Difference Between Delirium and Dementia


Delirium and dementia are often confused with one another by a variety of well meaning observers. However, the two mental disorders could not be more different from each other. In order to understand the differences between delirium and dementia, it is important to grasp the complexities of each mental disorder.


Delirium is when a person’s mental state undergoes a rapid and dramatic shift. Delirium is not a static condition, it is one that undergoes shifts by the week, the day, or even the hour. A person who is suffering from delirium will usually find it difficult to focus on their usual daily tasks.

Memories and emotions are affected, as well as the ability to think clearly and pay attention. Delirium is a very common mental disorder, one that can be treated if the person is willing to seek the appropriate medical attention. Due to the fact that untreated delirium can cause further mental issues and even death, it is usually treated as a serious medical emergency.


Dementia, on the other hand, is not a specific disorder and is a term used to describe the varied signs of a person’s diminishing brain function. Dementia takes place over the course of time and slowly erodes the person’s ability to communicate effectively with the people around them, remember key facts about their day to day existence and formulate coherent thoughts.

It can be challenging to properly diagnose dementia during the early stages, as it can easily be confused with normal forgetful behavior or attributed to the natural aging process. Confusion is another typical early symptom that is often explained away by observers and ignoring either of these warning signs could have severe consequences over the long haul.

Simple tasks begin to elude those who are suffering from the onset of dementia. Even something as normal as following directions or completing daily tasks that they have become accustomed to handling with ease becomes extremely problematic. Talking to people and having a firm grasp on what they are saying also takes on an added level of difficulty. Forgetting who they are, who the people around them are and increased feelings of moodiness or restlessness are other common dementia symptoms.

What Are the Differences?

So how are these two seemingly similar mental ailments different from one another? While they do share a number of similarities as it relates to the onset or the symptoms, they are caused by different factors, treated in various manners and each possesses a wide range of outcomes.

First and foremost, dementia is not a condition that sets in overnight, it takes place over the course of time, whereas delirium can happen immediately. A person who is experiencing any form of delirium should seek medical treatment right away, while dementia can take years to reach its peak level.

Delirium is often mistaken for dementia and the two disorders can even take place at the exact same time. Dementia sufferers tend to experience confusion and often forget key facts about themselves or the people they are closest to. Delirium is more difficult to diagnose, because the person is usually sleepy, restless and distressed, all symptoms that could be attributed to other ailments.

While a person who is suffering from delirium may become too quiet, which serves a warning sign, a dementia sufferer will continue to remain talkative. However, their speech becomes impeded and it may become challenging for them to express a complete though, which causes extreme frustration.

Dementia is marked by a slow, gradual decline in the person’s ability to formulate thoughts and communicate them effectively. Their mental state and their daily behaviors change over the course of several years, in most instances.

Delirium can strike when a person least expects it. Their mental state will change suddenly, without any warning whatsoever. Within mere hours or days, a person who has functioning normally can become stricken with delirium.

Should a person show signs of either mental disorder, they should submit themselves to the care of a medical professional, so that they can receive a rapid diagnosis. Both disorders will require a person who is already familiar with the person’s usual medical state to speak with the doctor, so that the physician can differentiate their current state from what is normal behavior for the patient.

Depending on the condition, a health care provider will take a look at a variety of health aspects in order to determine a cause. Prescribed medications can often be a catalyst, especially in cases of delirium. Medications can have a drastic impact on the brain function of an adult and a doctor will thoroughly investigate.

Infections and illnesses can also cause these mental disorders to take place. While dementia happens slowly and can typically be attributed to the natural aging process, delirium is usually triggered by a new medication or a life event. In many cases, the health care provider performs a series of tests to see if they can identify the patient’s delirium trigger.

Since both of these disorders are very similar and can take place at the same time, it is important for a family member or caretaker to seek immediate medical attention should a person show signs of either disorder. Sudden changes in a mental state usually indicate the onset of dementia, while a gradual decline in the ability to think and communicate is normally a sign of dementia. Be sure to tell the health care provider about all of the symptoms, so that they can make a measured judgement on options for treatment.