Difference Between Dementia and Delirium

Main Difference – Dementia vs Delirium

Dementia and Delirium are two major psychiatric conditions, which generally manifest with similar symptoms and signs are different from each other only in very few aspects. However, it is important to know the facts which differentiate one from the other for the purpose of treatment and supportive measures since both these conditions becoming common in the modern society. The main difference between dementia and delirium is that dementia is irreversible and gradually develops over time whereas delirium is irreversible.Difference Between Dementia and Delirium - infographic (1)

What is Dementia

Dementia is the progressive and irreversible declining of brain function which occurs as a result of certain conditions such as Alzheimer’s disease, Parkinson’s disease, Multiple sclerosis, stroke and various medications. Demented patients will have problems with memory, language, speaking attention, cognition and emotions which usually get worse gradually over time.

They will initially show forgetfulness and confusion which will gradually impair the performance in day to day activities. They may also be disoriented, moody, and restless with issues in talking with others and expressing themselves.  

The modes of treatments for both Dementia are based on the underlying causes;  the symptoms of a patient with dementia can often get improved by relaxation techniques and mental exercises.

Main Difference - Dementia vs Delirium

What is Delirium

Delirium is usually referred to an acute stage of confusion which is commonly mistaken as Dementia, depression, or a part of the aging process. Being a condition which is diagnosed clinically, the main features of Delirium include the acute onset of fluctuating course, poor attention span, inattention, distraction, impaired rational thinking ability and altered level of consciousness which might be associated with hallucinations and delusions.

Renal and liver failure, brain tumors, trauma to the head, dehydration (electrolyte imbalance) and infections such as urinary tract infections and pneumonia are known to be the commonest causes which can result in Delirium. Additionally, various poisons, alcohol, and drug abuse can result in acute delirium where patients will have altered levels of alertness, personality changes like agitation and anxiety, rambling speech, impaired short term memory, slow or hyperactive movements and disturbances in sleep.

It is highly necessary to identify the clinical features which are unique to each condition. Delirium is considered as a medical emergency which can even result in death without proper and quick medical interventions.

Difference Between Dementia and Delirium

Difference Between Dementia and Delirium


Dementia: Dementia is a  chronic or persistent disorder of the mental processes caused by brain disease or injury and marked by memory disorders, personality changes, and impaired reasoning.

Delirium: Delirium is an acutely disturbed state of mind characterized by restlessness, illusions, and incoherence, occurring in intoxication, fever, and other diseases. 


Dementia: Dementia is an irreversible disorder which develops gradually over time until it reaches the maximum severity

Delirium: Delirium is reversible and can be cured with timely diagnosis and interventions.


Dementia: Delirium patients seem to be quiet, sleepy and relaxed at times with sudden phases of agitation and restless

Delirium: Patients with dementia will often stay confused about people, things, and time.

Image Courtesy:

“Alzheimer’s disease brain comparison” by derivative work: Garrondo (talk)SEVERESLICE_HIGH.JPG: ADEAR: “Alzheimer’s Disease Education and Referral Center, a service of the National Institute on Aging.”PRECLINICALSLICE_HIGH.JPG: ADEAR: “Alzheimer’s Disease Education and Referral Center, a service of the National Institute on Aging.” – SEVERESLICE_HIGH.JPGPRECLINICALSLICE_HIGH.JPG, (Public Domain) via Commons Wikimedia 

“Delirium” by Erich Ferdinand (CC-BY-2.0) via Flickr

About the Author: Embogama

Embogama is a passionate freelance writer for several years. Her areas of interest include general medicine, clinical medicine, health and fitness, Ayurveda medicine, psychology, counseling and piano music