Delirium vs. Dementia: What's the Difference?

By Eric Carter

When it comes to ensuring that your loved one receives the absolute best in support and services, it's crucial to understand that cognitive changes, like delirium and dementia, require just as much care as physical conditions, like heart disease and high blood pressure.

Cognitive issues can affect a senior's ability to think, reason, or remember — and become much more common as we age. In fact, around one-third of seniors who arrive at hospital emergency rooms are found to be suffering an episode of delirium. And 1 in 6 women and 1 in 10 men past the age of 55 will go on to develop dementia.

To best support your loved one, it's important to know how to identify both delirium and dementia. What are the signs and symptoms? What causes these cognitive issues? And how are these conditions different? Let's take a closer look at delirium vs. dementia in seniors.

Delirium in the Elderly

Delirium means "sudden confusion," and reflects a serious disturbance in thought, mood, and behavior. All of the sudden, your loved one may no longer behave like themselves — and you may not immediately recognize the cause. Some common signs that indicate an episode of delirium include: 

  • Mood changes: Anger, agitation, anxiety, depression, suspicion, and fear are all common in delirium
  • Changes in speech: Your loved one may have slurred speech or suddenly start saying things that make no sense
  • Sleep changes: Seniors may become more active at night or sleepy during the day
  • Disorientation and confusion: A senior might not know where they are or what they are doing
  • Visual hallucinations: Your loved one may report seeing things that aren't there
  • Physical issues: They may report incontinence, chills, fever, or pain

If these signs and symptoms come about over the course of a few days or hours, then it's important to seek medical treatment immediately.


Delirium is a common condition in seniors and is caused by various factors. The Health in Aging Foundation breaks down the causes of delirium into an acronym (DELIRIUM):

  • D - Drugs and medications
  • E - Electrolytes imbalance, as caused by thyroid issues or dehydration
  • L - Lack of drugs, such as when a senior is given inadequate pain medication or goes off medication suddenly
  • I - Infections like UTIs can cause delirium when untreated
  • R - Reduced sensory input, such as when a senior can no longer see or hear clearly
  • I - Intracranial issues like stroke, tumors, or hemorrhage
  • U - Urinary problems like constipation or the inability to urinate
  • M - Myocardial or lung conditions like COPD or congestive heart failure

In addition, delirium is very common following surgery. Because it's one of the first signs that a person is experiencing a life-threatening emergency, like a stroke or heart attack, seeking immediate emergency care is crucial.


When you bring a loved one to the hospital for symptoms of delirium, medical professionals will carefully test and examine to determine the cause of the issue. For example, if the delirium is attributed to a change or reaction to the medication, they can attempt to modify the medication to bring their loved one back into balance. If the delirium is caused by a heart attack or stroke, they will treat the underlying condition as quickly as possible.

Because the causes of delirium vary so much from case to case, treatment will depend on what is causing the episode. 

Dementia in the Elderly

Because delirium and dementia both affect cognitive ability, it's easy to get these conditions confused. In fact, individuals with dementia are more likely than others to experience episodes of delirium. However, while delirium refers to a sudden onset of confusion and disorientation, dementia is a progressive condition. It can occur over the course of months and years. Unlike delirium — which usually goes away fairly quickly with treatment — dementia remains a long-term condition.

The most common form of dementia (around 60% to 80% of cases) is Alzheimer's disease. Because dementia can affect different parts of the brain, the way dementia is manifested might vary significantly from person to person. And because it's a progressive illness, symptoms usually worsen over time. These are some of the most common signs and symptoms of dementia:

  • Memory loss
  • Difficulty with activities of daily life (i.e. shopping, paying bills, and cooking)
  • Changes in mood
  • Changes in the ability to problem-solve
  • Increasing difficulty with focusing or paying attention
  • Changes in personality


While delirium often comes about due to acute injury or illness, dementia is usually associated with the dysfunction and death of neurons (nerve cells in the brain). As brain cells lose the ability to communicate with one another, a senior may start to lose their ability to reason, remember, and think clearly.

The symptoms of dementia are traced to anatomical changes in the brain and are caused by a combination of genetics, lifestyle factors, and environmental factors. For example, there may be a relationship between changes in the brain and other health conditions like heart disease and high blood pressure.


When the underlying causes of delirium are addressed, the episode will often resolve. Unfortunately, there is no such cure for dementia. Those with Alzheimer's and other forms of dementia can be supported with medications that help slow down and lessen symptoms. A caring and supportive team can help those with dementia manage triggers and create a supportive environment.

Dementia vs Delirium: Key Differences

When it comes to these separate cognitive conditions, it's important to realize that an individual can experience both at the same time. For example, if your loved one has Alzheimer's disease but then experiences an episode of extreme hallucinations, radical mood changes, and unusual confusion and disorientation, then they may need to seek medical treatment for delirium.

However, in general, here are the key differences to look out for:

  • Memory: One of the major differences between delirium and dementia is that, while delirium affects attention and concentration, dementia is primarily associated with memory loss.
  • Attention: Though seniors with dementia may have some issues with attention in the late stages of the condition, for the most part, they are able to remain relatively attentive. By contrast, individuals in a state of delirium will be easily distracted, unable to concentrate, and generally going in and out of consciousness.
  • Speech: Although individuals with dementia in late stages may have difficulty putting their thoughts to words, they usually won't demonstrate the sudden slurred speech common to delirium.
  • Hallucinations: Though hallucinations occasionally occur with dementia, they are very common with delirium.
  • Illness: Delirium is often caused by illness, surgery, or drugs. Those with dementia often will have no signs of physical illness or conditions.

Providing Support for Cognitive Issues

As a loved one or caregiver, you can make all the difference by noticing any changes in your loved one's thinking, reasoning, or behavior. If your loved one's memory and judgment seem to be deteriorating over time, then it might indicate the progressive cognitive decline associated with dementia. In these cases, it's important to know when to seek professional care for your loved one.

If, however, your loved one experiences a sudden onset of confusion at home, in the hospital, or after surgery — then it's important to alert emergency medical professionals right away. Want to learn more about how to help your loved one remain safe and healthy? Please don't hesitate to contact us today.

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Tags: Alzheimer's & Dementia