Types of Dementia: What You Should Know

Medically Reviewed by Jabeen Begum, MD on May 16, 2024
9 min read

If you or someone you love gets diagnosed with dementia, it means you or they have a brain condition that causes issues with thinking, behavior, and memory. Dementia symptoms are known to get worse over time, but treatments may help slow that decline. Researchers continue to make progress toward understanding what causes dementia and how to help people who live with it.

There are many different types of dementia. You or your loved one's treatments will depend on the type you or they have.

How many types of dementia are there?

Dementia itself isn't a disease. It's an umbrella term used to describe symptoms that can be caused by many brain conditions.

All types of dementia fall into one of three groups:

Primary dementia. This means dementia is your main condition. 

Secondary dementia. If you have this type, doctors believe your dementia is caused by another health condition, like a stroke.

Reversible dementia. It's also possible to have short-term dementia-like symptoms due to a health issue, such as a lack of vitamins. Once the cause is treated, your symptoms can improve.



The most well-known types of dementia include:

Alzheimer's disease

This is what you might think of when you hear "dementia." It's the most common type. Around the world, as many as 70% of people with dementia have Alzheimer's. In the U.S. alone, about 6.5 million Americans who are 65 or older have been diagnosed.

Experts don't yet fully understand what causes Alzheimer's. It's probably due to a mix of natural aging, your genes, things in your environment, and things about your lifestyle, like what you eat and how much you sleep. The brain changes that Alzheimer's causes can actually be seen in brain imaging scans. Experts describe them as "plaques and tangles."

If you or someone you know has Alzheimer's, you could notice symptoms like memory loss and trouble planning and doing everyday tasks.

These might be mild at first but get more severe over time. Typical Alzheimer's signs include:

  • Repeating yourself
  • Getting turned around or lost in familiar places
  • Forgetting past conversations or scheduled events
  • Struggling to find the "right" words
  • Finding it hard to do more than one thing at once or follow multiple steps
  • Making poor judgments or reacting slowly
  • Changes in mood and personality

Vascular dementia

The second most common type of dementia happens when blood flow to your brain gets blocked. That can happen for a number of reasons, including heart disease, a stroke, a blood clot, or because of a major surgery. You're at higher risk of vascular dementia if you live with high blood pressure, high cholesterol, or diabetes.

The symptoms you have will depend on which part of your brain had decreased blood flow.

While Alzheimer's usually begins with memory problems, vascular dementia can start with trouble planning, organizing, and making decisions.

The signs of vascular dementia can also include:

  • Stroke-like symptoms, like finding it hard to speak 
  • Getting easily confused or upset, especially at night
  • Changes in your usual personality and mood
  • A change in how you walk (for instance, shuffling instead of picking up your feet) 
  • Poor balance
  • Urgency when you need to pee

Dementia with Lewy bodies (DLB)

Lewy bodies are tiny deposits of a protein that collect in your brain and prevent important cells there from "talking" with each other. They're named after the scientist who discovered them. Researchers are still trying to better understand why these proteins start clumping together, but they know they sometimes show up in other types of dementia, too.

DLB symptoms include:

  • Struggling to think clearly, make decisions, or pay attention
  • Seeing things that aren't there, known as visual hallucinations
  • Hearing or smelling things that aren't there (nonvisual hallucinations)
  • Having a hard time with language or numbers
  • Losing track of time or where you are
  • Physically acting out dreams (for instance, talking, walking, and kicking)
  • Movement issues (like tremors or moving more slowly than usual)

Parkinson’s disease dementia (PDD)

About 50% of people who live with Parkinson's disease, a nervous system disorder, notice at least a slight change in their memory and ability to think. Over time, this can worsen and make getting through your daily life more challenging.

Some signs of PDD include:

  • Short- or long-term memory issues
  • A hard time getting around places, especially if they're busy or crowded
  • Mood changes
  • Delusions (like strange beliefs or feeling like people are "out to get you")
  • Struggling to recall the names of everyday things

PDD is very similar to DLB. You can have a lot of the same symptoms, and researchers have found that Lewy bodies are often present in people with PDD, too. 

The phrase Lewy body dementia (LBD) is sometimes used to refer to both DLB and Parkinson's disease dementia.

Mixed dementia

As many as 1 in 10 people have more than one type of dementia. If so, you have what's called mixed dementia.

The two most common combinations are Alzheimer's and vascular dementia and Alzheimer's and DLB. 

Mixed dementia doesn't have its own unique symptoms. How your memory and thinking are affected will depend on the different types of dementia that you have. Having two sets of symptoms can make your overall condition more of a challenge to diagnose and treat. Your doctor may suggest several therapies, as well as medication, to manage your symptoms. 

Frontotemporal dementia (FTD)

If you or a loved one has FTD, a doctor has found cell damage in areas of the brain that control planning, judgment, emotions, speech, and movement.

Someone with FTD may have:

  • Personality and behavior changes
  • A sudden lack of inhibitions in personal and social situations
  • Challenges when trying to come up with the right words when speaking
  • Movement issues, like shakiness, unsteady balance, and muscle spasms

Young-onset dementia

Most people who are diagnosed with dementia are older. If you're diagnosed before the age of 65, you have what's called young-onset dementia or early-onset dementia. If so, memory loss is likely to be one of your first symptoms. You could also:

  • Keep asking the same questions over and over
  • Find it hard to follow steps, like when you're following a recipe 
  • Sometimes feel unsure of where you are, how you got there, or what the date is
  • Lose track of where you put things and not know how to find them
  • Avoid social situations, because they feel too hard

If you have early-onset dementia, getting an early diagnosis is helpful. Your doctor can start you on treatments that may help keep your symptoms from getting worse.

Huntington's disease

This is a brain disorder that's passed down through family members. While you or your loved one might have the gene for Huntington's disease at birth, symptoms don’t usually show up until ages 30 to 50.

The most well-known sign of Huntington's are uncontrolled movements that can affect any muscle in your body. But you can also get some of the same symptoms seen in other forms of dementia, including issues with:

  • Thinking and reasoning
  • Memory
  • Judgment
  • Planning and organizing
  • Concentration
  • Mood changes, like being anxious, depressed, or quick to anger 

Creutzfeldt-Jakob disease

This is a rare condition in which proteins called prions cause normal proteins in your brain to start folding into abnormal shapes. The damage leads to dementia symptoms that start suddenly and quickly get more severe.

You or your loved one might have:

  • Memory and concentration issues
  • Poor judgment
  • Confusion
  • Mood swings
  • Depression
  • Trouble sleeping
  • Twitching or jerky muscles
  • Trouble walking

Normal pressure hydrocephalus (NPH)

Cerebrospinal fluid (CSF) is a special fluid inside your body that sends nutrients to your brain cells and helps flush out waste. If it stops circulating the way it should and gets backed up, it can cause this type of dementia. NPH symptoms often start slowly, then worsen over a few months. They include:

  • Changes in how you walk (for instance, turning your toes outward)
  • Being unable to hold your pee
  • Being forgetful
  • Having issues with your focus
  • Thinking and making decisions slower than usual
  • Losing interest in activities you usually enjoy

NPH can be treated by draining extra fluid from your brain through a long, thin tube called a shunt. Many times, this improves symptoms within days.

Wernicke-Korsakoff syndrome (WKS)

A rare condition, WKS can happen when you don't get enough thiamine (vitamin B1). This vitamin is key to turning sugar into energy that your body can use. Without a proper amount, your brain cells get damaged. 

WKS is more likely to happen if you can't absorb all the nutrients you need to stay healthy. A common reason is alcohol abuse disorder. But WKS can also be caused by many other health conditions, including IBS, extreme morning sickness, and eating disorders.

Symptoms of Wernicke-Korsakoff syndrome include:

  • Memory issues 
  • A sense of amnesia (forgetting the past)
  • Feeling disoriented
  • Hallucinations 
  • Remembering things differently than they happened or having "made-up" memories
  • Being unsteady on your feet

Alcohol-related dementia

Regularly drinking alcohol for many years can shrink parts of your brain and cause a form of dementia. Unlike some other types, alcohol-related dementia may not get more severe over time. Treatment can make a big difference. 

Among the signs of alcohol-related dementia are:

  • Being easily distracted
  • Finding it hard to make decisions, problem-solve, or set goals
  • Emotional outbursts
  • A decrease in empathy (understanding how others may feel)
  • Lack of motivation

HIV-associated dementia

HIV (human immunodeficiency virus) puts you at risk of this kind of dementia. It's caused when the virus infects your brain. Over time, this can damage the important nerve cells there. 

Early symptoms of HIV-associated dementia include: 

  • Forgetting daily tasks, like a doctor visit
  • Feeling like you're thinking more slowly than usual
  • Finding it hard to focus
  • Struggling to feel steady on your feet
  • A change in handwriting

Managing your HIV may help improve dementia symptoms.

Chronic traumatic encephalopathy (CTE) dementia

Repeated head injuries, like concussions, can damage your brain over time. You're at higher risk of CTE dementia if you play a contact sport, like football, where you might take frequent blows to your head. It's also seen in military veterans and survivors of violence.

Some CTE dementia signs:

  • Headache or feeling pressure in your head
  • Struggling to learn new things
  • Memory loss
  • Poor sense of direction
  • Finding it hard to drive a car
  • Slowed decision-making
  • Mood or personality changes (like being quick to anger or feeling anxious and depressed)

If you have CTE dementia, you may not notice your own symptoms. A loved one may need to point them out to you.

Childhood dementia

One in 2,900 babies around the world are born with this genetic form of dementia. Sometimes, symptoms show up very quickly. Other times, they're not noticed until after puberty. But as in adult dementia, they can become more severe as time goes on.

Common signs of childhood dementia:

  • Memory loss
  • Struggling to learn, focus, or communicate with others
  • Feeling confused
  • Poor sleep
  • Behavior issues (like finding it hard to sit still)
  • Anxiety

If you feel your child shows any of these signs, talk to a doctor.

Posterior cortical atrophy (PCA)

This is a brain and nervous system condition that damages cells in the back of your brain. This is the area that helps with spatial reasoning (figuring out concepts like size and shape) and helps you understand what you see. PCA is often due to Alzheimer's disease, but other types of dementia can cause it, too.

If you have PCA, you could struggle with memory loss as well as:

  • Reading
  • Spelling
  • Doing math
  • Telling left from right
  • Using household objects or tools
  • Recognizing places or people you know
  • Guessing how far away an object is

Issues with your eyesight are often the first symptom of PCA.

Dementia is a broad term for many conditions that cause memory loss and make you less able to think well. If you notice any symptoms, see a doctor right away. Early treatment can often help slow down the disease.


How does your body warn you that dementia is forming?

As your thinking slows down, your body might too. An early symptom of dementia is often a slowed gait. You may also feel less coordinated and balanced when you move throughout your day.

What stage of dementia is sundowning?

Sundowning isn't a stage, but a group of symptoms that are common in people with dementia. From dusk until sunrise, dementia symptoms often get worse. You could have trouble sleeping, feel disoriented, or see things that aren't real.

Experts aren't sure what causes sundowning. But many strategies, from getting a lot of sunlight during the day to doing soothing, not stimulating, activities before bedtime, can help.