Dementia vs Delirium: Spotting the Difference

Dementia and delirium are two distinct medical conditions that are often confused with each other. Both of these conditions affect the mental functions of the patients, but they are entirely different from one another. It is essential for both medical professionals and caregivers to understand the differences between dementia and delirium to provide the best care possible.

In this article, we will discuss the difference between dementia and delirium, their symptoms, and ways to help distinguish them from one another.

What is Dementia?

Dementia is a term used to describe a decline in cognitive abilities that are severe enough to interfere with daily life activities. It is caused by damage and destruction of brain cells that results in a decline in memory, thinking, and reasoning. Dementia affects people of all ages, but it is most common in people over the age of 65.

Symptoms of Dementia

The symptoms of dementia can vary from person to person, but some of the most common symptoms include:

  • Memory loss
  • Difficulty communicating
  • Inability to perform simple tasks
  • Disorientation
  • Mood swings
  • Personality changes

The symptoms of dementia develop slowly over time, and they become more severe as the disease progresses. People with early-stage dementia may be able to function without assistance, but as the disease progresses, they may require around-the-clock care.

Types of Dementia

There are several types of dementia, including:

Type of Dementia Description
Alzheimer’s disease The most common type of dementia that causes memory loss, mood swings, and difficulty with communication and daily tasks.
Vascular dementia Caused by the blockage or damage of blood vessels in the brain, resulting in a decline in mental function.
Lewy body dementia A type of dementia that causes a decline in cognitive function, as well as visual hallucinations and tremors.

What is Delirium?

Delirium is a medical condition that involves sudden confusion and changes in mental function. It is caused by a disturbance in the brain’s function that results in a shift in awareness and an inability to focus. Delirium can affect people of all ages, but it is most common in older adults.

Symptoms of Delirium

The symptoms of delirium can develop quickly over a few hours or days, and they include:

  • Confusion
  • Disorientation
  • Difficulty focusing
  • Changes in level of consciousness
  • Memory problems
  • Agitation or anxiety
  • Difficulty sleeping

Delirium can be either hyperactive or hypoactive, depending on the individual’s symptoms. Hyperactive delirium involves agitation, restlessness, and rapid speech, while hypoactive delirium may involve lethargy, apathy, and a lack of response.

Causes of Delirium

Delirium can be caused by a variety of factors, including:

  • Infections
  • Dehydration
  • Medication side effects
  • Drug and alcohol withdrawal
  • Head injuries
  • Metabolic imbalances

It is essential to identify and treat the underlying cause of delirium to improve the patient’s symptoms and avoid further complications.

Spotting the Difference between Dementia and Delirium

While both dementia and delirium can cause confusion and changes in mental function, there are several key differences between the two conditions. Here are some of the ways to identify the difference between dementia and delirium:

Onset of Symptoms

The onset of dementia symptoms is gradual and develops over months or years, while the onset of delirium symptoms is sudden and can develop over hours or days.

Duration of Symptoms

The symptoms of dementia last for a long time and typically do not improve, while the symptoms of delirium come and go and can improve with treatment.

Level of Consciousness

Patients with dementia are usually alert and attentive, while those with delirium may become lethargic or have changes in their level of consciousness.

Severity of Symptoms

The symptoms of dementia are usually stable, while the symptoms of delirium can fluctuate in severity and may become worse at night or during times of stress or illness.

Symptom Presentation

Patients with dementia may forget recent events, while those with delirium may be unable to recall events from within the last few hours or days.

It is essential to consult with a medical professional to diagnose and treat both dementia and delirium properly.

Preventing Dementia and Delirium

While there is no cure for dementia, there are ways to lower the risk of developing the condition. Some of the ways to prevent dementia include:

  • Eating a healthy diet
  • Exercising regularly
  • Stimulating the brain with activities such as reading, puzzles, or socializing
  • Managing chronic conditions such as diabetes and high blood pressure

Delirium can be prevented by managing the underlying causes that contribute to the condition. For example, staying hydrated during times of illness and avoiding drugs and alcohol can reduce the risk of developing delirium.


Dementia and delirium are two distinct medical conditions that affect a significant portion of the population. It is essential to understand the differences between the two conditions and to seek professional medical care if symptoms manifest. By identifying and treating the underlying cause of each condition, patients can receive the necessary care and support to improve their quality of life.


What is the difference between dementia and delirium?

Dementia is a long-term decline in cognitive function resulting from damage or destruction to brain cells, while delirium is a sudden change in awareness and mental function that can fluctuate in severity.

What are the symptoms of dementia?

The symptoms of dementia include memory loss, difficulty communicating, an inability to perform simple tasks, disorientation, mood swings, and personality changes.

What are the symptoms of delirium?

The symptoms of delirium include confusion, disorientation, difficulty focusing, changes in the level of consciousness, memory problems, agitation or anxiety, and difficulty sleeping.

What causes delirium?

Delirium can be caused by infections, dehydration, medication side effects, drug and alcohol withdrawal, head injuries, and metabolic imbalances.

Can dementia and delirium be prevented?

Dementia can be prevented by eating a healthy diet, exercising regularly, stimulating the brain with activities, and managing chronic conditions. Delirium can be prevented by managing the underlying causes that contribute to the condition.


1. National Institute on Aging. (2017) Dementia.

2. American Psychiatric Association. (2013) Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5).

3. Inouye SK, Westendorp RGJ, Saczynski JS. (2014) Delirium in elderly people. The Lancet, 383(9920), 911-922.

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