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Sundowning or sundown syndrome,[1] is a neurological phenomenon associated with increased confusion and restlessness in patients with delirium or some form of dementia. Most commonly associated with Alzheimer's disease, but also found in those with other forms of dementia, the term "sundowning" was coined due to the timing of the patient's confusion. It's also known as “late-day confusion". The term "sundowning" refers to a state of confusion occurring in the late afternoon and spanning into the night. It can cause a variety of behaviors, such as confusion, anxiety, aggression or ignoring directions. Also, it can lead to pacing or wandering. For patients with sundowning syndrome, a multitude of behavioral problems begin to occur in the evening or while the sun is setting.[2][3][4]

Causes of sundowning

The specific causes of sundowning have not been empirically proven, some evidence suggests that circadian rhythm disruption increases sundowning behaviors. In humans, sunset triggers a biochemical cascade that involves a reduction of dopamine levels and a shift towards melatonin production as the body prepares for sleep. In individuals with dementia, melatonin production may be decreased,[1] which may interrupt other neurotransmitter systems. It is thought that with the development of plaques and tangles associated with Alzheimer's disease there might be a disruption within the suprachiasmatic nucleus (SCN).[4] The suprachiasmatic nucleus is associated with regulating sleep patterns by maintaining circadian rhythms, which are strongly associated with external light and dark cues. A disruption within the suprachiasmatic nucleus would seem to be an area that could cause the types of confusion that are seen in sundowning. However, finding evidence for this is difficult, as an autopsy is needed to definitively diagnose Alzheimer's in a patient. Once an Alzheimer's patient has died, they have usually surpassed the level of dementia and brain damage that would be associated with sundowning. This hypothesis is, however, supported by the effectiveness of melatonin, a natural hormone, to decrease behavioral symptoms associated with sundowning.

Other possible causes of sundowning include: fatigue, unmet needs such as hunger or thirst, depression, pain, boredom, low lighting ,increased shadow, difficulty separating reality from dreams, presence of an infection such as urinary tract infection

Symptoms of sundowning

Symptoms are not limited to but may include:

  • Increased general confusion as natural light begins to fade and increased shadows appear.[2][5]
  • Agitation and mood swings.[2][3]
  • Mental and physical fatigue increase with the setting of the sun.[2][3]
  • Tremors may increase and become uncontrollable.
  • An individual may experience an increase in their restlessness while trying to sleep. Restlessness can often lead to pacing and or wandering which can be potentially harmful for an individual in a confused state.[3]

Treatment of sundowning

  • If possible, a consistent sleeping schedule and daily routine that the patient is comfortable with can reduce confusion and agitation.[2]
  • If the patient's condition permits, having increased daily activity incorporated into their schedule can help promote an earlier bed time and need for sleep.[2][3]
  • Check for over-napping. Patients may wish to take naps during the day, but unintentionally getting too much sleep will affect nighttime sleep. Physical activity is a treatment for Alzheimer's, and a way to encourage night sleep.[3]
  • Caffeine is a (fast-working) brain stimulant, but should be limited at night if a night's sleep is needed.[2][3]
  • Caregivers could try letting patients choose their own sleeping arrangements each night, wherever they feel most comfortable sleeping, as well as allow for a dim light to occupy room to alleviate confusion associated with an unfamiliar place.[3]
  • In the evening, try to reduce background noise and stimulating activities, including TV viewing, which can sometimes be upsetting.
  • In a strange or unfamiliar setting, bring familiar items — such as photographs — to create a more relaxed, familiar setting.
  • Play familiar gentle music in the evening or relaxing sounds of nature, such as the sound of waves.
  • Some evidence supports the use of melatonin to induce sleep.[4] Some research suggests that a low dose of melatonin — a naturally occurring hormone that induces sleepiness — alone or in combination with exposure to bright light during the day may help ease sundowning


  1. [1]
  2. [2]


  1. 1.0 1.1 Khachiyants N, Trinkle D, Son S, Kim K. Sundown syndrome in persons with dementia: an update. Psychiatry investig, 2011; 8:275-87
  2. 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Smith G. Sundowning: Late-day confusion. 2011
  3. 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 Alzheimer's Association: Sleepelessness and Sundowning
  4. 4.0 4.1 4.2 de Jonghe A, Korevaar J, Munster B. Effectiveness of Melatonin treatment on circadian rhythm disturbances in dementia: Are there implications for delirium? A systematic Review. International Journal of Geriatric Psychiatry. 2010;25(12):1201-18
  5. Keller S. Sundwoning WedMD LLC, 2012