Dementia: Symptoms, Causes, Diagnosis, Treatment, and Prevention
Neurological DisordersDementia

What Is Dementia?

What Is Dementia?
Everyday Health
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Updated on March 30, 2026
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Dementia is not a disease. Instead, it is a syndrome — a set of symptoms — that occurs when neurons (nerve cells) in the brain stop working, lose connections with other brain cells, and die.

Eventually, this leads to a loss of cognitive ability that is significant enough to disrupt a person’s daily life. The National Institute on Aging defines this cognitive decline as dementia.

Dementia ranges from mild to severe. In the final stages, people become completely incapable of caring for themselves and require around-the-clock help with the most basic aspects of daily living.

Up to half of all men and women ages 85 and older (sometimes called “the oldest old”) have some form of dementia, yet experts do not consider it a normal part of aging. Many people live into their nineties with their cognitive abilities intact.

Some people with dementia may be unable to control their emotions, or they may exhibit personality changes.

They may also grapple with hallucinations (seeing or experiencing things that don’t exist) or delusions (convictions not grounded in reality).

Dementia is different for everybody. Kalisha Bonds-Johnson, PhD, RN, of Emory University’s Nell Hodgson Woodruff School of Nursing in Atlanta, Georgia, explains how.

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If You Know One Person With Dementia…

Dementia is different for everybody. Kalisha Bonds-Johnson, PhD, RN, of Emory University’s Nell Hodgson Woodruff School of Nursing explains how.

Stages of Dementia

People with dementia will always see their symptoms worsen over time, but not every person with the same type of dementia will decline at the same rate or experience the same symptoms at the same stage. Certain symptoms may never appear, stages may overlap, and symptoms may appear then disappear. Every person with dementia has a unique set of symptoms.

Outlining the stages of dementia, however, can be useful for people considering their future caregiving needs, hoping to enlist in clinical trials, or otherwise planning ahead.

Understanding the earliest stages of dementia can also help people make sense of puzzling brain glitches. In fact, researchers now identify a condition called mild cognitive impairment as a precursor to dementia for some people. This condition involves lapses in memory, language, thinking, and judgment that are noticeable to the affected person but not severe enough to affect everyday functioning. It affects 12 to 18 percent of people ages 60 and over, according to the Alzheimer’s Association.

Each of the four most common types of dementia (Alzheimer’s, vascular dementia, Lewy body dementia, and frontotemporal disorders) has early symptoms that can help a doctor identify the type. Unlike the short-term memory loss of Alzheimer’s, for instance, vascular dementia may reveal itself as difficulty making plans or decisions.

In their advanced stages, though, symptoms of different dementia types all tend to become more like Alzheimer’s, including:

  • Short-term memory loss
  • Loss of awareness of surroundings
  • Difficulty communicating

Signs and Symptoms of Dementia

Dementia involves impairment of core cognitive functions that is severe enough to affect a person’s ability to do normal everyday tasks. These functions include:

  • Memory
  • Language skills
  • Visual perception
  • The ability to focus and pay attention
  • The ability to reason and solve problems
While short-term memory loss can be an early sign of dementia, particularly Alzheimer’s, different types of dementia may have different symptoms.

When vascular dementia develops after multiple small strokes, for instance, people may have difficulty with judgment and planning or may become increasingly unable to focus.

With Lewy body dementia, people may experience visual hallucinations — imagining they see things that aren’t there — or they may alternate between periods of alertness and confusion (day to day, or even hour to hour). Movement problems are also common, such as muscle rigidity, shaking or tremor, and loss of coordination.

Some people with frontotemporal dementia exhibit extreme changes in behavior and personality. They may, for instance, begin making wildly inappropriate comments in social situations or show a startling lack of inhibition.

 In a form of frontotemporal dementia called primary progressive aphasia, people have difficulty expressing their thoughts or finding words.

An accurate diagnosis is the first step toward getting the right kind of treatment and support for your dementia.

Causes and Risk Factors of Dementia

Dementia occurs when nerve cells in the brain stop working, lose connections with other brain cells, and die. Researchers are still working to understand why this happens and are investigating the role that genetics, lifestyle, and environment all play as dementia risk factors.

Genes, which pass from parents to their offspring, are believed to play a role in almost every type of dementia. Yet, except in rare cases of a single-gene mutation, people don’t inherit dementia directly. Instead, their odds depend on some combination of genetic, environmental, and lifestyle factors.

However, genetics seems to have a more significant impact on certain kinds of dementia. About 10 to 15 percent of people with a form of dementia called frontotemporal disorders (also known as frontotemporal dementia) have a strong family history.

Scientists have observed an association between certain kinds of dementia and high levels of proteins in the brain, as with the protein beta-amyloid (plaques) in Alzheimer’s disease.

Lewy body dementia, the third most common form of dementia, is associated with abnormal deposits of a protein called alpha-synuclein. In a healthy brain, alpha-synuclein helps neurons communicate. But when alpha-synuclein begins to clump inside neurons, forming so-called Lewy bodies, brain function is impaired, impacting thinking, movement, behavior, and mood.

Risk factors for Lewy body dementia include a family history of the condition, older age, having Parkinson’s disease, and having a condition called REM (rapid eye movement) sleep behavior disorder, which causes people to physically act out vivid, sometimes violent, dreams in their sleep.

Vascular dementia has been linked to damaged arteries that block the flow of blood to areas of the brain, depriving brain cells of the oxygen and nutrients they need to function. Sometimes, small blockages in blood vessels don’t cause any immediate symptoms but can lead to dementia as more and more of the brain becomes damaged.

Risk factors include:

  • A buildup of fatty deposits in the arteries, known as atherosclerosis
  • High cholesterol
  • High blood pressure
  • Diabetes
  • Smoking
At this point, the main risk factor scientists have identified for frontotemporal disorders is family history. But researchers have found genetic similarities between the underlying brain condition, frontotemporal degeneration, and amyotrophic lateral sclerosis (ALS, also known as Lou Gehrig’s disease). Exploring those similarities may help scientists better understand and treat both illnesses.

How Is Dementia Diagnosed?

In general terms, diagnosing dementia is typically much easier than identifying the underlying brain disorder. Symptoms of different types of dementia may overlap, and people can have more than one type of dementia at the same time.

However, the right diagnosis is critical to getting the best treatment. Typically, this process starts with your primary care doctor, although specialists such as a neurologist, neuropsychologist, or geriatrician may also play a role.

The first task is ruling out treatable or reversible conditions with symptoms that can mimic dementia, such as depression or a thyroid problem. Your doctor will take a detailed medical history, conduct a physical exam and a neuropsychological assessment, and order lab tests.

Neuropsychological assessments help doctors identify cognitive patterns that may indicate a particular brain disorder. These tests assess cognitive skills such as memory, problem-solving, language abilities, and focus.

Your doctor may also use imaging scans like MRI, CT, or PET to look at your brain.

Treatment and Medication Options for Dementia

There is currently no cure for any of the progressive brain diseases that cause dementia. But there are several potential ways to treat dementia, depending on your underlying condition.

Medication Options

Disease-Modifying Monoclonal Antibody Therapies

Some newer drugs may slow down the process of cognitive decline in the early stages of Alzheimer’s disease. These drugs — lecanemab (Leqembi) and donanemab (Kisunla) — work by preventing plaques from clumping in the brain.

But no evidence suggests that these drugs restore cognitive function that has already been lost, or prevent Alzheimer’s from progressing further. They have only been studied in people with mild cognitive impairment or early-stage Alzheimer’s, not in people with more advanced Alzheimer’s or with other forms of dementia.

Examples of disease-modifying monoclonal antibody therapies include:

  • lecanemab (Leqembi)
  • donanemab (Kisunla)
This group of drugs remains controversial, with many experts raising concerns about their effectiveness, safety, and cost.

Other medications may reduce or stabilize some of the symptoms of dementia, at least for a while. Many have been approved by the U.S. Food and Drug Administration to treat Alzheimer’s disease, with clinical evidence that they can also help people with other forms of dementia.

Cholinesterase Inhibitors

People with Lewy body dementia, for instance, may take a group of drugs approved for Alzheimer’s called cholinesterase inhibitors. These medications may help with memory loss and confusion, as well as behavioral problems and hallucinations.

Cholinesterase inhibitors include:

  • donepezil (Aricept)
  • rivastigmine (Exelon)
  • galantamine (Razadyne)

Blood Pressure and Cholesterol Medication

Treatment for vascular dementia typically focuses on addressing underlying issues with your heart and blood vessels, potentially slowing the rate of cognitive decline. Depending on your needs, a physician may prescribe drugs to reduce your blood pressure, lower your cholesterol, prevent blood clots, or control your blood sugar if you have diabetes.

Antidepressants

Frontotemporal disorders are particularly difficult to treat with drugs because people can have adverse and even dangerous reactions to some medications. Certain antidepressants, though, may help curb social disinhibition or impulsivity.

Behavioral and Occupational Therapy

Drug treatments aren’t the only way to address dementia. You may benefit from individual sessions with a mental health counselor to deal with feelings of stress or grief. An occupational therapist may also help make your home simpler and safer. Support group meetings with other people coping with dementia may also be an option.

Hundreds of clinical trials in the United States are looking at dementia. Investigators working with people online and at centers around the country are studying both pharmaceutical and nonpharmaceutical interventions.

Participants in these clinical trials, including people with dementia and those at risk, can access potential treatments before they are in widespread use while also helping find a cure for future generations.

Lifestyle Changes for and Prevention of Dementia

Lifestyle Changes for Dementia

Reduce Stress

People with dementia may improve their quality of life by focusing on their overall well-being and taking steps to reduce stress, simplify tasks, and reduce clutter at home.

Eat Well and Exercise

You can enhance your physical health by staying active, eating well, and engaging in activities that involve social interaction or stimulate your brain.

Stay Social and Find Meaning

To boost psychological health, relationships are key. Having close friends who can provide emotional support can lift your feelings of well-being and self-worth.

People with dementia can also nourish their spiritual health by taking part in meaningful activities, whether that means outings with family and friends or quiet, meditative moments alone pursuing a hobby like yoga.

Caregivers can help improve the quality of life for people with dementia by knowing the best ways to communicate and having strategies to overcome cognitive or behavioral challenges. For instance, presenting complex tasks step by step can increase the likelihood of success and foster confidence.

Keep a Routine

Since many people with dementia tend to have worse symptoms in the evening, a calming routine before bed can help — meaning no noise from family members’ conversations or television, and no chores like meal cleanup. Having plenty of night lights can also help with disorientation.

Prevention of Dementia

While your genetic makeup is known to play a role in dementia risk, in most cases it’s just one piece of the puzzle. Researchers are actively investigating lifestyle and environmental factors that may increase or decrease your risk of developing dementia.

Keep Your Heart Healthy

The best way to protect your brain from vascular dementia may be to protect your heart. This means not smoking, getting enough physical activity, and keeping your blood pressure and cholesterol in check.

Stay Social

Scientists are actively investigating other lifestyle factors that can affect dementia risk. Ongoing research on social engagement is analyzing the impact of factors like marital status and emotional connectedness. Some evidence supports an association between higher levels of social engagement and a lower dementia risk.

Get Better Sleep

Another area of study is the link between sleep and dementia. One study found that compared with older adults who reported typically getting six to eight hours of sleep, those who got less than five hours of sleep were about twice as likely to develop dementia after five years.

How Long Does Dementia Last?

Dementia is an ongoing condition that becomes more severe over time. How quickly your dementia progresses will depend on many factors, including the type of dementia you have, and it varies from person to person.

For Alzheimer’s disease, the average length of time from diagnosis to death is four to eight years, but some people live as long as 20 years, according to the Alzheimer’s Association. A diagnosis at an older age typically means a shorter time before death.

People with vascular dementia typically live for about five years and are more likely to die from a stroke or heart attack than from their dementia. Those with Lewy body dementia typically live for about six years.

For individuals with frontotemporal dementia, the typical length of time from diagnosis to death is six to eight years. But those with motor neuron disease linked to this form of dementia typically live for only two to three years after diagnosis.

Complications of Dementia

Dementia is a progressive neurodegenerative syndrome that affects cognitive, behavioral, and functional abilities. As the disease advances, individuals frequently develop a range of medical and functional complications that significantly contribute to morbidity, hospitalizations, and mortality. Many of these complications arise from declining neurological function, impaired mobility, difficulty swallowing, and reduced ability to perform activities of daily living.

Aspiration Pneumonia and Respiratory Infections

One of the most serious complications of dementia is aspiration pneumonia, which occurs when food, saliva, or stomach contents enter the lungs. Progressive neurological decline often leads to dysphagia (swallowing difficulty), increasing the likelihood of aspiration.

Swallowing difficulties can also contribute to dehydration, malnutrition, and respiratory infections. In advanced dementia, aspiration pneumonia is a leading cause of hospitalization and death, highlighting the importance of monitoring swallowing function and respiratory health.

Malnutrition and Weight Loss

Malnutrition is highly prevalent among people living with dementia. Cognitive impairment can reduce appetite, disrupt eating behaviors, and impair the ability to recognize hunger or to use utensils properly. In addition, difficulty swallowing and behavioral symptoms such as agitation may further interfere with adequate nutritional intake. Studies have shown that poor nutritional status in dementia is associated with worse functional decline, increased morbidity, and higher mortality risk.

Falls and Functional Decline

As dementia progresses, individuals often experience impaired balance, reduced coordination, and decreased judgment, which substantially increases the risk of falls. Falls can lead to fractures, head injuries, and loss of independence. Functional decline in activities of daily living, including bathing, dressing, and mobility, further contributes to physical frailty and increased healthcare utilization.

Delirium and Neuropsychiatric Complications

People with dementia are particularly vulnerable to delirium, an acute state of confusion often triggered by infections, medications, or hospitalization. Delirium can accelerate cognitive decline, prolong hospital stays, and increase the risk of long-term functional deterioration.

 Neuropsychiatric symptoms such as agitation, hallucinations, and depression are also common complications that significantly impact quality of life and caregiver burden.

Pressure Injuries and Immobility

Advanced dementia frequently leads to decreased mobility and prolonged bed rest. Reduced movement increases the risk of pressure injuries or bedsores, infections, blood clots, and muscle wasting.

 These complications can worsen overall health status and increase the need for long-term care or institutionalization.

Increased Mortality

Complications such as pneumonia, malnutrition, and frailty contribute substantially to the elevated mortality observed in individuals with dementia. Research indicates that dementia independently increases mortality risk beyond the effects of other chronic conditions, emphasizing the importance of comprehensive medical management and supportive care.

FAQ

1What’s the difference between dementia and Alzheimer’s disease?
Dementia is cognitive impairment, from any cause, that significantly affects your daily life. Alzheimer’s disease is the most common type of dementia, and it involves a specific pattern of brain changes involving abnormal protein clumps (plaques) and fibers (tangles).
The leading causes of dementia are Alzheimer’s disease, vascular dementia, Lewy body dementia, and frontotemporal dementia. While each of these dementia types has different risk factors, overall, you’re more likely to develop dementia the older you get after age 65.
Depending on the type, dementia symptoms can include increased forgetfulness, difficulty following conversations, difficulty with judgment and planning, visual hallucinations, movement problems, reduced inhibitions, drastic behavioral changes, and inappropriate behaviors.
Certain drugs may slow the progression of Alzheimer’s disease, while other drugs are used to treat symptoms in multiple types of dementia. But dementia can’t be cured, and it gets worse over time.
There’s no sure way to prevent dementia, but you may be able to reduce your dementia risk by staying physically active, not smoking, and keeping your blood pressure and cholesterol under control.
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.
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