Dementia is a neurodegenerative disease that has several different forms, symptoms, and causes. There’s currently no cure, but researchers are looking into effective treatments and ways to prevent it.

Dementia is a decline in cognitive function. To be considered dementia, mental impairment must affect at least two brain functions. Dementia may affect:

  • memory
  • thinking
  • language
  • judgment
  • behavior

Dementia may be caused by a variety of illnesses or injuries. Mental impairment may range from mild to severe. It may also cause personality changes.

Some types of dementia are progressive. This means they get worse over time. Some types are treatable or even reversible. Some experts restrict the term “dementia” to irreversible mental deterioration.

In its early stages, dementia can cause symptoms, such as:

  • Not coping well with change. Someone may have a hard time accepting changes in schedules or environment.
  • Subtle changes in short-term memory making. Someone can remember the events of 15 years ago like it was yesterday, but they can’t remember what they had for lunch.
  • Reaching for the right words. Word recollection or association may be more difficult.
  • Being repetitive. Someone may ask the same question, complete the same task, or tell the same story multiple times.
  • Confused sense of direction. Places someone once knew well may now feel foreign. They may also struggle with driving routes they’ve taken for years because it no longer looks familiar.
  • Struggling to follow storylines. Someone may find following a person’s story or description difficult.
  • Changes in mood. Depression, frustration, and anger are not uncommon for people with dementia.
  • Loss of interest. Apathy may occur in people with dementia. This includes losing interest in hobbies or activities that they once enjoyed.
  • Confusion. People, places, and events may no longer feel familiar. Someone might not remember people who know them.
  • Difficulty completing everyday tasks. A person in the early stages of dementia may have trouble recalling how to do tasks they’ve done for many years.

Dementia has many causes. In general, it results from the degeneration of neurons (brain cells) or disturbances in other body systems that affect how neurons function.

Several conditions can cause dementia, including diseases of the brain. The most common causes are Alzheimer’s disease and vascular dementia.

Some of the more common causes of dementia include:

Neurodegenerative diseases

“Neurodegenerative” means that neurons gradually stop functioning or function inappropriately and eventually die.

This affects the neuron-to-neuron connections, called synapses, which arehow messages are passed along in your brain. This disconnect can result in a range of dysfunction.

Another cause is frontotemporal lobar degeneration. This is a blanket term for a range of conditions that cause damage to the frontal and temporal lobes of the brain. They include:

Other causes of dementia

Dementia has other causes, including:

Some of these types of dementia may be reversible. These treatable causes of dementia may reverse symptoms if they’re caught early enough. This is one of the many reasons why it’s important to contact your doctor and get a medical workup as soon as symptoms develop.

Most cases of dementia are a symptom of a specific disease. Different diseases cause different types of dementia. The most common types of dementia include:

  • Alzheimer’s disease. The most common type of dementia, Alzheimer’s disease makes up 60 to 80 percent of dementia cases, according to the Alzheimer’s Association.
  • Vascular dementia. This type of dementia is caused by reduced blood flow in the brain. It may be the result of plaque buildup in arteries that feed blood to the brain or a stroke.
  • Lewy body dementia. With Lewy body dementia, protein deposits in nerve cells prevent the brain from sending chemical signals. This results in lost messages, delayed reactions, and memory loss.
  • Parkinson’s disease. Individuals with advanced Parkinson’s disease may develop dementia. Symptoms of this particular type of dementia include problems with reasoning and judgment, as well as increased irritability, paranoia, and depression.
  • Frontotemporal dementia. Several types of dementia fall into this category. They’re each affected by changes in the front and side parts of the brain. Symptoms include difficulty with language and behavior, as well as loss of inhibitions.

Other types of dementia exist. However, they’re less common. In fact, one type of dementia, Creutzfeldt-Jakob disease, occurs in only 1 in 1 million people.

In most cases, dementia is progressive, getting worse over time. That said, dementia progresses differently in everyone. However, most people experience symptoms of the following stages of dementia.

Mild cognitive impairment

Older adults may develop mild cognitive impairment (MCI) but may never progress to dementia or any other mental impairment. People with MCI commonly experience forgetfulness, trouble recalling words, and short-term memory problems.

Mild dementia

At this stage, people with mild dementia may be able to function independently. Symptoms include:

  • short-term memory lapses
  • personality changes, including anger or depression
  • misplacing things or forgetfulness
  • difficulty with complex tasks or problem solving
  • difficulty expressing emotions or ideas

Moderate dementia

At this stage of dementia, people affected may need assistance from a loved one or care professional. That’s because dementia may now interfere with daily tasks and activities. Symptoms include:

  • poor judgment
  • increasing confusion and frustration
  • memory loss that reaches further into the past
  • needing help with tasks like dressing and bathing
  • significant personality changes

Severe dementia

At this late stage of dementia, the mental and physical symptoms of the condition continue to worsen. Symptoms include:

  • inability to maintain bodily functions, including walking and eventually swallowing and controlling the bladder
  • inability to communicate
  • requiring full-time assistance
  • increased risk of infections

People with dementia will progress through the stages of dementia at different rates.

No single test can confirm a dementia diagnosis. Instead, a doctor will use a series of tests and exams. These include:

  • a thorough medical history
  • a careful physical exam
  • laboratory tests, including blood tests
  • a review of symptoms, including changes in memory, behavior, and brain function
  • a family history

Doctors can determine if you or a loved one is experiencing symptoms of dementia with a high degree of certainty. However, they may not be able to determine the exact type of dementia. In many cases, symptoms of dementia types overlap. That makes distinguishing between types difficult.

Some doctors will diagnose dementia without specifying the type. In that case, you may wish to visit a doctor who specializes in diagnosing and treating dementia. These doctors are called neurologists. Some geriatricians also specialize in this type of diagnosis.

Two primary treatments are used to alleviate symptoms of dementia: medications and non-drug therapies. Not all medications are approved for each type of dementia, and no treatment is a cure.

Medications for dementia

Two main types of medication are used to treat symptoms of Alzheimer’s disease and other dementia-causing conditions:

  • Cholinesterase inhibitors. These drugs increase a chemical called acetylcholine. This chemical may help form memories and improve judgment. It may also delay worsening symptoms of Alzheimer’s disease.
  • Memantine. This drug is used to delay the onset of cognitive and behavioral symptoms in people with moderate or severe Alzheimer’s disease. Memantine may let people with Alzheimer’s disease maintain their usual mental functions for a longer period of time.

These two drugs may also be prescribed together. Side effects can occur. Other medications may be prescribed to treat related symptoms, such as impaired sleep, mood changes, and more.

Aducanumab (Aduhelm)

Aducanumab is another medication approved to treat Alzheimer’s and may slow the progression of the disease, though research is ongoing. Aducanumab is an anti-amyloid antibody therapy delivered intravenously. It targets a specific protein fragment that can disrupt communication between nerve cells in the brain.

Non-drug therapies

These therapies may help reduce symptoms of dementia and alleviate some of the manageable complications of the condition. Common non-drug treatments for dementia include:

  • Modifying your environment. Clutter, noise, and overstimulation may reduce focus.
  • Modifying common tasks. You can work with a therapist or other healthcare professional to break down everyday activities, such as showering or grooming, into manageable tasks.
  • Occupational therapy. Occupational therapists are specialized healthcare professionals who can help you learn to be safer and more secure with tasks including walking, cooking, and driving.

For decades, doctors and researchers believed dementia could not be prevented or cured. However, new research suggests that may not be the case.

A 2017 review found that more than one-third of dementia cases may be the result of lifestyle factors. Specifically, the researchers identified nine risk factors that may increase a person’s chance of developing dementia. They include:

The researchers believe that targeting these risk factors with treatment or intervention could delay or possibly prevent some cases of dementia.

A 2019 retrospective study looked at nearly 200,000 participants of European ancestry. The study suggested that lifestyle factors such as smoking status, physical activity, diet, and alcohol consumption could potentially contribute to the risk of dementia.

These findings suggest that working with your doctor to maintain a healthy and active lifestyle could help prevent or delay the onset of dementia.

Individuals living with dementia can and do live for years after their diagnosis. It may seem that dementia is not a fatal disease because of this. However, late-stage dementia is considered terminal.

It’s difficult for doctors to predict life expectancies in people with dementia. Likewise, factors that influence life expectancy may have a different impact on the length of life in each person.

In one 2015 study, women diagnosed with Alzheimer’s disease lived an average of 5.7 years after diagnosis. Men lived 4.2 years. Life expectancies, the study found, may be shorter for individuals with other types of dementia.

Certain risk factors increase the likelihood of death in people with dementia. These factors include:

  • increased age
  • being born male
  • decreased capabilities and functionality
  • additional medical conditions, diseases, or diagnoses, such as diabetes or cancer

However, it’s important to remember that dementia doesn’t follow a specific timeline. You or your loved one may progress through the stages of dementia slowly, or the progression may be rapid and unpredictable. This will affect life expectancy.

Dementia and Alzheimer’s disease are not the same. Dementia is an umbrella term used to describe a collection of symptoms related to memory, language, and decision making.

Alzheimer’s disease is the most common type of dementia. It causes difficulty with things like:

  • short-term memory
  • depression
  • disorientation
  • behavioral changes

Dementia causes symptoms such as:

  • forgetfulness or memory impairment
  • loss of sense of direction
  • confusion
  • difficulty with personal care

The exact constellation of symptoms will depend on the type of dementia you have.

Alzheimer’s disease can also cause these symptoms, but other symptoms of Alzheimer’s may include depression, impaired judgment, and difficulty speaking.

Likewise, treatments for dementia depend on the type you have. However, Alzheimer’s disease treatments often overlap with other nonpharmacological dementia treatments.

In the case of some types of dementia, treating the underlying cause may be helpful in reducing or stopping the memory and behavior problems. However, that is not the case with Alzheimer’s disease.

Comparing the two may help you tell the difference between symptoms you or a loved one may be experiencing.

Alcohol use may be the most preventable risk factor for dementia. A 2018 study found that the majority of early onset dementia cases were related to alcohol use.

The study found that nearly one-third of early onset dementia cases were directly linked to alcohol. Plus, 18 percent of people in the study had been diagnosed with an alcohol use disorder.

Alcohol use disorders, the researchers discovered, increase a person’s risk of dementia threefold.

Not all drinking is dangerous to your memories and mental health. Moderate levels of drinking may even be beneficial to your heart’s health. This includes no more than one glass per day for women and two glasses per day for men.

It’s absolutely natural to forget things once in a while. Memory loss by itself does not mean you have dementia. There is a difference between occasional forgetfulness and forgetfulness that is cause for serious concern.

Potential red flags for dementia include:

  • forgetting who someone is
  • forgetting how to do common tasks, such as how to use the telephone or find your way home
  • inability to comprehend or retain information that has been clearly provided

Get medical attention if you experience any of the above.

Getting lost in familiar settings is often one of the first signs of dementia. For example, you might have trouble driving to the supermarket.

According to the World Health Organization (WHO), approximately 55 million people have dementia worldwide, with around 10 million new cases reported each year.

The number of people receiving dementia diagnoses or living with dementia is increasing. This increase is due partly to increasing life expectancy.

By 2030, the size of the population 65 years of age and older in the United States is expected to almost double from 37 million people in 2006 to an estimated 74 million by 2030, according to the Federal Interagency Forum on Aging-Related Statistics.

The rates of dementia will likely increase with this larger population of people older than 65.

Scientists all over the world are working to gain a better understanding of the many different aspects of dementia. This might help to develop preventive measures, improved early detection diagnostic tools, better and longer-lasting treatments, and even cures.

For example, 2018 research on mice suggests a common asthma drug called zileuton might slow, stop, and potentially reverse the development of proteins in the brain. These proteins are common in people with Alzheimer’s disease.

Another 2021 review suggests deep brain stimulation could be an effective way to limit symptoms of Alzheimer’s in older adults. This method has been used to treat symptoms of Parkinson’s disease, such as tremors, for decades.

Even simple blood tests have now been developed that can detect Alzheimer’s, according to a 2021 study. As well, researchers are looking at the possibility of slowing the progression of Alzheimer’s.

Scientists are investigating a variety of factors they think might influence the development of dementia, including:

  • genetic factors
  • various neurotransmitters
  • inflammation
  • factors that influence programmed cell death in the brain
  • tau, a protein found in neurons of the central nervous system
  • oxidative stress, or chemical reactions that can damage proteins, DNA, and lipids inside cells

This research can help doctors and scientists better understand what causes dementia, and then discover how best to treat and possibly prevent the disorder.

According to a 2019 study, there is also increasing evidence that lifestyle factors may be effective in decreasing the risk of developing dementia. Such factors might include getting regular exercise and maintaining social connections.

Currently, the Centers for Disease Control and Prevention (CDC) says that Alzheimer’s disease is the seventh most common cause of death in the United States. That said, people with dementia will progress through the illness at varying speeds and experience different symptoms.

There is currently no cure for dementia, but plenty of research is still being done. Hopefully, one day, outlooks will improve.

If you’re experiencing memory issues or any other symptoms that point to dementia, talk with your doctor as soon as possible. Early diagnosis can help people with dementia and their families plan for the future.