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Delirium: The Most Common Health Complication You've Never Heard Of

For older adults, it can hit hard during routine hospital stays

doctor leans over and talks to a patient in a hospital bed


En español | About half of adults 65 and older who are admitted to the hospital find themselves in an unforeseen state of confusion during their stay. Sometimes the change is mild and temporary; other times the effects are more severe and can have a lasting impact on brain health.

It's called delirium, and according to a new report from the AARP-founded Global Council on Brain Health (GCBH), it's “the most common surgical complication for older adults you likely have never even heard of.” In fact, a recent AARP survey on delirium and brain health of adults 50 and older found that 74 percent of respondents were not familiar with the condition.

A frequent and frightening reality

Simply put, delirium is a sudden change in thinking and behavior that is often brought on after an injury, illness, infection or surgery — although “it can be triggered by almost anything,” explains geriatrician Sharon Inouye, a professor of medicine at Harvard Medical School and director of the Aging Brain Center at the Hinda and Arthur Marcus Institute for Aging Research, Hebrew SeniorLife, in Boston.

And it can show up in many different ways, which makes delirium difficult to diagnose. A patient, for example, may appear drowsy or “just not themselves” during a hospital stay. They may not know “where they are; they may think they're at home,” says Inouye, a contributor to the GCBH report. “They may not recognize people — even familiar people, even family members. They may not remember the nurse who was just in their room 10 minutes ago.”

Restlessness, agitation, paranoia and hallucinations are other common signs of delirium. But no matter how it manifests, delirium can be traumatic for the more than 6 million Americans 65 and older who experience it each year.

"When we interview patients right after an experience of delirium and ask them what they remember, they report being extremely frightened — often being angry, not being able to communicate, not being able to understand what was going around them,” Inouye notes.

A 2020 AARP survey found that among adults who had personally experienced delirium, 44 percent said they were frightened by the experience, with 19 percent saying they were very or extremely frightened.

What's also scary is the lasting damage delirium can cause. While most recover from its sudden symptoms — which can last hours or continue on for months — some people never return to their previous level of functioning, according to the GCBH report. People who experience delirium may later find they have difficulty carrying out everyday activities. They also may be more likely to experience falls or notice longer-term declines in thinking and memory, the GCBH report states.

Preventing delirium is possible

There is some good news when it comes to delirium, however: Oftentimes, “people can make a difference in what happens to them,” explains Marilyn Albert, director of the Division of Cognitive Neuroscience in the Department of Neurology at the Johns Hopkins University School of Medicine and chair of the GCBH.

According to the GCBH report, delirium is preventable in up to 40 percent of cases.

Delirium can be traumatic for the more than 6 million Americans 65 and older who experience it each year.

Before a planned trip to the hospital, patients can build up their physical and mental resilience by way of exercise, diet and adequate sleep. Experts often refer to this practice as “prehabilitation.” The GCBH report also recommends patients bring a list of all the medications they are taking to the hospital, along with their hearing aids, prescription glasses and dentures to help keep them oriented.

Finally, ask for a delirium screening, says GCBH Executive Director Sarah Lenz Lock.

"Once you're delirious, you are kind of at the mercy of everything,” Lock says, which is why she recommends inquiring about a screening before any procedure or hospital admission.

"If everybody who is 50 and older went into elective surgery, and they didn't let their health care provider get away with not screening them, I think we could change things dramatically,” Lock says.

If an individual is identified as being at high risk for delirium ahead of a hospital stay, health care workers may be able to monitor the patient more closely and pick up any early warning signs before delirium sets in.

A patient's mental status “is a vital sign,” Inouye says. “We need to make sure your brain is working, just as we trust that your body's working fine.”

Caregivers can also play a role in keeping delirium at bay by reporting any change in mental status or behavior to health care providers and by questioning any drugs used to treat delirium — especially antipsychotic medications.

"Those kinds of things [can] help divert people from ever getting to this situation,” Lock says.

Though delirium is still an under-recognized issue for most people, experts agree it's becoming a bigger focus among medical professionals. GCBH chair Albert says, “There's more consensus on what the problem is, and there's more consensus on what might be done to reduce the likelihood of delirium as well as to make a difference once that appears.”

You can find the full report on delirium from the GCBH here. AARP also has tips for patients and caregivers on how to prevent delirium and recognize its signs.