About Delirium

What is delirium?

Delirium is a sudden change in mental status, or sudden confusion, which develops over hours to days. It is different from dementia, such as Alzheimer’s disease, which is a condition that develops over many months and years. Any suspected sudden change in mental status should be reported to a medical professional right away.

What does delirium look like?

Delirium causes a person’s mind to become clouded and makes paying attention or focusing thoughts difficult.  The following are some distressing symptoms that may occur when a loved one experiences delirium:

  • Difficulty understanding what is happening around them
  • Saying things that do not make sense (incoherence)
  • Seeing or hearing things that are not really there (visual and/or auditory hallucinations)
  • Feeling fearful that people are trying to harm them 

These symptoms tend to come and go during the course of the day. Confusion regarding day-to-day events, daily routines, and who certain people, or even family members, are is common. Changes in personality can occur. Some persons become quiet and withdrawn while others become stressed, anxious, or "hyper." Delirium may also cause someone to be awake all night and sleep during the day.  It may also cause a disruption in their eating habits.  During a delirious episode, some patients do not feel hungry and forget to eat and drink, so caregiver support is important during this time.

Potential Causes

Delirium is an especially common and serious problem in hospitalized older patients and requires immediate medical treatment. Delirium can slow the healing or recovery process, leading to more time spent in the hospital.  There are some common causes of delirium that have been identified, such as infections, dehydration, side effects of certain medications, or the effect of drugs in the body along with other medical conditions.  It is important to report a suspected delirious episode so that a medical professional can find out the cause and begin treatment.  The sooner delirium is identified, the faster it can be treated.  With quick treatment, delirium may clear within a few days.


This brochure is a guide to delirium for patients, family members, and caregivers and provides information on topics such as delirium symptoms, tips for reducing the risk of delirium, and caring for a loved one who is delirious.