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A look at sundown syndrome

Duran, Jackie LMSW; Julian, Marcia K. MSN, RN

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doi: 10.1097/01.NME.0000717648.38630.cd
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Dementia is one of the world's leading mental health conditions and the prevalence only continues to grow with the aging population. By 2020, an estimated 35 million cases are expected globally. In addition to diminishing cognitive function as the disease progresses, most individuals living with dementia will also present with behavioral and psychological symptoms of dementia (BPSD) at some point throughout the course of the disease. Symptoms include, but aren't limited to, aggressiveness, delusions, wandering, and sociopathic behavior. These symptoms can play a significant role in caregiver burnout and increase the need for institutionalization of patients with dementia.

Sundown syndrome, or sundowning, is a common manifestation of BPSD characterized by increased agitation and general exacerbation of behavioral disturbances in the late afternoon or evening hours. Research indicates that sundowning is experienced by 10% to 25% of patients with dementia living in an institutional setting and 66% of patients living in the community. This concept of worsening disruptive behavior in the late hours of the day has been documented in the medical community for over 70 years; however, without consensus on a formal definition and reputable screening tools, sundowning presents a diagnostic challenge.

In this article, we discuss the impact of sundown syndrome on patients and caregivers, including associated factors, common symptoms, and management techniques.

Shifting definitions

Although widely recognized, sundown syndrome is poorly defined. In fact, there's no formal definition in the Diagnostic and Statistical Manual of Mental Disorders and there are no treatment guidelines specific to the management of sundown syndrome. Some researchers narrow the definition of sundowning to only impacting patients with dementia, whereas others argue the condition can occur for any older person regardless of cognitive impairment. Additionally, some researchers tend to identify sundowning by the worsening of a specific behavior, such as agitation, whereas others include a wide range of disturbed behaviors in their definition of sundown syndrome.

There are also differing opinions on the time of day when exacerbation of symptoms should occur to be classified as sundowning. Some definitions only include the late afternoon to early evening time frame, others include anytime throughout the night, and some refer simply to the hours of darkness. Some researchers have questioned the existence of sundowning syndrome altogether, arguing that disturbed behavior in patients with dementia may merely be perceived by caregivers as worsening during the evening hours when the caregivers themselves are more fatigued.

One concept that can be agreed on in the study of sundown syndrome is the burden this condition has on caregivers and medical systems. Sundowning is believed to be correlated with social and financial burdens caused by increased frequency of hospitalizations, extended length of stay in the hospital setting, and accelerated functional and cognitive decline in patients with dementia. Management of sundowning symptoms is linked to increased stress levels in both professional and family caregivers, leading to a rise in institutionalization of older patients with dementia. The negative impact of sundowning syndrome affects not only the caregiver but can also contribute to a decreased quality of life for the patient. For example, if the patient displays unsafe behavior, such as aggression or wandering, physical restraint may be necessary to protect the patient and caregivers.

Sundowning behaviors

It's important to note that sundowning isn't a disease, but rather a set of symptoms. Diagnosis is generally made through direct clinical observation of symptoms, and a behavioral history from family and caregivers is also helpful. When sundowning is suspected, lab testing may be ordered to rule out other potential causes for the behavioral changes. Especially in the case of acute agitation in older patients, infections and cardio/cerebrovascular disease must be eliminated as a cause for changes in behavior.

Behavioral symptoms of sundowning will differ among patients, but may include:

  • increased confusion
  • disorientation
  • agitation
  • anxiety
  • aggression
  • restlessness
  • hallucinations
  • wandering
  • yelling.

One report describes sundowning as a state of delirium in which the patient is completely disoriented, often presents with agitation and panic, and may engage in destructiveness. The American Sleep Association provides insight into some typical sundowning behavioral patterns, which can include “wandering outside of the house, turning on kitchen appliances, accidentally breaking household items, and shouting inappropriately.”

Associated factors

Currently, there's no clear physiologic cause for sundowning; however, it's believed to be multifactorial. We do know that a correlation exists between the severity of cognitive impairment and the development of sundowning symptoms. There are several theories about the cause of sundowning, ranging from physiologic to psychological to environmental. There are no data to support an increased risk of sundowning in any race or gender group. However, neurologic disorders, such as Alzheimer disease and Parkinson disease, as well as mental health disorders, such as anxiety and depression, can predispose a patient to sundown syndrome.

Several biopsychosocial factors may play a role in sundown syndrome. For example, higher levels of fatigue experienced by both the patient and caregiver in the late hours of the day, a chronic state of low energy, and exposure to chronic stress are noted as associated factors, particularly in patients with dementia in institutional settings. Additionally, in institutional settings, shift changes and lower staffing during the evening hours may lead to increased caregiver burden.

It's been hypothesized that the caregiver's stress level may inadvertently impact the patient's mood and behavior. Other factors contributing to sundowning among patients with dementia in institutional settings include inadequate amounts of structured stimulation during the day, leading to nighttime boredom and restlessness; inadequate exposure to daylight; excessive evening noise; and lack of evening routine. Some studies even recognize seasonal changes as correlating to sundowning, with a higher incidence in the winter.

Much of the available research on sundowning has been focused on the relationship between sundown syndrome and the sleep-wake cycle. Many researchers believe that the cause is related to dysfunction of the circadian rhythm, which regulates the sleep-wake cycle. In theory, circadian changes provide an explanation for the development of sundowning symptoms. Changes in circadian rhythm can happen for many reasons, such as alterations in the suprachiasmatic nucleus (SCN) located in the hypothalamus, a decrease in the amount of melatonin produced, or an impairment in cholinergic transmission.

It should also be noted that sleep disturbances increase with aging—the population most likely affected by dementia. Thirty-eight percent of older individuals experience sleep disturbances, including changes in the sleep cycle with a decrease in stage 3 and 4 sleep, which results in fragmented sleep and waking frequently. Sleep disturbances have been discovered to precede the onset of symptoms in patients with Alzheimer dementia. As the disease progresses, so does the decline in quality of sleep and circadian function.

A possible cause for changes in the circadian rhythm is degeneration of the SCN, the central biological clock of the brain, which is known to occur in patients with dementia. The formation of beta-amyloid plaques and the presence of neurofibrillary tangles associated with Alzheimer disease are thought to be a factor in SCN changes. The SCN changes could explain symptoms of sundowning, such as agitation, increased confusion, and sleep disturbances. The SCN receives input from the retina, which travels along the optic nerve and is essential to melatonin regulation. Melatonin plays an important role in maintaining the circadian rhythm and has been shown to decrease with both aging and in neurodegenerative disease. Light and dark alterations affect the timing of melatonin secretion, with the highest amounts of melatonin produced at night when light is diminished. The role of the SCN is to stimulate the pineal gland to stop producing the hormone in response to light (see Light and melatonin).

Pharmacologic treatment

As professionals in dementia care continue to gain a better understanding of sundown syndrome, best-practice guidelines remain incomplete. Research about the appropriate use of pharmacologic treatments for the management of challenging sundowning behaviors is still evolving. The effectiveness and safety of such options remain controversial.

Medications that are used to treat Alzheimer disease may indirectly improve behaviors associated with sundowning by improving patient cognition. Acetylcholinesterase inhibitors (AchEIs) and the N-methyl-D-aspartate (NMDA) antagonist memantine are the drugs most often used in the treatment of dementia. As the patient's cognition is improved, fewer disturbing behaviors are expected. Memantine works by protecting nerve cells from producing too much glutamate. AchEIs work by limiting the breakdown of acetylcholine in the brain and increasing the communication between neurons, resulting in improved cognition. It should be noted that decreased cholinergic transmission is also a factor in circadian rhythm dysfunction, so medications that have anticholinergic properties should be avoided.

There's no evidence supporting the use of benzodiazepines—another commonly used sundowning treatment. In fact, these medications have been shown to intensify disturbed behavior for patients with dementia. An alternative to benzodiazepines is trazodone, which has a sedative effect and has been used to treat insomnia and sundowning. Keep in mind that this medication can cause dizziness and lightheadedness, which can contribute to fall risk.

Figure
Figure:
Light and melatonin

Antipsychotics are perhaps the most controversial, yet most widely used, class of drug in the treatment of BPSD and sundown syndrome. Antipsychotic drugs have been linked to severe adverse reactions, and evidence of any beneficial impact on sundowning behaviors is limited. In fact, studies of antipsychotic use in dementia patients have shown that roughly 18% of patients experience relief from disturbed behavior, whereas 49% experience a worsening of disturbed behavior. Reports suggest only modest efficacy in short-term use of antipsychotics to manage aggression, accompanied by negative adverse reactions, including increased mortality. In 2005 and 2008, the US Food and Drug Administration issued black box warnings for the use of antipsychotics for older patients with dementia due to the dangerous associated risks.

Even with the evidence of adverse reactions, antipsychotic medications may still be deemed appropriate for some patients if other therapies have failed and the patient's behavior poses a safety risk to him- or herself or others. When necessary, atypical antipsychotics are preferred because they don't have the extrapyramidal adverse reactions associated with conventional antipsychotics. The selective serotonin reuptake inhibitor (SSRI) citalopram has also shown efficacy in treating mild-to-moderate agitation but carries a risk of cardiotoxicity.

Several studies have revealed that melatonin levels are lower in patients with dementia. The use of low-dose melatonin supplementation has been studied, as well as use of the melatonin receptor agonist ramelteon to stimulate the action of melatonin. Some available data have shown supplemental melatonin to be beneficial. Patients taking ramelteon were able to fall asleep easier and stayed asleep longer. However, melatonin therapy may not meet prescription regulations in all care settings.

There are no drugs that have been approved specifically for the treatment of agitation in dementia. Care needs to be exercised because this patient population is inherently frail and at risk for sedation, decreased mobility, and cardio/cerebrovascular events. In addition to the potential adverse reactions, evidence to support the benefit of pharmacologic treatment of sundowning symptoms is lacking. Therefore, pharmacologic treatment is recommended as a second-line approach (see Pharmacologic treatments for sundowning).

Nonpharmacologic treatment

The most dominant nonpharmacologic treatment option outlined in sundown syndrome research is light therapy, which is used to treat sleep disorders associated with dysfunction of the circadian rhythm. Light therapy involves exposing the patient to natural or artificial light with the goal of the additional light stimulating the SCN to reset the body's internal clock. Some studies suggest use of tools such as a light box or other dawn and dusk simulation, but recommendations are unclear as to the optimal dose or time of day during which the therapy is provided. However, it's agreed that light is the most important signal to trigger circadian rhythm, which explains why light exposure can strengthen the sleep-wake cycle of patients with dementia.

Studies show efficacy of light therapy in reducing agitation, stabilizing the circadian cycle, and increasing duration of sleep time. Light therapy may become particularly significant for patients with dementia in institutional settings because this population typically has less access to natural sunlight. Exposure to adequate sunlight is recommended for patients with dementia to help restore balance to circadian rhythm, alleviate sleep issues, and improve mood. However, the benefits of light therapy for treatment of sundowning remain unclear as research has produced mixed results.

Good sleep hygiene is an important nonpharmacologic intervention recommended as part of the care plan for patients with sundown syndrome because sleep is restorative and plays a role in cognitive function. Managing sleep disturbances is helpful to maintain daytime functioning and an inexpensive intervention that can easily be implemented by professional and informal caregivers. Patients need to be kept mentally active during the day and provided with opportunities for physical activity/exercise and social interaction. Exercise should take place early in the day. Patients with cognitive impairment benefit from following a routine in which afternoon napping is limited and the timing of going to bed and getting up each day remains consistent. Patients should be encouraged to engage in quiet activities in the evening in a calm environment that's conducive to sleep.

Table
Table:
Pharmacologic treatments for sundowning

Other interventions such as music therapy have been studied for patients with dementia and have shown some lessening of disturbed behaviors, such as anxiety and agitation. Aromatherapy with lavender oil for its sedative effect is also mentioned in the literature as a method of managing sundowning behavior.

Although additional research will be required to determine the feasibility and efficacy of nonpharmacologic methods of managing sundowning, it's widely agreed that these practices pose minimal safety concerns. Some of the research even attributes use of nonpharmacologic interventions to a decreased need for antipsychotic medications. For these reasons, nonpharmacologic approaches are recommended as the first-line treatment for BPSD.

Considerations for caregivers

Arguably as important as effective treatment options are sufficient caregiver education and support. Caring for a patient with sundown syndrome, whether in a professional capacity or as the patient's family member, can cause tremendous caregiver burden. In one study, 51% of caregivers experienced disrupted sleep as a result of the patient's sundowning symptoms. Excessive caregiver burden can lead to decreased quality of life for both patients and caregivers (see Sundowning cycle). Burnout from caring for a patient with sundown syndrome is a leading cause in family decisions to transfer patients from home to a care facility.

It's essential that caregivers receive adequate training on methods of managing sundowning behaviors. There are many simple management techniques that can help relieve patient and caregiver distress caused by sundowning. Surrounding the patient with familiar and comforting objects can be helpful. Caregivers should also be alert to changes in behavior that may be related to the presence of a specific caregiver because patients may have an aversion to someone providing care that reminds them of a traumatic event from their past.

Caregivers can alleviate patient stress by decreasing noise, eliminating clutter, and limiting the number of people in the room with the patient. It's important to keep the space well-lit because reduced lighting can result in shadows, which may be confusing and frightening to patients with cognitive impairment, resulting in increased agitation.

Caregivers should practice redirection, reassurance, and distraction in response to disruptive behavior. In addition to evaluating for environmental causes, healthcare providers should assess for any treatable underlying medical conditions, such as pain, constipation, or other physical ailments, that could exacerbate BPSD.

Improving quality of life

Current understanding of sundown syndrome is limited; therefore, further research is needed to conclusively determine the most appropriate treatments for sundowning behavior. The literature suggests that future studies should extend past just a few weeks and explore the response to various treatments at different times of the day. For now, we must rely on what's known about available treatments to improve patient quality of life and decrease caregiver burden.

cheat sheet

Sundowning symptoms

Figure
Figure
  • Confusion
  • Agitation
  • Aggression
  • Disorientation
  • Anxiety
  • Pacing
  • Wandering
  • Resistance to redirection
  • Screaming/yelling
  • Restlessness
  • Visual/auditory hallucinations

cheat sheet

Associated factors

Figure
Figure

Biological factors

  • Degeneration of SCN
  • Decreased melatonin production
  • Disrupted circadian rhythm
  • Impaired cholinergic neurotransmission

Physiologic factors

  • Unmet physical needs
  • Patient fatigue

Medical factors

  • Sleep disorders
  • Sensory deprivation
  • Pain

Environmental factors

  • Inadequate exposure to light
  • Caregiver fatigue
  • Environmental overstimulation

key points

Managing sundowning symptoms

Figure
Figure
  • Reduce noise and eliminate clutter.
  • Limit the number of people around the patient.
  • Use distraction and redirection.
  • Provide daytime exposure to light and adequate lighting in the evening to reduce confusion.
  • Encourage daily physical activity.
  • Ensure adequate rest and reduce evening stimulation.
  • Allow the patient to walk or pace as needed (with supervision) to reduce restlessness.
  • Schedule appointments or activities for the patient in the earlier part of the day when he or she is more alert and less agitated.
  • Keep a log of the circumstances surrounding instances of disturbed behavior to help avoid potential sundowning triggers in the future.
  • Discuss sleep disturbances with the healthcare provider.

Sundowning cycle

Symptoms of sundown syndrome can activate a treacherous cycle for patients and caregivers. Managing sundowning behaviors in the evening can exacerbate caregivers' stress at a time when they're particularly fatigued from a full day of caregiving. Patients often struggle to sleep soundly and may remain active or wander at night. Therefore, managing these patients can lead to caregiver exhaustion and burnout. A highly burdened caregiver may struggle to remember or use effective strategies for management of sundowning behaviors and may unintentionally display more frustration. The emotional distress presented by the caregiver can inadvertently influence the patient and cause him or her to experience an increase in anxiety and agitation, thus leading to more challenging behavioral disturbances.

Figure
Figure

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