Sundowning in dementia Why late-day confusion happens and what to change first

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Sundowning is increased confusion, restlessness, and agitation in dementia that appears or worsens in the late afternoon and early evening. Both the Alzheimer's Association and the National Institute on Aging list a steady daily schedule and daytime sunlight.

The behaviors families describe are the ones both organizations list: pacing, disorientation, anxiety and agitation, and difficulty sleeping. One more is asking to go home while sitting at home, which the Alzheimer's Association lists among the signs a person may be at risk of wandering. The timing is what makes families call it sundowning, and timing is the only thing either organization uses to define the term.

Two national organizations publish specific guidance for families in this situation, and a 2025 research review sets out what the evidence can and cannot support. This article works from their pages and says where they disagree.

Sundowning is a set of symptoms with no formal definition

The Alzheimer's Association's page Sleep Issues and Sundowning opens by calling sundowning "increased confusion that people living with Alzheimer's and dementia may experience from dusk through night." It goes on: "Also called 'sundowner's syndrome,' it is not a disease but a set of symptoms or dementia-related behaviors that may include difficulty sleeping, anxiety, agitation, hallucinations, pacing and disorientation." On cause, the page is careful. "Although the exact cause is unknown, sundowning may occur due to disease progression and changes in the brain."

The National Institute on Aging draws the line at the clock. Its page Coping With Agitation, Aggression, and Sundowning in Alzheimer's Disease, reviewed July 2024, treats agitation and aggression as the underlying behaviors and sundowning as their timing: "When these problems start to happen or worsen in the late afternoon or early evening, it's called sundowning." Elsewhere on the same page it adds a second version, "When restlessness, agitation, irritability, and confusion happen as daylight begins to fade," and one contributing factor: "Being overly tired can increase late-afternoon and early-evening restlessness."

Neither organization offers a threshold, a duration, or a test, and the gap is not theirs to close. A 2025 narrative review by Michalina Reimus and Mariusz Siemiński states the position plainly. Their paper, Sundowning Syndrome in Dementia: Mechanisms, Diagnosis, and Treatment, appeared in the Journal of Clinical Medicine. Their sentence: "the name of this syndrome is not found in international classifications of diseases, and no scientific society has developed diagnostic criteria or procedural standards for this syndrome."

Is this sundowning, or is something else wrong?

The question worth asking before any routine gets rearranged is whether the clock is the whole story, and the NIA answers it first on its own page, ahead of any coping tips. "Most of the time, agitation and aggression happen for a reason. When they happen, try to find the cause, then talk with a health care provider about possible solutions."

The causes the NIA lists are ordinary and physical. They start with pain, depression, or stress; too little rest or sleep; and constipation. Next come a sudden change in a well-known place, routine, or person, and a feeling of loss, such as missing the freedom to drive. Then too much noise or confusion, or too many people in the room, and being pushed by others to do something that Alzheimer's has made very hard or impossible. The last two are feeling lonely and not having enough contact with other people, and certain medications or interactions between two medications. The NIA notes that a doctor can give a medical exam to look for physical problems that may cause agitation and aggression.

Constipation and pain sit on that list next to loneliness, which is worth pausing on. A family that has decided the hour of the day is the problem will change the hour of the day, and the pain goes untreated. The Alzheimer's Association makes a parallel point about sleep specifically: "Physical ailments, such as urinary tract infections or incontinence problems, restless leg syndrome or sleep apnea, can cause or worsen sleep problems." Its instruction is to discuss sleep problems with a doctor to help identify causes and possible solutions.

Sundowning, by the definitions above, is a pattern that recurs at a time of day in a person already living with dementia. Which dementia that is changes other things, and the guide to the difference between dementia and Alzheimer's sets out how the two are related and what changes for medications, prognosis and day-to-day care.

Daily routine changes both sources recommend

The two lists overlap on most points. Where they overlap, the advice is about as well supported as non-drug advice in this area gets.

A schedule the day can be hung on

The NIA's first sundowning step is two words: "Stick to a schedule." The Alzheimer's Association says the same thing at more length, advising families to "encourage a regular routine of waking up, eating meals and going to bed," and to schedule appointments, trips and bathing in the morning or early afternoon hours when the person living with dementia is more alert. The Association adds one item the NIA's list does not carry: offer a larger meal at lunch and keep the evening meal lighter.

Daylight, deliberately

The NIA's second step is to "arrange a time to go outside or sit by a window to get sunlight each day." The Association's version is "when possible, spend time outside in the sunlight during the day." Reimus and Siemiński describe a meta-analysis on light exposure and behavioral symptoms in dementia finding that a lack of solar light exposure, as well as dim light inside care homes, may provoke anxiety, agitation, delusions, and other symptoms.

The dim-light finding is where a piece of very common advice falls apart: dim the lights slowly as evening comes. It sounds right, it matches how a calm evening feels, and the Alzheimer's Association tells families the opposite. "Keep the home well lit in the evening to help reduce the person's confusion." Its reasoning is on the same page, in the list of factors that contribute to trouble sleeping: "Low lighting can increase shadows, which may cause the person to become confused by what they see. They may experience hallucinations and become more agitated." A caregiver who dims the lamps to calm the room may be adding the shadows that start the next episode. Turning the lamps back up is the change with a named source behind it.

Lower the noise, keep the light

What does come down in the evening is stimulation. The Alzheimer's Association's wording is "reduce stimulation during the evening hours. For example, avoid watching TV, doing chores or listening to loud music. These distractions may add to the person's confusion." In its guidance on agitation generally, the NIA asks families to "create a comforting home setting." That means reducing noise and clutter, playing soothing music, keeping well-loved objects and photos around the home, and letting in natural light during the day. The room stays bright and gets quieter.

Movement in the day, and a walk if it fits

"Aim to be physically active each day, but don't plan too many activities," the NIA says. The Association suggests taking a walk with the person to help reduce their restlessness. Reimus and Siemiński describe one study in which people with dementia spent 120 minutes a week walking with their caregivers; after six months, the authors report a significant improvement in the frequency and intensity of sundowning symptoms, especially among those who took their walks in the afternoon. That is a single study reported inside a narrative review, not a treatment protocol, and the review presents it as promising, well short of settled.

Sleep, naps, caffeine and alcohol

The NIA advises avoiding alcoholic drinks and beverages with caffeine, such as coffee or cola, late in the day, and discouraging long naps and dozing late in the day. The Alzheimer's Association adds nicotine to the caffeine and alcohol list, since all three can affect the ability to sleep, and asks families to limit daytime naps if the person has trouble sleeping at night. Neither source gives a cutoff hour or a nap length. A family that wants one will have to settle it with the person's doctor.

Keeping notes on what came first

One Association tip is easy to skip and costs nothing: "Make notes about what happens before sundowning events and try to identify triggers." A written record is also what a doctor can work from when a family reaches the conversation about physical causes, and it is the only way to tell whether a change made any difference.

What helps while an episode is happening

The Alzheimer's Association has a short list for when the person is awake and upset. Approach them in a calm manner. Find out if there is something they need. Gently remind them of the time. Avoid arguing. Offer reassurance that everything is all right. And one instruction stated flatly: "Don't use physical restraint. Allow the person to pace back and forth, as needed, with supervision."

"Gently remind them of the time" and "Avoid arguing" sit next to each other on that same list. The Association carries both and does not reconcile them. A reading that fits both is that a quiet statement of the hour is not the same act as arguing a person out of a belief. The Association names arguing as the thing to avoid. That is our reading of the two lines, and it is worth raising with the clinician who knows the person.

The NIA's in-the-moment advice runs alongside. Be patient and try not to show frustration. Speak calmly, listen to the person's concerns and avoid arguing, and reassure the person that they are safe and that you are there to help. Use other communication methods besides speaking, such as gentle touching, to help them calm down. The NIA also tells caregivers to protect themselves. Hide or lock up car keys and items that could be used in a harmful way, such as guns and kitchen knives. If the person becomes aggressive, stay at a safe distance until the behavior stops. "Talk to a doctor if aggressive behaviors worsen and consider medications that may help. In an emergency, call 911 and explain that your loved one has dementia."

Evening wandering changes the safety math

Wandering is common enough on its own that it deserves a plan independent of sundowning. The Alzheimer's Association states that six in ten people living with dementia will wander at least once, and that many do so repeatedly. On the same page it connects the two directly: identify the time of day the person is most likely to wander, and for those who experience sundowning, this may be starting in the early evening. Plan things to do during that window, since activities and exercise may help reduce anxiety, agitation and restlessness.

The Association's home measures start at the doors. Place deadbolts out of the line of sight, either high or low, on exterior doors, and never lock a person in at home. Cover door knobs with cloth the same color as the door, or use safety covers. Install warning bells above doors, or a monitoring device that signals when a door is opened. Two more on that list are night lights throughout the home, and a pressure-sensitive mat in front of the door or at the person's bedside. The Association is explicit that these actions cannot guarantee that a person living with dementia will not wander.

The number to have decided in advance is the one that governs a missing person. "If the person is not found within 15 minutes, call 911 to file a missing person's report. Inform the authorities that the person has dementia." The Association also advises beginning search efforts immediately, keeping a recent close-up photo of the person on hand to give to police, and noting that many individuals who wander are found within 1.5 miles of where they disappeared. Because wandering risk climbs as dementia progresses, the stage-by-stage Alzheimer's guide is worth reading alongside this one. Night-time episodes have their own routine, set out in our guide to nighttime wandering in dementia.

Medication carries specific cautions in dementia

Both organizations put drugs last. The National Institute on Aging states that "experts agree that medicines to treat these behavior problems should be used only after other non-drug strategies have been tried." The Alzheimer's Association writes that "for sleep issues primarily due to Alzheimer's disease, most experts encourage the use of non-drug measures rather than medication," and that in some cases when non-drug approaches fail, medication may be prescribed for agitation during the late afternoon and evening hours. Its instruction to families is to work with the doctor to learn the risks and benefits of medication before making a decision.

The NIA's page How Is Alzheimer's Disease Treated?, reviewed September 2023, is more specific about which drugs warrant caution: sleep aids, anti-anxiety drugs, anticonvulsants, and antipsychotics. It sets two conditions before any of them is considered, and both have to be met. A doctor has explained all the risks and side effects of the medicine. Other, safer non-drug options have not helped treat the problem. On antipsychotics, which are used for hallucinations, delusions, paranoia, agitation and aggression, the page states that "their side effects can be serious, including increased risk of death in some older people with dementia," and that these medications should only be given to people with Alzheimer's when the doctor agrees the symptoms are severe.

The NIA's cautions above are a report of what a federal health agency publishes, not advice about any particular person's medicines. No one should start, stop or change a prescription on the strength of a web page. The reason to know the cautions exist is so a family can raise them at the appointment, where the decision gets made.

Prevalence estimates run from under 2% to two thirds

A 20-45% prevalence figure for sundowning circulates widely, Wikipedia's sundowning article among the pages carrying it. It does not appear on the Alzheimer's Association's own sundowning page, which gives no percentage at all. Reimus and Siemiński give the span the literature actually supports. Their abstract says prevalence "ranges from 1.6% to 66% of patients with dementia." Their body text puts the same span at 2.5% to 66%. Individual studies they summarize land at 21.2% in an Italian sample of 184 people with Alzheimer's, 19% in a Spanish population, 14.3% among hospitalized patients in Brazil, and a pooled 48.9% in a 2022 review.

The review explains the spread itself: the discrepancies "may result from a lack of strict diagnostic criteria, differences in the studied population (e.g., patients living in community vs. population of nursing houses), and different pathomechanisms leading to dementia." With no diagnostic criteria, each research group counted a slightly different thing. What the authors will commit to is direction, not magnitude: "The prevalence of SS, regardless of differences in individual studies is high."

For a family, none of these numbers changes what to do this evening. They matter for one reason. A number presented as settled invites the conclusion that the science here is settled, and the people who study sundowning say it is not.

Keeping the routine going is the hard part

Everything above is daily practice, and the review's own summary of the evidence says as much: behavioral interventions are more efficacious than sedatives, and they require intense involvement of caregivers. The schedule holds because someone holds it, every day, including the days that person is exhausted.

Reimus and Siemiński note that sundowning is "an important reason for the placement of patients in nursing facilities." The Alzheimer's Association observes that the stress experienced by families and caregivers when a person living with dementia wanders and becomes lost is significant. Those are the stakes stated by the sources themselves, and they are a reason to bring the pattern to the treating doctor early, well before a year of managing it alone has gone by.

If the evenings are not improving on schedule, daylight, quiet and a lit room, the Alzheimer's Association's closing line on its own page is the next step: "If these suggestions do not help, discuss the situation with the person's doctor."