The Link Between the ICU and Dementia

Medically Reviewed by Christopher Melinosky on December 16, 2020

ICU delirium is severe confusion that can happen to people while they’re in a hospital’s intensive care unit (ICU). There are several possible reasons for it, and it can lead to serious and possibly long-lasting brain problems, including dementia.

The ICU and Your Brain

The ICU is for people who need round-the-clock care. If you’ve had a life-threatening illness or injury and need major surgery, you’re likely to be there for the first part of your recovery.

People in intensive care are often given powerful drugs. They may also have conditions that affect their brain chemistry or how much oxygen reaches their brain. These things can affect how your brain handles information or balances your mood. They can throw off how you think, communicate, and see the world around you. That’s called delirium, or being delirious.

When you’re delirious, you might not know where you are, or you might think you’re somewhere other than the hospital. You might see or hear things that aren’t there, and you may not be able to speak clearly to other people who want to help. It’s been described as being in a bad dream -- one that can be scary for those around you, too.


Other common signs of delirium are:

  • Confusion about what day it is
  • A hard time concentrating
  • Being unable to remember things
  • Sudden changes in mood

If you’re delirious, you also might think you’re in danger and need to leave the hospital, or you may try to remove tubes or catheters.

Long-Term Effects

Delirium is temporary, but it can take days or weeks for it to go away completely. And research shows that it may lead to problems even after you leave the hospital. More than a third of people who recover from a serious illness in the ICU have trouble thinking clearly, remembering or organizing things, or solving problems afterward.

This can get better in time, but that’s not the case for everyone. Some studies show that up to 75% of people who get out of intensive care show some signs of dementia -- a permanent loss of certain mental abilities, like memory and communication.

Scientists aren’t sure why, but your chances of this seem higher the longer you’re given medicine to make you sleep. People with serious conditions like sepsis, kidney failure, or brain disorders or have had heart surgery also seem to have higher odds of dementia afterward.

Prevention and Treatment

Because of the connection between ICU delirium and long-term problems, doctors have come up with checklists to prevent issues or cut them short if they start. These steps include:

  • Looking for signs of pain or discomfort in people who can’t talk
  • Using painkillers that may be less likely to trigger delirium
  • Letting people get better rest without being disturbed often
  • Taking people off of breathing machines sooner
  • Getting people up and moving earlier
  • Involving family members in their care
WebMD Medical Reference



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ICUsteps: “Delirium and Intensive Care.”

Dimensions of Critical Care Nursing: “Delirium and Dementia in the Intensive Care Unit.”

National Institute on Aging: “What is Dementia?”

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The New England Journal of Medicine: “Cognitive Trajectories after Postoperative Delirium.”

Journal of the American Medical Association: “Delirium as a Predictor of Mortality in Mechanically Ventilated Patients in the Intensive Care Unit.”

Critical Care Nurse: “Delirium in the Intensive Care Unit: Medications as Risk Factors.”

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