Sundowning, also known as sundown syndrome, is a complex and distressing phenomenon primarily affecting individuals with dementia or Alzheimer's disease.

It is characterized by a marked increase in confusion, agitation, and other behavioral changes that begin in the late afternoon or early evening and often persist into the night.

Defining Sundowning and Its Symptoms

Sundowning manifests as a pattern of behavioral and cognitive disturbances that typically arise as daylight wanes. Key symptoms include confusion, anxiety, irritability, restlessness, and even hallucinations or delusions.

Individuals who exhibit sundowning may become notably disoriented about their surroundings, sometimes wandering or shadowing caregivers, and experiencing significant mood swings ranging from agitation to sadness.

This constellation of symptoms can worsen progressively as the night deepens, often culminating in disrupted sleep. While sundowning is most prevalent among middle to late-stage dementia patients, it may also appear sporadically in other settings or neurological conditions.

Importantly, the condition is not officially classified in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), yet research estimates that approximately 20 to 45 percent of people with Alzheimer's disease experience some form of sundowning during their illness progression.

Understanding Causes and Mechanisms

Though the precise causes remain unclear, sundowning is believed to result from a combination of neurological, environmental, and physiological factors. One prominent theory relates to deterioration of the brain regions governing circadian rhythms—internal biological clocks that regulate sleep-wake cycles.

In dementias like Alzheimer's, damage to the suprachiasmatic nucleus (SCN) disrupts these cycles, leading to confusion and agitation as daylight fades.

Other contributing factors include fatigue accumulated over the day, low levels of ambient light provoking anxiety, and sensory overstimulation or deprivation. Medications can also exacerbate symptoms by causing side effects such as dizziness or confusion. Furthermore, unmet physical needs like hunger, pain, or discomfort, as well as emotional triggers such as depression or stress, may precipitate sundowning episodes.

Triggers Amplifying Sundowning Episodes

Environmental and contextual triggers significantly influence the severity and frequency of sundowning. Reduced visibility and increasing shadows during twilight can induce fear or misinterpretation of surroundings. Unfamiliar settings heighten disorientation, complicating recognition of space and people.

Noise, activity levels, and the emotional state of caregivers also contribute—stress or exhaustion perceived by the individual can aggravate symptoms.

Managing Sundowning and Improving Quality of Life

Effective management of sundowning involves a multidisciplinary approach focusing on symptom relief and environmental modifications.

Non-pharmaceutical interventions often serve as first-line strategies, including maintaining regular sleep schedules, optimizing exposure to natural light, and engaging patients in calming, familiar activities during late afternoon. Avoiding stimulants such as caffeine in the evening and reducing daytime napping help preserve night-time sleep quality.

When behavioral symptoms severely disrupt life, medication may be necessary; however, these must be used cautiously given potential side effects in elderly populations. Addressing underlying physical discomforts and ensuring emotional support are crucial components of care.

Education and support for caregivers are equally vital, providing techniques to manage stress and recognizing signs early to prevent escalation. Recognizing sundowning as a symptom rather than a deliberate behavior fosters patience and empathy during challenging periods.

"Sundowning refers to a sense of (increased confusion and changes in behavior) that can occur in people with Alzheimer's disease and other dementias toward the end of the day," explains Keith Vossel, M.D., a professor of neurology and director of the Mary S. Easton Center for Alzheimer's Research and Care at UCLA in California.

Sundowning represents a significant and multifaceted challenge for individuals with dementia and their caregivers, marked by late-day cognitive and behavioral disturbances. It arises from disruptions in the brain's circadian regulation compounded by environmental and physiological stressors. Understanding the condition's symptoms, causes, and triggers allows for better management and improved quality of life through targeted interventions and empathetic care.