The Stages of Alzheimer's Disease


Alzheimer's disease is the most common form of dementia in individuals older than 65 years and affects more than 5 million Americans.

Alzheimer’s disease is the most common form of dementia in individuals older than 65 years and affects more than 5 million Americans, according to the Alzheimer’s Association.1 Dementia is a general term for a decline in mental ability severe enough to interfere with daily life.

Alzheimer’s progresses slowly in 3 stages: an early stage with few symptoms, a middle stage of mild mental impairment, and a final stage of Alzheimer’s dementia (Table). These stages are general descriptions, as each individual with Alzheimer’s experiences it in a unique way. Mental, physical, and functional phases often overlap, the time in each stage varies widely from patient to patient, and not every patient experiences all Alzheimer’s symptoms.2

Memory problems and changes in behavior and thinking are common as people age, so tests are needed to rule out other causes of symptoms that appear to be related to Alzheimer’s. Some conditions (such as stroke, tumor, Parkinson’s disease, sleep disturbances, adverse effects of medication, infections, or non-Alzheimer’s dementia) can mimic the symptoms of Alzheimer’s disease, but many of these conditions are treatable and possibly reversible.

The amount of time an individual can live with Alzheimer’s can range from 3 or 4 years, if older than 80 years when given a diagnosis, to as long as 10 years or more if younger than 80 years.3 Alzheimer’s can only be definitively diagnosed after death, however, by linking symptoms with examination of brain tissue in an autopsy.

Stage 1: Mild/Early (Lasts 2 to 4 Years)

Alzheimer’s disease begins slowly and initially involves the parts of the brain that control thought, memory, and language. In the very early stages, minor memory lapses or losing things around the house may be the only symptoms. Toward the end of the first stage, friends and family may recognize there is a problem. They may begin to notice their loved one frequently repeating questions, having difficulty finding the right word in conversations, and losing understanding of language. Over time, the disease deprives individuals of more memory, particularly the ability to remember new information, such as recent conversations or events. Based on performance on memory and mental tests, a physician will be able to detect impaired mental function at this stage.4

Stage 2: Moderate/Middle (Lasts 2 to 10 Years)

Moderate Alzheimer’s can last for many years. During the moderate/ middle stage, brain function gets worse, affecting areas of the brain that control language, reasoning, sensory processing, and thought. The symptoms of moderate Alzheimer’s disease are mostly an increase in the severity of stage 1 symptoms. Professional and social functioning continue to deteriorate because of increasing problems with memory, logic, and speech.

The signs of the disease become more pronounced, and behavioral problems often occur. Individuals have greater difficulty performing tasks and begin to forget some details about their life. Affected individuals may still know their family members and some details about their past, especially their childhood and youth. Symptoms may include mood and behavior changes, social withdrawal, confusion, changes in sleep patterns, and an increased risk of wandering and becoming lost.5

Information, skills, and habits learned early in life, such as the ability to read, dance, sing, enjoy music, and hobbies, are among the last abilities to be lost as the disease progresses. The part of the brain that stores this information tends to be affected later in the course of the disease. Making the most of these abilities can help maintain quality of life, even in the moderate phase of the disease.

Stage 3: Severe/Late (Lasts 1 to 3+ Years)

In the last stage of Alzheimer’s, nerve cells in the brain are extensively damaged, causing a severe decline in vocabulary, emotions, and the connection of the brain to body parts. Full-time care is required as patients lose the ability to walk, sit up straight, hold up their head, and smile. It is not possible for patients to move the hand to the mouth, place one foot in front of the other, or urinate on their own. Speech becomes severely limited.

Death often occurs when the body can no longer fight off infection or because the organs begin to break down. Pneumonia is one of the most frequent causes of death in late-stage Alzheimer’s disease.6 In patients who do not succumb to infection or other conditions that are not directly related to Alzheimer’s disease, death usually occurs when the brain can no longer control the body and organs.

Reasons for Hope

Although the onset of Alzheimer’s disease cannot yet be stopped or reversed, an early diagnosis can allow individuals the opportunity to live well for as long as possible and plan for the future. Current treatment approaches focus on helping patients maintain mental function, manage behavioral symptoms, and improve the symptoms of disease. In the future, therapies may be available that target specific genetic, molecular, and cellular mechanisms so that the underlying cause of the disease can be stopped or prevented.

Beth is a clinical pharmacist and medical editor residing in northern California.


  • Alzheimer’s disease & dementia. Alzheimer’s Association website. alzheimers_disease_1973.asp. Accessed February 15, 2016.
  • Alzheimer’s disease. website. dementia/alzheimers-disease. htm. Accessed February 15, 2016.
  • About Alzheimer’s disease: Alzheimer’s basics. National Institute on Aging website. alzheimers-basics. Accessed February 15, 2016.
  • What are the 7 stages of Alzheimer’s disease? website. alzheimers. net/stages-of-alzheimers-disease. Accessed February 15, 2016.
  • Stages of Alzheimer’s. Alzheimer’s Association website. disease_stages_of_alzheimers.asp. Accessed February 15, 2016.
  • The later stages of dementia. Alzheimer’s Society website. alzheimers. php?documentID=101. Accessed February 15, 2016.

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