Sundowning, sometimes called “sundowner’s syndrome,” is a pattern of increased confusion, agitation, and anxiety that emerges in the late afternoon or evening in people with dementia or Alzheimer’s disease. It’s not a formal psychiatric diagnosis but a clinical term describing a recognizable cluster of behavioral changes tied to the time of day. Roughly 1 in 5 people with dementia experience it.
What Sundowning Looks Like
The hallmark of sundowning is its timing. A person who seemed relatively calm and oriented during the morning may become noticeably different as the sun goes down. The shift can include confusion, disorientation, irritability, restlessness, pacing, wandering, and resistance to requests. Some people rock in a chair, cry, or yell. Others “shadow” their caregiver, following them from room to room.
Emotional changes are just as common as behavioral ones. Fear, sadness, anxiety, and agitation can appear suddenly or build over the course of the evening. In more severe cases, sundowning involves paranoia, suspiciousness, delusions, or visual and auditory hallucinations. Mood swings and an abnormally demanding attitude are also typical. The combination of symptoms varies from person to person and can even vary night to night, which makes it especially difficult for caregivers to predict or prepare for.
Why It Happens in the Evening
The brain has an internal clock, located in a tiny region called the suprachiasmatic nucleus, that regulates sleep-wake cycles and other daily rhythms. In Alzheimer’s disease and other forms of dementia, the nerve cells that help this clock function properly degenerate. When those cells are damaged, the brain loses its ability to distinguish between “time to be awake and alert” and “time to wind down for sleep.” The result is a kind of neurological collision: the brain tries to process stimulation at a moment when it’s already shifting into a sleep-ready state.
Hormones play a role too. Melatonin, the hormone your body releases in response to darkness to promote sleep, declines with normal aging but drops even further in people with Alzheimer’s and other neurodegenerative diseases. At the same time, cortisol, a stress hormone, tends to be significantly higher in dementia patients who experience sundowning compared to those who don’t. So the biological setup is a person whose sleep signals are weak and whose stress signals are elevated, right at the time of day when the environment is getting darker and more disorienting.
Common Triggers
While the underlying cause is neurological, certain everyday factors can make episodes worse or more likely. Physical exhaustion from a full day of activity is a major one. So is overstimulation, such as a noisy household in the evening, visitors, or a television playing in the background. Dim lighting or shadows can increase confusion and contribute to visual misperceptions. Hunger, thirst, pain, and unmet bathroom needs can all trigger agitation in someone who may not be able to communicate what’s wrong.
Changes in routine are particularly destabilizing. A new caregiver, a different mealtime, an unfamiliar room, or even seasonal shifts in daylight can be enough to worsen symptoms. Caffeine and sugar consumed later in the day can also interfere with the already-disrupted sleep-wake cycle.
How Sundowning Differs From Delirium
Because sundowning involves sudden confusion and sometimes hallucinations, it can look a lot like delirium, which is a medical emergency caused by infections, medication reactions, or other acute problems. The key differences matter. Delirium comes on suddenly over hours or days and involves a noticeably altered level of consciousness: the person may seem drowsy, unable to focus, or dramatically “not themselves” in a way that goes beyond their usual dementia symptoms. Sundowning, by contrast, follows a predictable daily pattern and doesn’t involve a change in consciousness level.
Delirium is also reversible once the underlying cause is treated, while sundowning is an ongoing feature of the dementia itself. If a person with dementia suddenly becomes much more confused than usual, especially during the daytime or without the typical evening pattern, that warrants urgent medical attention to rule out delirium from an infection, medication issue, or other treatable cause.
Managing Sundowning at Home
There’s no single fix, but a combination of environmental and routine adjustments can reduce how often and how severely episodes occur. The most effective strategies focus on stabilizing the person’s daily rhythm and reducing confusion during vulnerable hours.
- Keep a predictable schedule. Consistent times for waking, meals, activities, and bedtime help reinforce the body’s weakened internal clock.
- Maximize daytime light exposure. Spending time in bright light during the day supports nighttime sleepiness. Bright light therapy using lights at 2,500 lux for about two hours, either in the morning or late afternoon, has been shown to help regulate circadian rhythms in dementia patients.
- Limit daytime napping. Long or late naps can make nighttime confusion worse.
- Reduce evening stimulation. Turn off the TV, lower background noise, and keep the environment calm as the afternoon progresses.
- Keep rooms well-lit in the evening. Turning on lights before sunset, rather than letting the house gradually darken, can reduce disorientation and the visual confusion that shadows create.
- Move caffeine and sugar to morning hours only. Both can interfere with an already fragile sleep cycle.
Simple physical comfort checks are also important. Pain, constipation, a full bladder, or being too warm or cold can all amplify agitation in someone who can’t easily say what’s bothering them. Addressing these basics before the evening hours can prevent some episodes entirely.
The Role of Light Therapy
Because sundowning is rooted in circadian rhythm disruption, bright light therapy is one of the more studied approaches. The idea is straightforward: exposing the brain to intense light at specific times of day helps recalibrate the internal clock. Studies have used light boxes delivering 2,000 to 2,500 lux for two-hour sessions, typically in the morning (around 9:30 to 11:30 a.m.) or the late afternoon and evening. Morning light exposure has shown the most consistent effects, including measurable shifts in the body’s activity rhythm within two weeks. Evening light has also shown benefits for sleep quality, though results have been more variable.
Light therapy isn’t a cure, but it can meaningfully reduce sleep disruption and some of the behavioral symptoms that go along with it. It’s also low-risk, which makes it a practical option for caregivers looking for non-drug approaches.
What Caregivers Should Know
Sundowning is one of the most exhausting aspects of caring for someone with dementia because it strikes at the end of the day, when the caregiver is also tired. It’s worth knowing that the person experiencing sundowning isn’t being deliberately difficult. Their brain is genuinely struggling to process the world around them at that moment, and the fear and confusion they feel are real to them.
Arguing, correcting, or trying to reason with someone mid-episode rarely helps and often makes things worse. A calm voice, gentle redirection, and a familiar activity like folding towels or listening to music they enjoy tend to be more effective. When shadowing behavior happens, it usually reflects a deep sense of insecurity, and allowing the person to stay close rather than insisting on independence can ease their distress.
Melatonin supplements are sometimes used to address the hormonal shortfall that contributes to sundowning, based on the finding that melatonin levels are abnormally low in people with Alzheimer’s. This is worth discussing with the person’s healthcare provider, particularly if sleep disruption is a major part of the picture.