Confusing delirium with dementia is not unheard of, as both conditions are characterized by confusion and disorientation and share several other symptoms. But they're caused by different circumstances, and have distinct diagnoses and treatment. Most importantly, delirium is a temporary and reversible condition, while a person suffering from dementia is seldom cured of it.

Comparison chart

Delirium versus Dementia comparison chart
Edit this comparison chartDeliriumDementia
About Temporary state of confusion and disorientation that may last for a few days to a few months. Not a specific disease, but rather a term that refers to symptoms of mental and communicative impairment found in a variety of brain conditions and diseases, including Alzheimer's. About 20% of dementia can be reversed.
Occurrence Any age. Percentage of elderly suffering from some form of dementia increases with age, with 2% of those aged 65-69, 5% of those aged 75-79, and over 20% of those aged 85-90 experiencing symptoms. One third of those 90+ have moderate to severe dementia.
Causes Illness (including dementia), fever, infection, medications, oxygen deprivation, sensory impairment, drug or alcohol abuse or withdrawal, body chemical disturbances, poor nutrition, dehydration, poisoning Dementia can be caused by a variety of illnesses, some potentially very treatable (e.g., nutritional deficiency), others—like Alzheimer's—not. Age is not the cause of dementia, but rather correlated with it.
Symptoms Reduced awareness or alertness, changes in perception, inability to focus, confusion, short-term memory loss, disorientation, difficulty communicating, changes in sleep patterns or emotions, hallucinations Memory loss is the earliest and most common sign. Irritability, depression, and other personality changes are also common. In more severe or worsening cases, language difficulties may occur, and spatial understanding deteriorates.
Prognosis Temporary and reversible; full recovery is common. Depending on the root cause, some dementia (about 20%) may be treated and even cured. However, most dementia is related to Alzheimer's, which is incurable.
Diagnosis Mental status assessment, physical and neurological exams, laboratory tests Mental status assessment, cognitive and neuropsychological tests, neurological evaluation, brain scans, laboratory tests, psychiatric evaluation
Treatment Starting, stopping, or changing medications; treating underlying medical and mental disorders; sensory aids; therapy; orientation aids like clocks and calendars; maintaining a calm and comfortable environment Depends on the cause. If treatable or reversible, may be as simple as changing medication dosage or taking a supplement.
Curable Yes. Usually, no.
Prevention Avoiding trigger situations and substances; maintaining adequate nutrition, hydration, and sleep patterns; using sensory and mobility aids, if necessary. Cannot be prevented with certainty. Healthy eating, staying social, exercising / playing sports with low risk of brain injury, solving puzzles, continuing education may all help, however.
Onset Rapid: Appears quickly, recovers soon Typically prolonged; progressively worsens

What is Delirium?

Delirium is a temporary mental state characterized by confusion and disorientation, difficulty communicating, reduced awareness, and changes in perception. It can be caused by illnesses or infections, alcohol or drugs, sensory impairment, or abnormalities in body chemistry or nutrition. It is possible for an otherwise healthy person to feel delirious for a short time after waking up from surgery. Delirium is reversible, and most people who suffer from it make a full recovery.

What is Dementia?

As most dementia is associated with Alzheimer's, dementia typically worsens with age. Unlike delirium, which is reversible, dementia is frequently caused by permanent damage to the brain's nerve cells. This damage can be caused by things like other illnesses, injuries, and even the genetic make-up of a person. Some dementia is treatable and even curable, but in general it affects different people differently. In general, a person with dementia is not likely to get better; the treatment is only for alleviating symptoms and maintaining an adequate quality of life.

Types of Dementia

Most types of dementia are progressive and continue to get worse. These include Alzheimer's disease (exact cause unknown; associated with brain protein plaques and tangles), Lewy body dementia (associated with abnormal clumps of brain protein), and fronto-temporal dementia (caused by the breakdown of nerve cells in certain lobes). Other disorders associated with dementia include Huntington's disease, traumatic brain injury, HIV, Lyme disease, strokes, multiple sclerosis, Pick's disease, Parkinson's disease, and Creutzfeldt-Jakob disease.


A number of illnesses and physical conditions can cause delirium. These include fever, infection, sensory impairment, oxygen deprivation, poor nutrition, dehydration, withdrawal from alcohol, illegal drugs or medications - interactions with SSRI like Zoloft, Lexapro, and other drugs may cause temporary delirium even within the prescribed dose. A person may also experience delirium while under the influence of drugs (legal or illegal) or alcohol.

Dementia is caused by brain damage, which itself can be triggered by numerous conditions. Like delirium, it can be caused by infections, substance abuse, or poor diet; however, dementia is more commonly associated with serious illnesses like Alzheimer's disease, Huntington's disease, or Pick's disease. Alzheimer's disease is the most common type of dementia, and genetics and/or environmental conditions could affect its development, but its exact cause is still unknown.


Delirium and dementia share many of the same symptoms, but they differ in their onset and duration — delirium comes on quickly and resolves within a week, but dementia typically appears over a longer period of time and cannot be reversed.

People who are delirious display sudden, often drastic changes in awareness, alertness, mood, short-term memory, and communication. They are disoriented and can forget where they are or why they are in a certain place (say, a hospital). Sometimes they become fixated on a certain concern or question such as, "Where am I?" or even something nonsensical. Or they may have a hard time focusing on external stimuli like the reasoning of other people in the room. They sometimes experience hallucinations and can have disorganized thinking. The video below is an example of delirium of a hospitalized patient:

Dementia, on the other hand, is almost always a progressive condition that manifests over a period of months, years, or even decades. Most dementia sufferers are over the age of 60. People who eventually develop full-blown dementia may initially notice themselves becoming more forgetful or misplacing things more often — but they might blame it on the natural aging process. Eventually they may lose the ability to recognize their family and friends or even their own selves.

Other symptoms of dementia include difficulty performing tasks, particularly ones that were formerly routine or easy; difficulty communicating, such as forgetting words or losing the ability to form sentences; changes in personality or emotions; and impaired senses and motor functions. A person with severe dementia may show poor judgment and behave inappropriately, even in public places. What this video to learn how to identify signs of dementia:


Physicians diagnose delirium and dementia on a case-by-case basis, but both typically involve examining a patient's physical and mental histories and by performing physical and neurological tests. Neurological tests may focus on the patient's cognitive skills, motor functions, and sensory perceptions.

In the case of dementia, more extensive laboratory and imaging tests are necessary to confirm the presence of brain damage that causes the condition.

The costs of these diagnostic techniques vary by physician, institution, and insurance policy.


Because delirium is actually a symptom of other conditions, it can be alleviated by treating the specific underlying conditions. If a person suddenly develops delirium, emergency medical treatment should be sought immediately, as it could be a sign of a more serious condition.

A person who becomes delirious as a result of taking a sedative medication, for example, is likely to get better in a short period of time if they stop taking the medication. People who experience confusion or disorientation as a result of sensory difficulties may benefit from properly fitted glasses or hearing aids.

More serious cases of delirium can be treated with reality aids like clocks, calendars, a familiar and comfortable environment, and the reassurance and calm reasoning of family and friends. Some patients may require hospitalization as they recover so they do not harm themselves or others. Most people with delirium get better within a week and go on to make a full recovery, but it may take additional time to regain full mental function.

Dementia is frequently a progressive and irreversible condition, so treatment is mostly focused on alleviating the symptoms of patients and slowing the rate of its progression. Dementia is also associated with a number of other diseases and illnesses, and should be treated on a case-by-case basis. Unless it appears suddenly, it usually does not require emergency care; treatment should be initiated through the patient's regular doctor.

Some dementia patients may need to take psychiatric medications, such as anti-psychotics, mood stabilizers, or stimulants, to keep their behavior or emotions under control. Because dementia is usually a long-term condition, and because patients display a varying severity of symptoms, the exact treatments and costs of those treatments vary by physician, institution, and insurance policy.

How to Support Patients of Dementia

While dementia cannot be cured, support from friends and family members goes a long way in alleviating the symptoms and making life easier for the patient.

Dementia patients can benefit from the involvement of family, friends, or caregivers who spend time with them. Patients may become confused about their surroundings and require calm reassurance, or they may require assistance with everyday tasks like eating and bathing. People with mild dementia often remain in their homes, but more severe cases frequently require hospitalization in a nursing home or special care facility where they can receive around-the-clock supervision and treatment.

Some of the sensory impairments associated with dementia, such as vision or hearing loss, can be alleviated with the use of properly fitted sensory aids like glasses or hearing aids. Labels and reminders, medication organizers, and special large-button phones and remote controls may also be helpful. It is also important to maintain a clutter-free and organized home, as many people with dementia have difficulty with coordination or have other diseases that affect mobility, like arthritis.

Some researchers believe people can reduce their risk of developing dementia by keeping their minds active — playing puzzle games, reading challenging material, etc. — but this alone will not prevent the condition.


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