Alzheimer’s disease is a neurological condition that causes a decline in thinking skills and memory. There is currently no cure, but there are ways to support a person with medication and other strategies.

Alzheimer’s disease is the most common type of dementia. It accounts for around 60% to 80% of cases of dementia in the United States. For people who develop it, the condition typically starts at age 65 years or older.

This article provides an overview of Alzheimer’s disease, including its symptoms, causes, and possible treatment options.

Alzheimer’s disease is a condition that affects the brain. Symptoms are mild at first and become more severe over time. It is named after Dr. Alois Alzheimer, who first described the condition in 1906Trusted Source.

Common symptoms of Alzheimer’s disease include memory loss, language problems, and impulsive or unpredictable behavior.

One of the underlying biological changes of the condition is the presence of plaques and tangles in the brain. Another feature is a loss of connection between the nerve cells, or neurons, in the brain.

These changes prevent information from passing between different areas of the brain or between the brain and the muscles or organs.

As symptoms worsen, it becomes harder for people to remember recent events, to reason, and to recognize people they know. Eventually, a person with Alzheimer’s disease may need full-time assistance.

What is the difference between dementia and Alzheimer’s?

“Dementia” is an umbrella term for a range of conditions that involve a loss of cognitive functioning. Alzheimer’s disease is the most common type.

Other types of dementia include:

It is possible to have more than one type of dementia.

Alzheimer’s disease ranges from mild to severe. The sections below discuss the stages of Alzheimer’sTrusted Source and some of their symptoms.

Mild Alzheimer’s disease

People with mild Alzheimer’s disease develop memory problems and thinking difficulties that may include:

  • taking longer than usual to perform daily tasks
  • difficulty handling money or paying the bills
  • wandering and getting lost
  • experiencing personality and behavior changes, such as getting upset or angry more easily, hiding things, or pacing

Moderate Alzheimer’s disease

In moderate Alzheimer’s disease, the parts of the brain responsible for language, senses, reasoning, and consciousness become damaged. This can lead to:

  • greater memory loss and confusion
  • difficulty recognizing friends or family
  • an inability to learn new things
  • difficulty performing tasks with several stages, such as getting dressed
  • difficulty coping with new situations
  • impulsive behavior
  • hallucinations, delusions, or paranoia

Severe Alzheimer’s disease

In severe Alzheimer’s disease, plaques and tangles are present throughout the brain, causing the brain tissue to shrink substantially. This can lead to:

  • an inability to communicate
  • dependency on others for care
  • being unable to leave bed all or most of the time

Learn more about the stages of Alzheimer’s.

Alzheimer’s disease is a progressive condition, meaning the symptoms get worse over time. Memory loss is a key feature, and this tends to be one of the first symptoms to develop.

Symptoms appear gradually, over months or years.

If similar symptoms develop over hours or days, this could indicate a stroke, and a person requires immediate medical attention.

Symptoms of Alzheimer’s disease include:

  • Memory loss: A person may have difficulty taking in new information and remembering information. This can lead to:
    • repeating questions or conversations
    • losing objects
    • forgetting about events or appointments
    • wandering or getting lost
  • Cognitive deficits: A person may experience difficulty with reasoning, complex tasks, and judgment. This can lead to:
    • a reduced understanding of safety and risks
    • difficulty with money or paying bills
    • difficulty making decisions
    • difficulty completing tasks that have several stages, such as getting dressed
  • Problems with recognition: A person may become less able to recognize faces or objects or less able to use basic tools, even if they can see them clearly.
  • Problems with spatial awareness: A person may have difficulty with their balance, trip over, or spill things more often, or they may have difficulty orienting clothing to their body when getting dressed.
  • Problems with speaking, reading, or writing: A person may develop difficulties with thinking of common words, or they may make more speech, spelling, or writing errors.
  • Personality or behavior changes: A person may experience changes in personality and behavior that include:
    • becoming upset, angry, or worried more often than before
    • a loss of interest in or motivation for activities they usually enjoy
    • a loss of empathy
    • compulsive, obsessive, or socially inappropriate behavior

Although Alzheimer’s disease usually affects older adults, it does not only occur in this group. People can develop the condition in their 40s or 50s. In rare casesTrusted Source, it may develop in a person’s 30s. This is known as early onset Alzheimer’s disease.

According to the Alzheimer’s Association, it is unclear how many people have early onset Alzheimer’s disease of the 7 million in the United States living with Alzheimer’s. However, it is much less common for the condition to develop at a younger age.

In many cases, doctors do not know why younger people develop this condition. Several rare genes can cause the condition. When there is a genetic cause, it is known as familial Alzheimer’s disease.

There is no single test for Alzheimer’s disease. If a doctor suspects the presence of the condition, they will ask the person about their symptoms, experiences, and medical history.

Sometimes, they will ask friends and family, as they may notice the symptoms of dementia before the person themselves.

The doctor may also perform or order the following tests:

  • cognitive and memory tests to assess the person’s ability to think and remember
  • neurological function tests to test their balance, senses, and reflexes
  • blood or urine tests
  • a CT scan or MRI scan of the brain
  • genetic testing

In some cases, genetic testing may be appropriate, as the symptoms of dementia can be relatedTrusted Source to an inherited condition, such as Huntington’s disease. There also some specific genes with links to Alzheimer’s, such as the APOE gene.

Testing for relevant genes early could indicate the likelihood of someone having or developing the condition.

There is no known cure for Alzheimer’s disease. It is not possible to reverse the death of brain cells.

However, treatments can relieve its symptoms and improve quality of life. Some emerging treatments may even slow disease progression.

The options include:

Medications to treat symptoms

Drugs known as cholinesterase inhibitors can ease cognitive symptoms in Alzheimer’s disease, including memory loss, confusion, altered thought processes, and judgment problems. They improve neural communication across the brain and slow the progression of these symptoms.

The Food and Drug Administration (FDA)Trusted Source has approved the following cholinesterase inhibitors for Alzheimer’s disease:

  • galantamine (Razadyne) to treat mild to moderate stages
  • rivastigmine (Exelon) to treat mild to moderate stages
  • donepezil (Aricept) to treat all stages

Another drug, memantine (Namenda), has FDA approval to treat moderate to severe Alzheimer’s disease. A combination of memantine and donepezil (Namzaric) is also available.

For people who experience changes to their mood or mental health conditions, doctors may suggest antidepressants or antipsychotics.

Disease-modifying drugs

There are now treatments that can slow the progression of Alzheimer’s disease. They include:

  • lecanemab (Leqembi), which slowed progression by 25% in a phase 3 clinical trial
  • donanemab (Kisunla), which slowed cognitive decline by 32% in a review of previous studies
  • aducanemab (Aduhelm), which has only had modest effectsTrusted Source on cognition and is still undergoing testing

All drugs for Alzheimer’s have risks and can cause side effects. People can discuss these in detail with their doctor.

Other treatments

Other strategies that may help with symptoms include:

  • creating a safe, familiar living environment
  • removing objects that could be harmful or cause injury
  • sticking to a routine
  • getting exposure to daylight and having a regular bedtime to help with sleep
  • getting regular aerobic exercise, which may slowTrusted Source Alzheimer’s progression

The Alzheimer’s Association offers a list of helpful coping tips for caregivers.

Alzheimer’s and dementia resources

To discover more evidence-based information and resources for Alzheimer’s and dementia, visit our dedicated hub.

Like all types of dementia, Alzheimer’s developsTrusted Source due to the death of brain cells.

In a person with Alzheimer’s, the brain tissue has fewer and fewer nerve cells and connections. Tiny deposits, known as plaques and tangles, build up on the nerve tissue.

Plaques develop between the dying brain cells. They consist of a protein known as beta-amyloid. Meanwhile, the tangles occur within the nerve cells. They consist of another protein known as tau.

Researchers do not fully understand why these changes occur.

The Alzheimer’s Association has produced a visual guide to show what happens in the process of developing Alzheimer’s disease.

The risk factors for Alzheimer’s disease fall into two categories: modifiable and unmodifiable.

Unmodifiable risk factors for Alzheimer’s disease includeTrusted Source things a person cannot change, such as:

  • age
  • having a family history of Alzheimer’s disease
  • having certain genes

Modifiable factors are things a person can change or manage, such as:

Other factors that may increase the risk of Alzheimer’s include traumatic brain injuries and depression.

People may be able to reduce their risk of Alzheimer’s disease by:

  • getting regular aerobic exercise
  • eating a balanced diet
  • maintaining a moderate weight
  • keeping the brain active throughout life with hobbies such as reading or playing musical instruments
  • managing any chronic conditions, such as diabetes or high blood pressure

Below are some common questions about Alzheimer’s disease.

What age can Alzheimer’s start?

Alzheimer’s usually affects people ages 65 years and overTrusted Source, but it can start as early as the 30s. This is rare, though, as older age is one of the main risk factors of Alzheimer’s disease.

What are the 7 stages of Alzheimer’s?

The seven clinical stagesTrusted Source of Alzheimer’s disease are:

  • Stage 1: A person does not have any symptoms, but pathological changes are happening in the brain.
  • Stage 2: Prodromal stage; mild memory loss, but generally this is indistinguishable from normal forgetfulness.
  • Stage 3: Progression into mild cognitive impairment. People may get lost or have difficulty in finding correct wording.
  • Stage 4: Moderate dementia; poor short-term memory. People forget some of their personal history.
  • Stage 5: Cognition continues to decline, and people need help in their daily lives. They experience confusion and forget many personal details.
  • Stage 6: Severe dementia; people require constant supervision and care. They do not recognize many of their family and friends and have personality changes.
  • Stage 7: People are nearing death. They show motor symptoms, have difficulty communicating, experience incontinence, and require assistance in feeding.

What is the life expectancy for Alzheimer’s?

According to the Alzheimer’s Association, a person with the condition will live 4 to 8 years after diagnosis, on average. Depending on other factors, though, they may live as long as 20 years.

Alzheimer’s disease is a neurodegenerative condition. A buildup of plaques and tangles in the brain, along with cell death, causes memory loss and cognitive decline.

There is currently no cure, but drugs and other treatments can help slow or ease the cognitive, emotional, and behavioral symptoms and improve the person’s quality of life.