Alzheimer’s Disease and Delirium

WebMD Medical Reference in Collaboration with the Cecil G. Sheps Center at the University of North Carolina at Chapel HillLogo for UNC Chapel Hill, Cecil G. Sheps Center
Medically Reviewed by Christopher Melinosky, MD on November 27, 2022
6 min read

It’s normal for people with Alzheimer’s disease to feel more confused as time passes. But sometimes this confusion gets worse very quickly, over a matter of hours or days. If this happens with your loved one, take them to a doctor as soon as possible to be sure that it’s not delirium.

You should also get medical help as soon as possible if they seem more confused than usual and have a fever. This is when the temperature measured under the tongue is 99 F or higher, or is 1.2 degrees higher than their normal body temperature.

It’s when confusion gets worse suddenly and comes and goes over several hours or days. It happens when a new health problem puts too much stress on the brain, and it can be a sign of a serious illness.

Your loved one may have delirium if they:

  • Are more easily distracted than usual
  • Find it harder than usual to remember things
  • Talk about something totally different, or are harder to understand than usual
  • Are more or less energetic than is normal for them
  • See things that aren’t there
  • Show unusual emotions, such as fear or depression
  • Have a change in personality that comes on in a few hours or days
  • Have changes in behavior that quickly switch between alertness and confusion or sleepiness

Each of these signs on its own can be caused by other problems, but when they happen together, it’s likely delirium.

In older people who have dementia, delirium is usually caused by medications, anesthesia and drugs for pain after surgery, and medical conditions like infections or long-term diseases that get worse.

Sundowning describes how some people with dementia have more issues with agitation, anxiety, or confusion during the late afternoon or evening. The main difference between this and delirium is that delirium happens suddenly and comes and goes throughout the day.

If your loved one is sundowning for the first time, call their doctor to make sure it’s not delirium.

Doctors don’t fully understand why sundowning happens, but it could be related to exhaustion, less light, or an issue with the “internal body clock.”

Treatment usually involves things you can try at home, such as turning on more lights, planning more daily activities, and helping your loved one get plenty of rest.

Since delirium is usually caused by a health problem, it’s important to talk with your loved one’s doctor about finding the reason for it and to follow any treatment instructions.

You also can do a few things to help manage delirium:

  • Talk to your loved one calmly. Make eye contact. If they’ll let you, use a gentle touch.
  • Give simple, clear instructions.
  • Tell them often what day it is, what time it is, where they are, and who the people around them are. If they’ve had Alzheimer’s disease for a while, reminders may not help. If your loved one seems upset by them, try to just go along with whatever they say or believe.
  • When you do things to take care of them, remind them who you are and tell them what you’re about to do.
  • Help them remember the time, date, where they are, and what they’re doing. It helps to use something they can see, like a clock or watch, calendar, or daily schedule.
  • Keep the area around them familiar and calm. Lower loud, distracting noises, such as phones or loud TVs, but don’t have complete silence. You may want to softly play their person’s favorite music or TV show.
  • Put on soft lighting. Try a 40- to 60-watt night light.
  • Try to keep your home’s temperature between 70 and 75 F. Stay away from very high or low temperatures, inside or outside.
  • Have family and other familiar people spend time with them, but don’t have too many visitors at once.
  • Try to stick to a structured routine.
  • Make sure your loved one drinks enough fluids.
  • Encourage them to get up and walk around. Provide help if needed.
  • If they need glasses, a hearing aid, or dentures, try to make sure they wear them. Check that their glasses are clean and the right ones for the distance. Make sure their hearing aid works and is turned on.

If a doctor has told you your loved one doesn’t have delirium but is sundowning, try these things:

  • Keep the home well-lit in the evening.
  • Offer healthy food and drink later in the day. If you give them sweets and caffeine, do this in the morning. Try to have a large meal at lunch and keep the evening meal simple.
  • Help them avoid nicotine and alcohol as much as possible.
  • Plan activities in the early part of the day, and try not to let them nap in the afternoon. This will help them be relaxed later. Help them get regular exercise such as walking in the early part of the day.
  • Pay attention to how tired you feel. If you’re stressed by late afternoon, they may pick up on it and get agitated or confused in response.
  • Try to figure out what is causing the increased confusion, anxiety, or agitation during the evening, and then make a plan to stay away from or stop these things. For example, if you think loud TV shows or too much activity could be the cause, try to cut down on these activities at night.
  • Make a comfortable and safe area to sleep. Make sure the bedroom is at a comfortable temperature.
  • Turn loud, distracting noises such as phones, stereos, or TVs down or off.



  • Agitation: If someone has delirium, they might be irritable, anxious, or restless. Check to see if they’re wet, constipated, have a bowel movement in their clothes, are in pain, or are hungry, thirsty, or tired. If they’re agitated, they may hit, push, scream, or have other aggressive behaviors.
  • Falls: Delirium can make them more likely to fall.
  • Wandering: Confusion can lead someone to wander off. This can be dangerous, especially if they get lost in an area with cold winters, busy roads, swimming pools, or rivers.
  • Not getting enough water (dehydration): This can become a problem for people with delirium.


You can do some things to help make it less likely that your loved one will have delirium:

  • Help them stay as healthy as possible and have good eating and sleeping habits.
  • Remind them to drink plenty of fluids, and help them get exercise every day.
  • Make sure they have their eyesight and hearing checked regularly.
  • Try to stay away from medications, especially ones that can cause sleepiness or confusion, such as tranquilizers, narcotic pain medications, and sleeping pills. If medication has to be used, such as for pain, ask a doctor about using short-acting ones in lower doses.
  • If your loved one’s in a new place, such as a hospital, have someone who knows them stay with them at all times.


It’s normal to feel scared or overwhelmed when you care for someone with delirium. Even things you do to help can upset them. It can also cause them to do things that are unsafe for you and them.

It can be hard to know if or when delirium may cause someone to get aggressive. To keep your loved one from hurting themselves or others, take away or lock up anything in the home that could be used as a weapon. If they get physically violent, stop what you’re doing and back away. Call for help if you need to.

Remember that delirium may cause a person to say or do things that are rude or hurtful, but it’s not something they can control.