Delirium vs Dementia: What's the Difference?

In the realm of cognitive health conditions, two common but frequently misunderstood terms are dementia and delirium. And if you're providing care for a loved one, it can be difficult to distinguish between the two. Granted, their shared symptoms can be confusing, but like two pieces of a larger puzzle, each has its own unique shape and place in the cognitive health landscape. 

As our bodies age, so do our brains. These changes in the brain include a decrease in blood flow to particular brain areas, shrinkage of brain regions, inflammation in the brain, or the death of nerve cells. Collectively, these changes can result in episodes of either delirium or dementia. But what is different between the two?

How to tell the difference between delirium and dementia

If you're a caregiver or helping to support an older adult, differentiating delirium versus dementia can be challenging, as both conditions can cause confusion and cognitive impairment. Our best advice is to consult with a medical professional immediately should you suspect either condition. Here's a quick overview of how they differ:

• Acute onset of symptoms: Delirium often comes on suddenly, over hours or days, whereas dementia usually begins with subtle symptoms that progress slowly over months or years.
• Changes in symptoms: In delirium, the severity of symptoms can change significantly over a short period, often worsening in the evening. In contrast, the symptoms of dementia tend to be stable or follow a steady decline.
• Attention: Individuals with delirium often have a marked reduction in attention and may be easily distracted. Although attention can also decrease in later stages of dementia, it's usually preserved in early stages.
• Fluctuations in alertness: In delirium, consciousness or alertness often fluctuates during the day, with periods of hypersomnia (increased sleepiness) and hyperarousal. In dementia, fluctuations in alertness are less common unless delirium is also present.
• Memory loss: Memory loss is a core feature of dementia, especially of recent events or newly learned information. In delirium, memory loss can also occur, but it might not be as prominent or consistent.
• Reversibility: Most of the time, delirium is temporary and reversible if the underlying cause is identified and treated, whereas dementia is a chronic, progressive condition.

Is it possible to have delirium and dementia at the same time?

Delirium superimposed refers to the onset of delirium in a person who already has a pre-existing cognitive impairment, most often dementia.

For example, an individual with dementia might have changes in the brain, making them more susceptible to developing delirium in response to certain triggers such as a new medication, infection, surgery, or even a change in environment.

At the same time, a delirium episode can exacerbate the symptoms of an underlying dementia, making them appear worse than they actually are.

Delirium is an acute, sudden change in mental function that goes well beyond the usual forgetfulness of aging. It's often characterized by confusion, disorientation, inability to focus, hallucinations or altered perceptions of reality. Because it's usually such an abrupt change in mental state, it's often considered a medical emergency and sometimes even mirrors the symptoms of many critical conditions such as stroke, cancer or infections.

Unlike dementia which is a chronic, progressive cognitive disorder, delirium comes on suddenly, usually within hours or days. It is often caused by a physical or mental illness, and can be temporary and reversible. However, delirium could also be a signal that the brain is undergoing some damage. Factors such as advanced age, prior brain disorders, visual or hearing impairment, and severe illness can make older adults more prone to developing delirium. Its effects can be frightening not only to the person suffering from it, but also to those around them.

Delirium usually develops in older adults and can appear similar to Alzheimer’s disease, Lewy body dementia, or vascular dementia even though they are distinct diagnoses.

Types of delirium

There are three types of delirium: hyperactive, hypoactive, and mixed.

• Hyperactive delirium is the most recognizable type, characterized by symptoms such as restlessness, agitation, and rapid mood changes. Patients with this type of delirium can be hyper-vigilant and may also experience hallucinations or delusions.
• Hypoactive delirium, the most common type in older adults and often missed, presents very differently. Patients with this type of delirium typically appear sleepy, lethargic or indifferent. They may not respond to questions or stimuli normally, may seem unfocused and can even slip in and out of consciousness. It is often mistaken for depression or general decline due to age.
• Mixed delirium, as the name suggests, is a combination of symptoms from both hyperactive and hypoactive delirium. Patients may fluctuate between states of hyperactivity and hypoactivity, which can be quite confusing for their caregivers and healthcare providers to manage and diagnose. Each type, however, is connected by a common thread of sudden cognitive impairment, whether it manifests as hyperactivity, hypoactivity, or a combination of the two. Prompt diagnosis and treatment are crucial to manage deliriumPrimary symptoms of delirium

Symptoms of delirium

Though some symptoms vary depending on which type of delirium a person has, there are several primary symptoms many people experiencing delirium may show. 

• Impaired cognition: This symptom often exhibits as severe confusion, disorientation or disorganized thinking. Patients may not be aware of their surroundings, or find it challenging to follow conversations.
• Altered behavior: This could range from hyperactivity, where the individuals seem restless and agitated, to hypoactivity, where they might be sluggish or immobile. There may also be changes in their speech patterns and coordination.
• Hallucinations or delusions: Some patients might have an altered perception of their reality, and in extreme cases, even see or hear things that aren't there. These can be vivid and often distressing, adding to their confusion and fear.
• Rapid and unpredictable shift in symptoms: The symptoms of delirium can shift rapidly and unpredictably. Patients may seem fine one moment and confused the next. This swing between extremes is often worse at night, a phenomenon known as "sundowning".
• Difficulty staying alert or awake: Patients may alternate between periods of extreme drowsiness and alertness.
• Changes in sleep patterns: This could include problems falling asleep or staying asleep, abnormalities in the sleep-wake cycle, being awake at night, or other irregular sleep patterns.
• Mood swings: Rapid changes in mood such as sudden fear, anxiety, depression, or apathy can also indicate delirium. Patients might become unusually quiet and withdrawn, or be anxious and unfocused.
• Short-term memory issues: While long-term memory remains relatively intact, patients might struggle with remembering recent events or learning new information. They may repeat the same questions, forget recent conversations, or misplace items.

What causes delirium to occur?

Delirium can be caused by anything that strains the body’s homeostasis or balance, especially in older adults. One of the most common risk factors of delirium is being over 70. It is also more prevalent in males.

• Infections: Older adults are more susceptible to infections such as a urinary tract infection or pneumonia, which have been posited to cause delirium.
• Medications: Certain medications, especially those with sedatives, narcotics, or those used to treat Parkinson's and depression, can trigger delirium.
• Metabolic imbalances: Electrolyte imbalances, thyroid dysfunction or significant changes in body chemistry caused by conditions like kidney or liver disease, hypoglycemia, or thyroid disease can lead to delirium.
• Surgery or medical procedures: Delirium can occur after surgery or other major medical procedures, particularly those that involve anesthesia or a stay in an intensive care unit.
• Alcohol or drug withdrawal: Withdrawal symptoms from alcohol or certain types of drugs can provoke delirium.
• Severe illness: Serious illnesses like heart disease, lung disease, or severe pain can precipitate delirium, as the body responds to the condition.
• Environmental factors: Changes in the environment such as moves to a new home or hospitalization can trigger delirium in older adults, especially if they also have dementia.

It's important to note that delirium often has more than one cause in a single patient, and it's usually a combination of factors that leads to the condition.

Things like medication side effects, surgery, infection, dementia, intoxication or withdrawal can cause delirium. But it can also be caused by constipation, lack of sleep, pain, or even imbalances like low sodium.  

How is delirium diagnosed?

Delirium can only be diagnosed by a medical doctor. To accurately diagnose, a doctor will do a thorough physical examination, blood and urine tests, imaging tests (MRI, CT, X-rays), and a review of the person’s complete medical history. Test might include:

• Cognitive tests: These are simple tasks assessed by healthcare providers to determine a patient's ability to pay attention, remember and think clearly. For instance, the patient may be asked to recall a list of numbers, or indicate the current time and place.
• Assessment scales: One widely used test for delirium is the Confusion Assessment Method (CAM), which evaluates whether there is an acute change in mental status, inattention, disorganized thinking, and an altered level of consciousness.
• Lab tests and imaging scans: Blood and urine tests can help identify potential infections, metabolic imbalances or other underlying conditions that could lead to delirium. If necessary, brain imaging tests, such as computerized tomography (CT) or magnetic resonance imaging (MRI) scans, or electroencephalograms (EEGs), might be conducted to check for brain abnormalities.
• Medication and substance review: A comprehensive review of all medications and substances the patient is using, including prescribed drugs, over-the-counter medications, supplements, alcohol, and narcotics. This can help clinicians determine if the delirium could be a result of drug interactions or withdrawal symptoms.

It can be difficult to diagnose delirium because of the many things that can cause delirium and how closely it may resemble other conditions. But delirium can be dangerous and often indicates other underlying issues, so no episode of delirium should ever be ignored. 

Can delirium be treated?

The short answer is: it depends. The treatment of delirium primarily focuses on addressing the underlying cause. This can include treating an infection, adjusting or discontinuing medications that may be contributing to delirium, addressing metabolic imbalances, or treating alcohol or drug withdrawal symptoms. Here are some common treatment strategies:

• Medical Treatment: If infections, metabolic disturbances, dehydration or withdrawal from certain substances are at play, these will need to be treated effectively.
• Medication Review: Often, a careful review of medications is required to identify those that could be causing or contributing to delirium. In some cases, medications may be reduced, discontinued or switched.
• Supportive Care: This can include ensuring the patient is hydrated and well-nourished, helping them maintain a normal sleep-wake cycle, and reducing use of catheters or physical restraints which can escalate agitation and confusion.
• Environmental Modifications: Providing a quiet and well-lit environment with visible clocks and calendars can be helpful. Frequent orientation to person, place, time and situation may also be beneficial. In some cases, having a family member or caregiver present can soothe a patient with delirium.
• Psychotherapy and behavioral interventions: Gentle reassurance, distraction, and relaxation techniques can help in managing both anxiety and the behavioral symptoms of delirium.
• Temporary use of medications: In some cases, to control severe symptoms or to prevent harm to the patient or others, medications may be used. However, these are usually a last resort due to potential side effects.

Once delirium is diagnosed and the underlying cause is identified, a doctor may decide antipsychotic medications (such as haloperidol) are best to manage the delirium or just specialized care and monitoring until the delirium ends. There are no FDA approved treatments specifically for delirium, and most medical professionals believe prevention is the best approach. 

Dementia is a general term for a decline in mental ability severe enough to interfere with daily life. It's not a specific disease but rather a term that encompasses a wide range of medical conditions - including Alzheimer's disease - characterized by the impairment of brain functions such as memory, thinking, and reasoning skills. Symptoms also often include changes in personality, mood, and behavior.

Dementia typically affects older adults and is caused by damage to brain cells that affects their ability to communicate, which can affect thinking, behavior and feelings. It's important to note that developing dementia is not a part of normal aging, but the risk does increase with age.

Dementia is a progressive condition, meaning it worsens over time, and currently, there is no cure. However, treatments are available which can slow its progress and improve the quality of life for those affected. Though the most common type of dementia is Alzheimer’s disease, there are many other types of dementia like frontotemporal dementia, or Lewy Body dementia.  

To read more about the types of dementia, check out our article on the 10 Types of Dementia.

Symptoms of dementia

While the causes of dementia vary, depending on the type a person has, so do the symptoms. However, some common early warning signs of dementia, regardless of type, may include:

• Memory loss: This is often one of the first signs of dementia. People may forget recent events or information and may ask for the same information repeatedly.
• Difficulty with complex tasks: Simple tasks that require sequential steps, like cooking a familiar recipe or paying bills, can become challenging.
• Difficulty with words and conversation: Individuals may struggle to find the right words, repeat themselves, or have difficulty following conversations.
• Getting lost in familiar places: Navigating through previously well-known areas or forgetting the way home can be a sign of dementia.
• Poor judgment: This can manifest as difficulty with decision making, falling for scams easily, or ignoring personal hygiene.
• Mood and personality changes: You may see unexplainable shifts in mood and demeanor. This could range from increased agitation, becoming fearful or suspicious, to sudden bouts of depression.
• Misplacing things: People with dementia often put things in unusual places and can't retrace their steps to find them. They might also accuse others of stealing.
• Confusion about time or place: Individuals with dementia can lose track of dates, seasons, and time. They might also forget where they are or how they got there.
• Withdrawal from social activities: An individual may start to withdraw from hobbies, social activities, or projects in the workplace because they have trouble keeping up.
• Difficulty performing activities of daily living (ADL): As dementia progresses, it can become more difficult for individuals to carry out daily activities that they've done independently before. This may include activities such as eating, bathing, dressing, toileting, or maintaining personal hygiene. The decline in the ability to manage these tasks can be gradual and often depends on the stage and type of dementia.Each person with dementia may experience these symptoms differently, and the progression of the symptoms can vary based on the type of dementia and the individual.

How is dementia diagnosed?

Dementia is diagnosed in a similar way as delirium by a medical doctor. A doctor may do a thorough physical, perform a psychological assessment, order blood, urine tests or imaging tests (MRI, CT, X-rays), and complete a review of the person’s complete medical history to make an official diagnosis. Unlike the process for diagnosing delirium, standard tests for diagnosing dementia might include:

• Medical history: The doctor will perform a detailed review of the patient's medical history and symptoms. They'll likely ask about recent illnesses or other medical conditions, family medical history, and any difficulties the patient is having with daily activities.
• Physical examination: Doctors conduct a physical examination to check for any physical signs of dementia or clues to what might be causing symptoms.
• Neurological tests: These tests can help doctors assess balance, sensory function, reflexes, and other neurological functions. It can also help identify signs of strokes, tumors, or other medical conditions that can impact brain function.
• Cognitive tests: These tests measure memory, problem-solving abilities, attention span, language skills, and math skills. They help identify patterns reflective of specific types of dementia.
• Brain scans: Imaging studies, such as magnetic resonance imaging (MRI), computed tomography (CT), or positron emission tomography (PET), can help identify strokes, tumors, or other structural and metabolic brain changes.
• Lab tests: Blood tests can help rule out other potential causes of memory loss and confusion, such as thyroid disorders or vitamin deficiencies.

Can dementia be treated?

While there is no cure for most types of dementia, there are treatments to help people manage symptoms and improve their quality of life. These can include antidepressants, antipsychotics, Alzheimer’s-specific drugs like Aducanumab and Lacanemab, and cholinesterase inhibitors like Aricept or Exelon. The specific treatment plan will depend on the type of dementia and its causes. Here's a look at some common treatment methods:

• Medications: Several medications can temporarily improve symptoms by influencing the chemicals that carry messages between brain cells. Donepezil, rivastigmine, or galantamine are used to treat Alzheimer's disease by attempting to regulate acetylcholine, a chemical messenger involved in memory and judgment. Memantine is another drug that's often used to treat moderate to severe Alzheimer's disease.
• Therapies: Non-drug interventions can help manage some symptoms of dementia. For example, cognitive behavioral therapy may improve depression or anxiety. Occupational therapy might help teach coping behaviors to prevent accidents, manage behavior, and plan activities.
• Lifestyle adjustments: Regular physical exercise, a healthy diet, avoiding alcohol and smoking, and maintaining an active social life may slow the progression of dementia in some cases. Cognitive stimulation activities, such as puzzles, reading, or games, can also assist with cognitive function.
• Care and safety considerations: Creating a safe and supportive environment can improve the quality of life for people with dementia. Memory care communities are known for their innovative programming that provides engagement, support and activity for patients with memory diagnoses.

While treatments may improve symptoms and the quality of life for some people with dementia, it's important to remember they do not stop or reverse the underlying disease process. Each person with dementia may have their treatment plan tailored to their specific symptoms and needs.

If you've made it this far - congratulations! You've taken the first step toward providing great care for yourself or a loved one. Both dementia and delirium can be tough to diagnose and treat, but understanding how they are similar and how they differ is a great first step.