Delirium vs. Delusion — What's the Difference?
Edited by Tayyaba Rehman — By Fiza Rafique — Updated on October 25, 2023
"Delirium" is a temporary state of mental confusion, while "Delusion" is a fixed, false belief contrary to reality.
Difference Between Delirium and Delusion
Table of Contents
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Key Differences
Delirium and Delusion are both terms related to the realm of mental health, but they serve to describe different conditions. Delirium is a transient and usually acute disturbance of consciousness, characterized by confusion, difficulty focusing, and memory problems. On the other hand, Delusion is a steadfast, false belief held despite evidence to the contrary.
Delirium can arise from a myriad of causes, ranging from infections, drugs, or even a response to surgery. This temporary state can manifest with symptoms like restlessness, hallucinations, and a fluctuating level of consciousness. Conversely, Delusion is more about belief: for instance, someone might believe they're a historical figure despite overwhelming evidence proving otherwise.
An individual in Delirium often appears disoriented, might not recognize familiar places or faces, and their symptoms can vary in intensity throughout the day. Delusion, meanwhile, is generally consistent, and an individual with a delusion is usually certain about their false belief, regardless of what others say.
Importantly, Delirium is typically reversible, with the underlying cause, such as an infection, being treated. It's an altered state of mind rather than a firm belief system. Delusion, on its part, is often a symptom of psychiatric disorders, such as schizophrenia, and may require different forms of intervention, including therapy or medication.
In summary, while both Delirium and Delusion deal with altered perceptions of reality, the former is an acute, often reversible state of confusion, while the latter is a steadfast, false belief not aligned with reality.
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Comparison Chart
Primary Meaning
An acute, transient disturbance of consciousness.
A steadfast, false belief held despite evidence to the contrary.
Manifestation
Confusion, restlessness, fluctuating consciousness.
Firm belief in something false.
Potential Causes
Infections, drugs, post-surgery reactions.
Psychiatric disorders like schizophrenia.
Duration and Nature
Temporary and often reversible.
More persistent and fixed.
Treatment
Treat the underlying cause.
Therapy, medication for underlying psychiatric conditions.
Compare with Definitions
Delirium
A state of heightened excitement or ecstasy.
The crowd's delirium after the final goal was palpable.
Delusion
A false belief held despite contradictory evidence.
He held the delusion that he could fly without wings.
Delirium
An extreme emotional disturbance.
The shocking news sent her into delirium.
Delusion
A mistaken or unfounded opinion.
The idea of finding a utopia on Earth is a delusion to many.
Delirium
An acute disturbance of consciousness.
The fever induced a state of delirium in the patient.
Delusion
A symptom of certain psychiatric disorders.
The patient's delusion of grandeur concerned the doctors.
Delirium
Temporary confusion and reduced awareness.
After the surgery, she experienced brief delirium.
Delusion
An erroneous perception of reality.
Despite all evidence, she held onto her delusion.
Delirium
Delirium, also known as acute confusional state, is an organically caused decline from a previous baseline mental functioning, that develops over a short period of time, typically hours to days. Delirium is a syndrome encompassing disturbances in attention, consciousness, and cognition.
Delusion
A deception or false hope.
The dream of endless wealth turned out to be a delusion.
Delirium
A temporary state of mental confusion and fluctuating consciousness resulting from high fever, intoxication, shock, or other causes. It is characterized by anxiety, disorientation, hallucinations, delusions, and incoherent speech.
Delusion
A delusion is a fixed belief that is not amenable to change in light of conflicting evidence. As a pathology, it is distinct from a belief based on false or incomplete information, confabulation, dogma, illusion, or some other misleading effects of perception as individuals with these beliefs are able to change or readjust their beliefs upon viewing the evidence for these beliefs.
Delirium
A state of uncontrolled excitement or emotion
Sports fans in delirium after their team's victory.
Delusion
An idiosyncratic belief or impression maintained despite being contradicted by reality or rational argument, typically as a symptom of mental disorder
The delusion of being watched
Delirium
(symptom) A temporary mental state with a sudden onset, usually reversible, including symptoms of confusion, inability to concentrate, disorientation, anxiety, and sometimes hallucinations. Causes can include dehydration, drug intoxication, and severe infection.
Delusion
The act or process of deluding.
Delirium
Wild, frenzied excitement or ecstasy.
Delusion
The state of being deluded.
Delirium
A state in which the thoughts, expressions, and actions are wild, irregular, and incoherent; mental aberration; a roving or wandering of the mind, - usually dependent on a fever or some other disease, and so distinguished from mania, or madness.
Delusion
A false belief or opinion
Labored under the delusion that success was at hand.
Delirium
Strong excitement; wild enthusiasm; madness.
The popular delirium [of the French Revolution] at first caught his enthusiastic mind.
The delirium of the preceding session (of Parliament).
Delusion
(Psychiatry) A false belief or perception that is a manifestation of a mental illness
Delusions of persecution.
Delirium
State of violent mental agitation
Delusion
A false belief that is resistant to confrontation with actual facts.
Delirium
A usually brief state of excitement and mental confusion often accompanied by hallucinations
Delusion
The state of being deluded or misled, or process of deluding somebody.
It is far better to grasp the universe as it really is than to persist in delusion, however satisfying and reassuring.
Delirium
Rapid and incoherent speech or thoughts.
His delirium made it hard to understand his needs.
Delusion
That which is falsely or delusively believed or propagated; false belief; error in belief.
Delusion
A fixed, false belief, that will not change, despite evidence to the contrary.
Delusion
The act of deluding; deception; a misleading of the mind.
Delusion
The state of being deluded or misled.
Delusion
That which is falsely or delusively believed or propagated; false belief; error in belief.
And fondly mourned the dear delusion gone.
Delusion
(psychology) an erroneous belief that is held in the face of evidence to the contrary
Delusion
A mistaken or unfounded opinion or idea;
He has delusions of competence
His dreams of vast wealth are a hallucination
Delusion
The act of deluding; deception by creating illusory ideas
Common Curiosities
Is a Delusion always a sign of mental illness?
While Delusion is often linked to psychiatric disorders, not all false beliefs are indicative of mental illness.
Can Delirium be caused by medications?
Yes, certain medications can induce Delirium.
Is Delirium always noticeable?
Symptoms of Delirium can be subtle, especially in its early stages, and might be missed.
Can both conditions coexist in a person?
Yes, a person can have Delirium and hold Delusions simultaneously.
Is it easy to convince someone out of their Delusion?
Typically, individuals with Delusions firmly hold onto their beliefs, making it challenging.
Can Delirium be a symptom of an underlying medical condition?
Yes, Delirium can result from infections, surgery, or other medical conditions.
How long does Delirium usually last?
Delirium is usually temporary, but its duration can vary based on the underlying cause.
How do professionals treat Delusions?
Treatment for Delusions often involves therapy, medication, or a combination of both.
Are hallucinations a part of Delirium?
Yes, individuals in Delirium can experience hallucinations.
Is Delusion always negative?
Delusions can be neutral, but they are often distressing or impairing to the individual.
Are there different types of Delusions?
Yes, Delusions can be of grandeur, persecution, reference, and more.
Is age a factor in Delirium?
Yes, older adults are more susceptible to Delirium.
Can a Delusion ever be true?
By definition, a Delusion is a belief contrary to evidence, so it's not based on fact.
Can Delirium and Delusion symptoms overlap?
Yes, both can involve altered perceptions of reality, but their core definitions differ.
Can sleep deprivation cause Delirium?
Yes, extreme sleep deprivation can contribute to Delirium.
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Written by
Fiza RafiqueFiza Rafique is a skilled content writer at AskDifference.com, where she meticulously refines and enhances written pieces. Drawing from her vast editorial expertise, Fiza ensures clarity, accuracy, and precision in every article. Passionate about language, she continually seeks to elevate the quality of content for readers worldwide.
Edited by
Tayyaba RehmanTayyaba Rehman is a distinguished writer, currently serving as a primary contributor to askdifference.com. As a researcher in semantics and etymology, Tayyaba's passion for the complexity of languages and their distinctions has found a perfect home on the platform. Tayyaba delves into the intricacies of language, distinguishing between commonly confused words and phrases, thereby providing clarity for readers worldwide.
