What Is Alzheimer’s Disease?
Neurological DisordersAlzheimer’s Disease

What Is Alzheimer’s Disease?

What Is Alzheimer’s Disease?
Everyday Health
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Updated on March 5, 2026
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Alzheimer’s disease is a progressive, irreversible brain disorder that slowly erodes memory, cognition, and the ability to think and reason. It’s the most common form of dementia among older adults. Most people with this disorder are 65 or older, but it can also begin at an earlier age.

Alzheimer’s disease causes nerve cells (neurons) to stop functioning, lose their connections with other neurons, and eventually deteriorate and break down. While there is currently no cure for Alzheimer’s, there are medications that improve symptoms and delay progression into the later stages of the disease.

Scientists are working to understand the biological pathways behind Alzheimer’s disease, with the goal of finding new and better treatments and ways to further delay or prevent Alzheimer’s disease.

Signs and Symptoms of Alzheimer’s Disease

While a certain amount of forgetfulness — occasionally misplacing things, failing to recall a specific word — is a normal part of aging, certain types of memory loss may be an indicator of early-stage Alzheimer’s disease.

Scientists have identified a condition called mild cognitive impairment (MCI) that for some (not all) people is an early sign of Alzheimer’s disease. MCI involves problems with memory or mental function that are noticeable to the person affected but not serious enough to interfere with everyday life.

People with MCI may be at higher risk of developing Alzheimer’s or other forms of dementia than people who don’t have MCI. But MCI doesn’t always progress, and some people even get their cognitive abilities back.

Signs and Symptoms of Early-Stage Alzheimer’s Disease

Symptoms of Alzheimer’s disease are generally mild at first, but they become more noticeable as the disease progresses. The person may begin having difficulty with:

  • Memory Losing items like keys around the house, forgetting a friend’s name or a recent conversation, getting lost in a familiar place
  • Speech Repeating oneself or struggling to follow a conversation
  • Visual Perception Difficulty seeing things in three dimensions or judging distances
  • Concentrating, Organizing, or Planning Struggling to make decisions, solve problems, or complete multistep tasks, such as cooking a meal
  • Orientation Getting confused about location, time, or date
  • Mood Feeling anxious, depressed, or irritable

Signs and Symptoms of Later-Stage Alzheimer’s Disease

As the disease becomes more advanced, symptoms seen in early-stage disease become more pronounced. People may also experience:

  • Delusions For instance, believing without reason that someone is stealing from them
  • Uncharacteristic Behavior Exhibiting aggression or agitation, calling out, or having disturbed sleep patterns
  • Difficulty Walking Becoming bedridden or wheelchair-bound and requiring round-the-clock care to help with daily tasks
  • Increased Difficulty Communicating Failing to understand what others are saying, not being able to respond, and largely ceasing to speak

Causes and Risk Factors of Alzheimer’s Disease

Researchers believe that the vast majority of Alzheimer’s cases are due to some combination of genetics, lifestyle, and environment. Risk factors include:

  • Age Alzheimer’s disease is not a normal part of aging, but the risk for it increases with age beyond 65.
  • Family History Having a first-degree relative (such as a parent or sibling) with the disease is a strong risk factor. This may reflect shared genetics, environmental factors, or both.
  • Genetics One gene variant, called APOE-e4, appears to significantly raise a person’s Alzheimer’s risk. But some people with APOE-e4 never develop Alzheimer’s, while others who develop Alzheimer’s don’t have the gene variant.
Risk factors for Alzheimer’s that may be somewhat under a person’s control include:

  • Head Injury Researchers have identified a link between traumatic brain injury and different types of dementia, including Alzheimer’s. Wearing a seat belt in a car or a helmet while playing certain kinds of sports or minimizing the risk of falling in your home can offer protection.
  • Cardiovascular Problems When your heart or blood vessels are damaged or diseased, your body is unable to pump enough blood to your brain, depriving cells of the oxygen they need to function. Conditions like heart disease, stroke, high blood pressure, high cholesterol, and diabetes may raise your Alzheimer’s risk.
  • Poor Overall Health Researchers believe that poor overall health — linked to habits like smoking, being sedentary, or following an unhealthy diet — may increase Alzheimer’s risk.
Perspectives
Portrait of a person
Paula
Living with Alzheimer’s disease
“Having a physical illness — I have had many in my life. But the idea that I could lose my brain this way is like this whole different story. Because your brain is really who you are.”
Transcript Available

How Is Alzheimer’s Disease Diagnosed?

There is no single test that can determine whether a person has Alzheimer’s disease. Instead, doctors may use a number of diagnostic methods:

  • Medical history, including inquiring about health issues that have affected family members
  • Physical exam and diagnostic tests to help identify ailments that may cause dementia-type symptoms, such as depression, untreated sleep apnea, delirium, certain vitamin deficiencies, side effects of medication, thyroid problems, or excess alcohol use)
  • Neurological exam, which tests strength, sensation, reflexes, and eye movements
  • Mental status tests, which may include memory assessments and other cognitive skills
  • Brain imaging, such as a magnetic resonance imaging or computerized tomography scan, which may be used to rule out the presence of a tumor or another abnormality that could be responsible for Alzheimer’s-like symptoms

Treatment and Medication Options for Alzheimer’s Disease

While there is currently no cure for Alzheimer’s disease, certain treatments can slow cognitive decline for a limited time, help manage behavioral symptoms, and provide relief for symptoms like anxiety and depression.

Disease-Modifying Drugs

Two drugs, lecanemab (Leqembi) and donanemab (Kisunla), address the underlying biology of the disease by removing beta-amyloid clumps from the brain. The drugs are approved by the FDA and have been shown to slow the progression of cognitive decline when they’re started in early-stage Alzheimer’s. Both can cause brain swelling and bleeding as a side effect.

Medications for Symptoms

A number of other drugs are approved to treat cognitive symptoms of Alzheimer’s disease. These drugs are believed to work by altering levels of neurotransmitters in the brain. These include:

  • Donepezil (Aricept)
  • Galantamine (Razadyne)
  • Benzgalantamine (Zunveyl)
  • Memantine (Namenda)
  • Rivastigmine (Exelon)
  • Donepezil and memantine (Namzaric)

Doctors may also prescribe drugs for people experiencing behavioral symptoms of Alzheimer’s, targeting conditions such as depression, aggression, restlessness, and anxiety.

The drug brexpiprazole (Rexulti) is approved to treat agitation in Alzheimer’s, and the drug suvorexant (Belsomra) is approved to treat insomnia in people with Alzheimer’s.

Research efforts on new Alzheimer’s treatments have been frustrating, with promising drug candidates often failing in clinical trials.

 But scientists are continuing to explore new interventions.

Nondrug Approaches

Whether or not a person with Alzheimer’s is being treated with medications, they can generally benefit physically and mentally from involvement in support groups, social outings geared toward people with dementia, and activities like dancing that combine social, mental, and physical engagement. In earlier stages of the disease, meeting with a psychotherapist may be helpful for coming to terms with the diagnosis and improving coping skills.

Complementary Treatments

Despite the growing number of herbal remedies, dietary supplements, and “medical foods” aimed at people with Alzheimer’s, there is no scientific proof that any of these products work.

For instance, some people with Alzheimer’s disease consume coconut oil based on the theory that the caprylic acid in the oil can provide energy to brain cells that are no longer able to metabolize glucose. But there has been no research confirming that this helps cognition.

There is evidence, though, that following an overall healthy diet may reduce the risk of developing Alzheimer’s disease and other forms of dementia.

Lifestyle Changes and Prevention for Alzheimer’s Disease

Can a healthy lifestyle reduce Alzheimer’s risk? A growing body of research suggests it can. One study found that even people at high genetic risk of dementia could reduce their risk by pursuing a healthy lifestyle that involved:

  • Not smoking
  • Exercising regularly
  • Eating a healthy diet
  • Consuming alcohol only moderately
You may also reduce your Alzheimer’s and dementia risk by being socially active, maintaining a healthy body weight, and getting quality sleep.

Prognosis of Alzheimer’s Disease

There’s no cure for Alzheimer’s disease, and current treatments can only slow its progression — meaning that the person’s cognitive decline continues until death. But especially in its earlier stages, Alzheimer’s related cognitive decline may be slowed by lifestyle measures like staying physically active and socially engaged and following a healthy diet.

Perspectives
Portrait of a person
Paula
Living with Alzheimer’s disease
“You know, I am not my … Alzheimer's. Paula is still here. I'm not just somebody with Alzheimer's.”
Transcript Available

Complications of Alzheimer’s Disease

In the advanced stages of Alzheimer’s disease, complications from severe loss of brain function can include:

Support for Alzheimer’s Disease

Alzheimer’s Association

This nonprofit organization works on global, national, and local levels to provide care and services for people affected by Alzheimer’s and other types of dementia. It’s also a leader in research and advocacy. Call 800-272-3900 (24/7 helpline).

Eldercare Locator

This public service of the U.S. Administration for Community Living links older adults and their families with state and local agencies and community-based organizations that provide services. Call 800-677-1116.

CaringKind

This advocacy group is a leading expert on Alzheimer’s and dementia caregiving. They have a helpline staffed by dementia specialists, individual and family consultations, a large network of support groups, education programs, early-stage services, and a wanderer’s safety program. Call 646-744-2900.

Alzheimers.gov

This website from the National Institute on Aging offers general information about participating in Alzheimer’s research, as well as a search function to see if you or a loved one might be eligible to participate in a study.

Well Spouse Association

This nonprofit group aims to help spouses and partners of people with dementia and other chronic health conditions find support groups, with the aim of lightening the emotional burden and sharing strategies. Call 732-577-8899.

Perspectives
portrait of a person
Rena
Caring for her sister with Alzheimer’s disease
“I am in a caregiver role in a way I never have been. I wanted my relationship with Paula to be as much as it was before as possible.”
Transcript Available

The Takeaway

  • Alzheimer’s disease is a progressive, irreversible type of dementia that gradually destroys memory, thinking skills, and the ability to function independently.
  • Symptoms worsen over time, starting with mild memory loss and confusion (sometimes preceded by mild cognitive impairment) and progressing to severe cognitive decline, behavioral changes, communication difficulties, and a loss of physical abilities.
  • There is no cure, but certain medications and lifestyle measures may slow progression or ease symptoms. Risk increases with age, genetics, and lifestyle factors, while healthy habits may help reduce risk.

FAQ

What’s the difference between Alzheimer’s disease and dementia?

Dementia is a broad term that refers to significant cognitive impairment from any cause. Alzheimer’s disease is the leading cause of dementia among older adults and involves a specific pattern of changes in the brain that leads to cognitive decline.

Older age is the most clearly established risk factor for Alzheimer’s. It’s much more common in adults age 65 and older, and the risk increases with age within this group. Other factors that may affect your risk for Alzheimer’s include a family history of the disease, your cardiovascular health, and lifestyle measures in areas like nutrition, physical activity, and sleep quality.

The development of Alzheimer’s disease can take decades, so it’s unlikely you’ll experience sudden changes in your cognitive abilities. But people who are developing Alzheimer’s may first experience greater forgetfulness, followed by more significant changes in memory, speech, judgment, ability to concentrate, and the awareness of time and location.

While there are treatments for Alzheimer’s disease, none of them can stop the condition. They can, at best, slow down the rate of cognitive decline and are most effective in early stages of Alzheimer’s. But as researchers learn more about the disease, they’re hopeful that more effective treatments and, eventually, a cure will emerge.

You may be able to reduce your risk for Alzheimer’s by taking care of your health in general — following a healthy lifestyle and effectively managing conditions like high blood pressure and diabetes. But there is no clear path to ensure that you don’t develop Alzheimer’s disease.

Resources We Trust

EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
  1. Alzheimer’s Disease Fact Sheet. National Institute on Aging. April 5, 2023.
  2. Mild Cognitive Impairment (MCI). Mayo Clinic. October 24, 2024.
  3. Alzheimer’s Disease. Cleveland Clinic. February 19, 2025.
  4. What Are the Signs of Alzheimer’s Disease? National Institute on Aging. October 18, 2022.
  5. Alzheimer’s Disease. Mayo Clinic. November 8, 2024.
  6. What Are the Causes and Risk Factors of Alzheimer’s and Other Dementias? Alzheimer’s Association.
  7. Medical Tests for Diagnosing Alzheimer’s. Alzheimer’s Association.
  8. How Is Alzheimer’s Disease Treated? National Institute on Aging. September 12, 2023.
  9. Watt JA et al. Disease-Modifying Drugs for Alzheimer Disease: Implications for People in Canada. Canada Medical Association Journal.
  10. Medications for Memory, Cognition, and Dementia-Related Behaviors. Alzheimer’s Association.
  11. Goldman B. One Step Back: Why the New Alzheimer’s Plaque-Attack Drugs Don’t Work. Stanford Medicine. March 13, 2024.
  12. Treatment and Support of Alzheimer’s Disease. Alzheimer’s Society.
  13. Alternative Treatments. Alzheimer’s Association.
  14. Lou IX et al. Effect of Nutrition in Alzheimer’s Disease: A Systematic Review. Frontiers in Neuroscience. May 3, 2023.
  15. Laurida I et al. Association of Lifestyle and Genetic Risk With Incidence of Dementia. JAMA. July 14, 2019.
  16. Alzheimer’s Stages: How the Disease Progresses. Mayo Clinic. May 9, 2025.
  17. Common Medical Problems in Alzheimer’s Disease: Information for Caregivers. National Institute on Aging. July 11, 2024.
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Jessica Baity, MD

Medical Reviewer
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Jessica Baity, MD, is a board-certified neurologist practicing in southern Louisiana. She cares for a variety of patients in all fields of neurology, including epilepsy, headache, dementia, movement disorders, multiple sclerosis, and stroke.

She received a bachelor's degree in international studies and history from the University of Miami and a master's in international relations from American University. She graduated from the Louisiana State University School of Medicine, where she also did her internship in internal medicine and her residency in neurology.

Prior to practicing medicine, she worked in international relations and owned a foreign language instruction and translation company. 

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Kaufman enjoys going on restaurant adventures, reading novels, making soup in her slow cooker, and hanging out with her dog. She lives in New York City with her husband and two kids.

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