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Dementia: Signs, types, causes, treatment

Reviewed by Cathy Leeson, SLP

Tree concept to illustrate dementia.

Dementia affects 55 million people1 worldwide, according to the World Health Organization. Many people with dementia are elderly, but it may have an earlier onset. 

What Is Dementia?

Dementia is a group of neurologic symptoms characterized by a steady decline in cognitive functioning. It is often associated with forgetfulness, but dementia involves more than memory issues. People with dementia experience a cognitive decline that progressively interferes with many areas of their daily lives. 

What Is the Difference Between Dementia and Alzheimer’s?

The term “dementia” describes the decline in cognitive function that interferes with everyday life. Many different neurological diseases may cause dementia. Alzheimer’s disease is just one of them, but it is the most common. Alzheimer’s causes up to 80%2 of all dementia cases. 

Signs of Dementia

Although different diseases may cause dementia, most of the signs and symptoms are similar. Many people experience increasing severity of:

  • Memory loss
  • Mood changes
  • Difficulty communicating
  • Getting lost in familiar places
  • Trouble with planning and organization
  • Difficulty problem-solving
  • Experiencing hallucinations or delusions
  • Struggling to manage money
  • Repeating oneself 
  • Poor impulse control
  • Loss of balance
  • Agitation

Symptoms start out mild and get dramatically worse over time. They may begin with losing keys or forgetting things with increasing frequency. Eventually, the cognitive decline becomes so severe that the person with dementia forgets who their loved ones are and doesn’t recognize their surroundings.  

Types of Dementia

Alzheimer’s disease causes the majority of dementia cases. However, there are several other neurologic diseases that can also cause dementia. 


Alzheimer’s disease causes neurons to die, and it shrinks your brain as it progresses. It also causes clumps called amyloid plaques and tangles of fibers to develop in your brain over time. These changes take place over many years, long before the first symptoms become apparent. 

Vascular Dementia

Unlike Alzheimer’s, the cause of vascular dementia is readily apparent. A vascular event in the brain can deprive it of blood. This blood deprivation may kill brain cells, resulting in irreversible brain damage. Depending on where this damage occurs, one might experience a decline in cognitive function. 

Vascular events that may cause dementia include stroke, a brain bleed, or damage to blood vessels from other conditions. Diabetes, high blood pressure, atherosclerosis, and regular damage as a result of aging can all contribute to vascular dementia. 

Lewy Body Dementia

People with Lewy body dementia develop Lewy bodies throughout their brain. Lewy bodies are an accumulation of the protein alpha-synuclein in the brain. These Lewy bodies alter the chemicals in the brain, which results in dementia symptoms. It is the second most common type of dementia, affecting more than a million3 Americans. 

Frontotemporal Dementia

Frontotemporal dementia results from the loss of brain cells in the frontal and temporal lobes of your brain. Several different diseases can cause frontotemporal dementia, and it may present with different symptoms. 

The frontal variant primarily causes personality changes and uncharacteristic behavior. Primary progressive aphasia is the other type of frontotemporal dementia. This type of dementia causes difficulty with language. Primary progressive aphasia may cause one to lose the ability to speak or make it difficult to understand or express language. 

Mixed Dementia

People with mixed dementia have changes in their brain that indicate more than one kind of dementia. A definitive diagnosis for mixed dementia isn’t usually reached until a person has died. An autopsy allows doctors to see what changes occurred in their brain, and these changes are different for each type of dementia. 

Dementia-like Disorders

There are several disorders with symptoms that mimic dementia. A doctor can evaluate to diagnose or rule out these conditions:

  • Traumatic brain injury (TBI)
  • Parkinson’s disease
  • Huntington’s disease
  • Creutzfeldt-Jakob disease

What Causes Dementia?

Doctors don’t yet know what causes Alzheimer’s disease, but they have identified several risk factors, including family history and age. They also suspect that environmental factors and lifestyle choices may influence the onset of Alzheimer’s.

Is Dementia Hereditary?

Some links to genetics have been found with dementia. Certain types of dementia are more likely to be hereditary. For example, early-onset Alzheimer’s is more likely to be passed on than later developing types. 

Vascular dementia is not passed down directly, but genetics can play a role in risk factors, such as hypertension, diabetes and heart disease. Frontotemporal dementia is more likely to be genetically passed. Approximately 40% of people diagnosed with this type have a close family member with some type of dementia. 

Dementia Risk Factors

The risk factors for dementia are broad. Not everyone who has some of these risks will get dementia, however.  

  • Older age: As you age, your risk for dementia increases.
  • Family history: People with family members who have or have had dementia are at a greater risk of developing dementia themselves.
  • Ethnicity: People of color tend to have a higher risk for dementia.
  • Heart health: People who have cardiovascular health problems have a greater risk for vascular dementia in particular.
  • Nutritional deficiencies: There is some evidence that not getting enough of certain vitamins or not following a healthy diet may increase a person’s risk for dementia.

4 Stages of Dementia

There are several stages in the development of dementia. The symptoms of each stage occur as damage to your brain progresses. 

1. No Impairment

The first stage of dementia doesn’t come with any obvious symptoms. This is because people with dementia have brain changes long before they exhibit any symptoms. Diagnostic tests may reveal a dementia diagnosis in this stage. 

2. Early-stage Dementia

A person with early-stage dementia is still independent. Their loved ones may notice mild changes in behavior, like losing things or difficulty with organization, but they can still take care of themselves safely. 

3. Mid-stage Dementia

People who advance to mid-stage dementia will experience more symptoms that have a significant impact on their daily life. At this stage, a person with dementia may have changes in sleep patterns  and experience confusion. They may become unpredictable, displaying uncharacteristic behavior. Once they progress to this stage of dementia, they will need a higher level of care to prevent injuries or getting lost. 

4. Late-stage Dementia

In this final stage, a person with dementia will require round-the-clock care. They will have difficulty communicating and remembering people and things. In addition to declining cognitive function, people in late-stage dementia also lose control of their movements and are susceptible to infections. 

How to Prevent Dementia

If you are at higher risk for developing dementia, there are several things you can do to reduce your risk:

  • Eat a healthy diet
  • Exercise regularly
  • Don’t smoke
  • Get appropriate amounts of sleep
  • Keep your mind active
  • Refrain from drinking too much alcohol

How Is Dementia Diagnosed?

Reaching a diagnosis for dementia involves several tests. Doctors use brain scans, blood tests, and other diagnostic procedures to confirm the diagnosis. 

Testing Methods

There are several tests that doctors might order if they suspect dementia. These include: 

  • Neurologic exams
  • Brain scans
  • Psychiatric evaluation
  • Blood tests
  • Brain donation

Since a diagnosis for a specific type of dementia may be difficult to reach without examining the brain during an autopsy, doctors often suggest that patients donate their brains to science after passing. This allows doctors to identify the specific cause of the illness and contribute to research. 

What Is the FAST Scale for Dementia?

The Reisberg Functional Assessment Staging (FAST) Scale is a tool used to measure the severity of Alzheimer’s on a functional level. Instead of measuring cognitive decline, it measures how well a person with Alzheimer’s is functioning in everyday life. There are seven stages that are identified using 16 criteria as follows:

  • Stage 1: Completely independent without any symptoms or disruption to daily living. 
  • Stage 2: Forgetting where things are and starting to have difficulty at work. 
  • Stage 3: Co-workers are noticing difficulty, new environments are becoming uncomfortable or disorienting.. 
  • Stage 4: Complex tasks like managing finances become more difficult. 
  • Stage 5: Needing assistance with choosing appropriate clothing. 
  • Stage 6: Needing help putting on clothes, bathing, and using the toilet. 
  • Stage 7: Losing the ability to speak, develop limitations in mobility, and experience altered consciousness. 

Documenting your levels of independence using the FAST Scale can help one access care and services through programs like Medicare and Medicaid. 

How to Treat Dementia

People with dementia have limited treatment options. There isn’t a cure for dementia, but medication and therapy can manage symptoms and increase quality of life. 


Most people with dementia take medication to help manage the symptoms and delay disease progression, such as acetylcholine inhibitors and namenda.


People with dementia can benefit from therapeutic interventions beyond medications. These approaches may help to stimulate memory, develop coping strategies and organizational systems, modify the environment, and help with mood regulation:

  • Occupational therapy
  • Speech-language therapy
  • Art therapy
  • Music therapy

Lifestyle Changes

Lifestyle changes may also help slow the progression of dementia. Following the MIND diet, which is a cross between the Mediterranean diet and the DASH diet, encourages brain health and lowers the incidence of dementia.  Social activities, brain challenges such as puzzles or word games, and participating in hobbies might also help delay more severe symptoms. 

Dementia Treatment

If you have been diagnosed with dementia, it is important to engage with a therapist that will help you navigate the progression of the disease. This will help you recognize and develop coping skills for any symptoms of depression, anxiety or despair you may experience following your diagnosis. Relatives and caregivers of people with dementia may also want to consider seeking help from a therapist for help with grief and stress.

Finding a therapist is convenient and easy when you use our therapist directory. Simply search for a therapist specializing in your needs, and you’ll be able to find one in your area. 

About the author

The editorial team at works with the world’s leading clinical experts to bring you accessible, insightful information about mental health topics and trends.