Dementia is marked by a severe decline in cognitive functions, such as thinking, reasoning, and remembering, to the extent that it interferes with the person's daily life.

Dementia typically affects older adults, but it is not a normal part of the aging process. While some amount of forgetfulness is normal with age, dementia is a severe disorder that can affect the person's ability to function on a daily basis.

According to the National Institute on Aging, about one-third of all people above the age of 85 have some form of dementia. Dementia can stem from various causes, the most common being Alzheimer's disease. Some of the other causes include Parkinson's disease, Lewy body dementia, and frontotemporal dementia.

Dementia progresses in stages, ranging from mild to severe. In 1982, Dr. Barry Reisberg created the Global Deterioration Scale (GDS), which consists of seven stages, to help clinicians categorize the progression of dementia.

This article explores the seven stages of dementia so you know what to expect if you or a loved one has been diagnosed with it.

The stages are as follows:

Stages 1 to 3 are the pre-dementia stages, whereas stages 4 to 7 are the dementia stages. Clinicians typically compare the person's symptoms to the criteria listed for each stage and use their judgment to determine which stage the patient is at.

The seven stages of dementia are outlined below.

At this stage, the person can function normally and exhibits no signs of memory loss, confusion, or cognitive impairment.

However, the structure and functioning of their brain may have started to deteriorate as the neurons (nerve cells) in their brain start to lose connection with other brain cells and die.

The person starts to experience occasional lapses of memory, such as:

At this stage, the symptoms are unlikely to affect the person’s work or social interactions. 

In fact, the symptoms may even be too mild to detect in a clinical interview with a healthcare provider, as the person may be able to adequately perform memory tests during the interview. 

This is the stage at which cognitive impairment starts to become more noticeable to the patient, their friends, family members, and colleagues.

The person may start to show symptoms such as:

The person may start to feel anxious as their symptoms begin to become apparent and interfere with their ability to function. 

In this stage, the person will exhibit a definitive decline in cognitive ability in a clinical interview.

Some of the symptoms of this stage may include:

At this stage, the person will likely still be able to recognize loved ones’ names and faces and navigate familiar places. However, they may start to avoid challenging situations to prevent anxiety and hide their distress from others.

From this stage onward, the person may no longer be able to function without some assistance. 

These are some of the symptoms of this stage:

In this stage, the person can likely still remember their own name and the names of their spouse and children, but they may struggle with recalling their grandchildren's names. They may be able to eat and use the bathroom without assistance but may need help with tasks such as deciding what to wear.

At this stage, the person may require a high degree of care, as they may have symptoms such as:

The person is also likely to experience emotional and personality changes, such as:

During this stage, the person is likely to still remember their name and distinguish between familiar and unfamiliar people in their environment. They will probably need assistance with daily living activities and may experience incontinence and sleep-related difficulties.

In the final stage, the brain appears to lose its connection to the body and becomes incapable of telling it what to do. 

The person is likely to progressively lose their motor skills and the ability to speak. They may only be able to utter unintelligible sounds or words, if at all. They will need assistance with all personal care tasks, such as eating, walking, and using the bathroom.

Dementia is a challenging condition to live with because it increasingly affects a person’s mental faculties and ability to function. Being aware of how the condition progresses can be useful because it can help you take steps to slow it down, understand what to expect, and prepare for it.