Alzheimer’s disease and other types of dementia all affect memory, behavior, and communication. But dementia is a general term for these symptoms, while Alzheimer’s is the most common type of dementia that worsens with time.

Dementia and Alzheimer’s disease aren’t synonyms. Dementia is a general term that describes a gradual decline in memory, the performance of daily activities, and communication abilities.

Alzheimer’s disease is the most common type of dementia. Alzheimer’s disease gets worse with time and affects memory, language, and thought.

While younger people can develop dementia or Alzheimer’s disease, your risk increases as you age. Despite dementia or Alzheimer’s disease being most common in adults over 65, neither is considered an expected part of aging.

Symptoms of all types of dementia are similar, but distinguishing those of Alzheimer’s disease from others can help guide expectations and treatment.

Alzheimer’s disease is a type of dementia. It’s a progressive disease of the brain that slowly causes impairment in memory and cognitive function. The exact cause is unknown, and no cure is available.

Although younger people can and do get Alzheimer’s, the symptoms generally begin after age 65.

The effects of Alzheimer’s on the brain

In people with Alzheimer’s disease, brain cells die and connections between brain cells may break down. One of the hallmark symptoms is abnormal protein deposits in the brain called plaques and tangles.

Plaques are dense clusters of protein that can block communication between neurons. Tangles are proteins that twist together and lead to the death of healthy brain cells.

In advanced Alzheimer’s, the brain shows significant shrinkage. Changes in the brain may occur a decade or more before symptoms start.

It’s impossible to diagnose Alzheimer’s with complete accuracy while a person is alive. However, specialists can make the correct diagnosis up to 90% of the time based on symptoms and physical examination, along with ruling out other conditions.

A diagnosis can only be confirmed when the brain is examined under a microscope during an autopsy — and most people do not have an autopsy.

The World Health Organization (WHO) estimates that more than 55 million people around the world are living with dementia.

Dementia is a syndrome, and many diseases can cause it. A syndrome is a group of symptoms that often occur together and may have a shared underlying cause.

Dementia affects mental cognitive tasks such as memory and reasoning. It can occur due to a variety of conditions, the most common of which is Alzheimer’s disease.

People can have more than one type of dementia. This is known as mixed dementia.

People with mixed dementia have symptoms of two or more types of dementia. Many people are diagnosed with mixed dementia based on symptoms, physical examination, and diagnostic tests, but a diagnosis of mixed dementia can only be confirmed in an autopsy.

As dementia progresses, it can have a huge impact on the ability to function independently. It’s a major cause of disability for older adults and places an emotional and financial burden on families and caregivers.

Dementia is also the fifth leading cause of death globally, and cases are expected to triple over the next 30 years.

Causes of dementia

You’re more likely to develop dementia as you age. It occurs when certain brain cells are damaged. Many conditions can cause dementia, including degenerative diseases such as Alzheimer’s, Parkinson’s, and Huntington’s.

Each cause of dementia causes damage to a different set of brain cells.

Alzheimer’s disease is responsible for about 60–80% of all cases of dementia.

Other causes of dementia include:

According to the Centers for Disease Control and Prevention (CDC), older African Americans are twice as likely to develop dementia than non-Hispanic white people. Hispanic people are 1.5 times more likely to have dementia than non-Hispanic white people.

One reason for these statistics may be systemic inequities and barriers to healthcare for marginalized communities.

Symptoms of dementia

Early symptomsProgressive symptomsAdvanced symptoms
• occasional forgetfulness
• losing track of time
• losing your way in familiar settings
• frequent forgetfulness
• more confusion
• repetitive questioning
• poor hygiene
• poor decision making
• unable to care for yourself
• trouble with time
• difficulty remembering familiar people and places
• change in behavior
• depression
• aggression

It’s easy to overlook the early symptoms of dementia, which can be mild. Dementia often begins with simple episodes of forgetfulness. People with dementia have trouble keeping track of time and tend to lose their way in familiar settings.

As dementia progresses, forgetfulness and confusion grow. It becomes harder to recall names and faces. Personal care becomes a problem. Obvious signs of dementia include repetitious questioning, inadequate hygiene, and trouble with decision-making.

In the most advanced stage, people with dementia become unable to care for themselves. They will have more trouble keeping track of time and remembering people and places they are familiar with. Their behavior can continue to change and can turn into depression and aggression.

The symptoms of Alzheimer’s can overlap with symptoms of other types of dementia, but there can be some differences.

All types of dementia can cause:

  • a decline in the ability to think
  • memory impairment
  • communication impairment

The symptoms of Alzheimer’s include:

Some types of dementia will share some of these symptoms, but they include other symptoms that can help make a differential diagnosis.

Lewy body dementia (LBD), for example, has many of the same later symptoms as Alzheimer’s. But people with LBD are more likely to experience initial symptoms such as visual hallucinations, difficulties with balance, and sleep disturbances.

People with dementia due to Parkinson’s or Huntington’s disease are more likely to experience involuntary movement in the early stages of the disease.

Alzheimer’s disease is the most prevalent cause of dementia, but there are many other potential causes.

Vascular dementia

Vascular dementia is caused by a disease of the blood vessels in your brain and is often related to strokes or the buildup of plaque in your arteries. Symptoms can vary widely and may onset slowly or suddenly.

Dementia with Lewy bodies

Dementia with Lewy bodies is a progressive disease caused by protein deposits in your nerves that disrupt electrical signals. It may cause symptoms such as changes in thinking, confusion, and changes in movement patterns.

Parkinson’s disease dementia

Parkinson’s disease dementia is a decline in cognitive ability that often develops in some people with Parkinson’s a year or more after diagnosis. It’s estimated that about 50–80% of people with Parkinson’s eventually experience dementia, with an average onset of about 10 years after Parkinson’s disease diagnosis.

Frontotemporal dementia

Frontotemporal dementia is a group of conditions characterized by a decline of brain function in the part of your brain near your forehead or behind your ears. According to the Alzheimer’s Association, behavioral changes are often the first symptoms of frontotemporal dementia.

Posterior cortical atrophy

Posterior cortical atrophy is a progressive deterioration of the outer layer of your brain called the cortex, in the posterior part of your brain. Symptoms can vary, but often include problems with visual tasks such as reading or perceiving moving objects.

Creutzfeldt-Jakob disease

Creutzfeldt-Jakob disease is a rare infectious disease that affects about 350 people in the United States each year. It causes dementia that progresses rapidly and often starts with problems with muscle coordination, personality changes, and vision problems. About 70% of people die within a year.

Wernicke-Korsakoff syndrome

Wernicke-Korsakoff syndrome is a brain disorder caused by a lack of vitamin B1. The most common cause is chronic alcohol misuse. Symptoms may include double vision, confusion, drooping upper eyelids, and loss of muscle coordination.

Mixed dementia

Mixed dementia is when a person has more than one type of dementia. The most common combination is vascular dementia with Alzheimer’s disease. This combination affects as many as 22% of older adults.

Normal pressure hydrocephalus

Normal pressure hydrocephalus is a condition caused by a buildup of fluid in the ventricles of your brain. It can cause problems with cognition, movement, and bladder control. In most cases, the cause isn’t known.

But head injuries, infections, bleeding in your brain, and surgery can contribute to its development.

Huntington’s disease

Huntington’s disease is a rare condition that causes nerve cells in your brain to break down. A gene abnormality causes it. Early symptoms can include mood changes, psychosis, and poor coordination.

Treatment for dementia will depend on the exact cause and type of dementia, but many treatments for Alzheimer’s will overlap with treatments for other types of dementia.

Alzheimer’s treatment

No cure for Alzheimer’s is available, but options to help manage symptoms of the disease include:

  • medications for behavioral changes, such as antipsychotics
  • medications for memory loss, which include cholinesterase inhibitors donepezil (Aricept) and rivastigmine (Exelon), and memantine (Namenda)
  • alternative remedies that aim to boost brain function or overall health, such as coconut oil or fish oil
  • medications for sleep changes
  • medications for depression

Dementia treatment

In some cases, treating the condition that causes dementia may help. Conditions most likely to respond to treatment include dementia caused by:

In most cases, dementia isn’t reversible. However, many forms are treatable. The right medication can help manage dementia. Treatments for dementia will depend on the cause. For example, doctors often treat dementia caused by Parkinson’s disease, Alzheimer’s, and LBD with cholinesterase inhibitors.

Treatment for vascular dementia will focus on preventing further damage to the brain’s blood vessels and preventing stroke.

People with dementia can also benefit from supportive services from home health aides and caregivers. An assisted living facility or nursing home may be necessary as the disease progresses.

The outlook for people with dementia depends entirely on the direct cause. Treatments can make symptoms of dementia due to Parkinson’s manageable, but there isn’t currently a way to stop or even slow down related dementia.

Vascular dementia can be slowed down in some cases, but it still shortens a person’s lifespan. Some types of dementia are reversible, but most types are irreversible and will instead cause more impairment over time.

Alzheimer’s is a terminal illness, and no cure is currently available. The length of time each of the three stages lasts varies. People over 65 live an average of 4–8 years after receiving an Alzheimer’s diagnosis. Some people live as long as 20 years.

Alzheimer’s disease is a type of dementia. Its symptoms often overlap with those of other types of dementia.

If you’re concerned that you or a loved one may be experiencing symptoms of dementia or Alzheimer’s disease, talk with a healthcare professional. Based on symptoms, they can help distinguish between Alzheimer’s disease and other types of dementia.