating and sleeping well, not smoking or drinking heavily, staying physically, mentally and socially active, managing other health conditions, and keeping up with eye and hearing checks and recommended vaccinations such as flu and pneumococcal jabs.

When a change needs a doctor quickly

Dementia usually changes slowly. A rapid change over a day or two may be caused by a separate problem, such as an infection causing delirium, or a stroke. Contact a doctor or nurse promptly rather than putting it down to the dementia getting worse.

Planning ahead

Because abilities change over time, it helps to make legal, financial and end-of-life plans early, while the person can still take part in the decisions. Carers need support too: respite care and day centres give a break, and dementia charities run helplines for advice.