Melatonin Helps Sundowning and Other Sleep Disorders
For many elderly people who suffer from Alzheimer’s disease or other forms of dementia, sunset can be a time of increased memory loss, confusion, agitation and even anger.
Sundowning is a dementia-related symptom that refers to increased agitation, confusion and hyperactivity that begins in the late afternoon and builds throughout the evening.
For family members who care for those with dementia, witnessing an increase in their loved one’s symptoms of disorientation at sunset can be nothing short of troubling, if not also painful, frightening and exhausting.
Scientists don’t completely understand why sleep disturbances occur with Alzheimer’s disease and dementia. As with changes in memory and behavior, sleep changes somehow result from the impact of Alzheimer’s on the brain.
Some studies indicate as many as 20 percent of persons with Alzheimer’s will experience increased confusion, anxiety and agitation beginning late in the day. Others may experience changes in their sleep schedule and restlessness during the night. This disruption in the body’s sleep-wake cycle can lead to more behavioral problems.
Factors that may contribute to sundowning and sleep disturbances include:
- End-of-day exhaustion (both mental and physical)
- An upset in the “internal body clock,” causing a biological mix-up between day and night
- Reduced lighting and increased shadows causing people with Alzheimer’s to misinterpret what they see, and become confused and afraid
- Reactions to nonverbal cues of frustration from caregivers who are exhausted from their day
- Disorientation due to the inability to separate dreams from reality when sleeping
- Less need for sleep, which is common among older adults
Circadian Rhythms and the Biological Clock
Although most people tend to think that manifestations of body function such as temperature and blood pressure are constant throughout the day, the fact is that many functions change in cyclic patterns—especially those that are affected by hormones, such as cortisol.
These daily fluctuations, or circadian rhythms (from Latin: “about one day”), are fundamental to all organisms, from bacteria to human beings. Circadian rhythms help coordinate and synchronize our internal body functions, as well as our interactions with the external world.
Scientists are still learning about how the body maintains this synchronicity with its environment. Here is some of what they’ve found.
Deep within the brain, in the anterior hypothalamus, lies the suprachiasmatic nucleus (SCN), a dual cluster of thousands of nerve cells. This is the body’s circadian pacemaker, popularly known as the biological clock, which is powered, in a sense, by light.
The SCN receives signals from the outside world via the retina of the eye (the back inside lining of the eyeball, analogous to the film in a camera). When light strikes the retina, bioelectric signals are generated and sent to the SCN via a neural pathway called the retinohypothalamic tract. Signals are also sent, of course (via the optic nerve), to the visual cortex, where the sensation of vision is produced.
Melatonin—The Biological Clock’s Hour Hand
The signals that reach the SCN are processed and forwarded to a small number of other hypothalamic nuclei and to the destination of primary importance, the pineal gland. This is an endocrine gland whose pea size proves that, at least in terms of physiological importance, size doesn’t matter. What makes the pineal gland so important is the hormone it secretes: melatonin. This compound is the end product of a biosynthetic pathway that begins with the nutrient amino acid tryptophan.
Through a series of enzyme-catalyzed reactions, tryptophan is partially converted to 5-hydroxytryptophan (5-HTP), which is partially converted to serotonin, which is partially converted to melatonin. (How “partial” each of these conversions is depends on many factors governed by prevailing chemical conditions in different parts of the body.)
Lights Out = Melatonin On
The relationship between light and melatonin is inverse. When the SCN is stimulated by daylight signals from the retina, it instructs the pineal gland to suppress melatonin production (though not entirely). Then, when daylight fades in the evening, the SCN’s lack of stimulation is signaled to the pineal gland, and melatonin secretion is increased many times over, creating a physiological condition of “biological night” in the person.
The circadian rhythm of melatonin secretion is so tied to the day/night cycle that the daily duration of the secretion (at high levels) is shorter during the summer, when the nights are short, and longer during the winter, when the nights are long.
By directly controlling the pineal gland’s melatonin secretion, the SCN indirectly controls many of the body’s circadian rhythms, including those affected by jet lag. Consequently, many physicians recommend supplemental melatonin for relieving the symptoms of this condition.
Studies have shown that melatonin is effective in phase-shifting human circadian rhythms either forward or backward, giving long-distance travelers welcome relief from both the physical and psychological effects of jet lag.
Melatonin Is Good for Insomnia
Melatonin has also been used successfully for treating insomnia. In a newly published meta-analysis on the effects of supplemental melatonin on sleep, the authors analyzed the data from 17 previously published studies and concluded that melatonin can significantly decrease sleep latency (the time it takes to fall asleep) and increase sleep efficiency and sleep duration.1
The fact that melatonin can be used for treating insomnia is especially relevant to the elderly. As people grow older, sleep problems, including difficulty in falling asleep and staying asleep, become common. This is probably because a general disruption of circadian rhythms associated with declining melatonin production is characteristic of the aging process.
With melatonin levels declining as we age, it makes sense to think that melatonin supplements (taken in the evening, of course) may be able to help us achieve a good night’s sleep.
Melatonin Deficiency May Cause Sundowning
There is evidence that melatonin may also be able to help relieve some of the symptoms of an emerging twenty-first-century epidemic: Alzheimer’s disease (AD).
First described clinically in 1906, AD is the most common cause of dementia in those aged 65 or older. With the rapidly aging population in the United States (it’s estimated that 30% of the population will be 65 or older by the year 2050), projections are that 14 million people will develop this devastating disease during the next four decades.2,3
You may notice big changes in how your loved one with Alzheimer’s act in the late afternoon or early evening. Fading light seems to be the trigger. The symptoms can get worse as the night goes on and usually get better by morning.
Disruption of the sleep/wake cycle is highly characteristic of AD, and a commonly observed problem in AD patients is a phenomenon called sundowning. This is a worsening (during the evening hours) of a constellation of cognitive and behavioral symptoms associated with the disease.
When someone is sundowning, they may be:
- Agitated (upset or anxious)
They also may:
- Hear or see things that aren’t there
- Have mood swings
Up to 1 out of 5 people with Alzheimer’s get sundown syndrome. But it can also happen to older people who don’t have dementia.
Although there is no clear answer as to why this occurs, many researchers are coming to believe that declining melatonin levels may play a significant role.
A study in Current Neuropharmacology shows that Melatonin secretion decreases in Alzheimer´s disease (AD) and this decrease has been postulated as responsible for the circadian disorganization, decrease in sleep efficiency and impaired cognitive function seen in those patients.
Studies also show that Alzheimer’s patients with disturbed sleep-wake rhythms not only exhibited reduced amounts of melatonin secreted, but also a higher degree of irregularities in the pattern of the melatonin rhythm.
According to scientific research, melatonin replacement has been shown effective to treat sundowning and other sleep wake disorders in AD patients. Numerous controlled trials found improvement in such objective characteristics of sleep quality as total sleep time, sleep efficiency, and wake time during sleep as a result of melatonin treatment, as well as a trend toward decreased sundowning and improved sleep quality. Several recent studies which reflect use of melatonin specifically in patients with dementia, demonstrated that melatonin reduces sundowning behavior, nocturnal activity, decreases sleep latency, and improves quality of sleep.
Melatonin May Help Alleviate Alzheimer’s Disease
A recent review by scientists at the Netherlands Institute for Brain Research in Amsterdam explains that declining melatonin production in the aged can not only affect their circadian rhythms but also play a role in the development and characteristics of Alzheimer’s disease itself.4
The authors cite research showing that aging is characterized by a progressive deterioration of circadian rhythms, due at least in part to degenerative changes in the SCN and the pineal gland, which result in diminished melatonin production.
They go on to cite studies showing that, in AD patients, the biological clock (SCN) is severely impaired, and the resultant degree of impairment of melatonin secretion is related to the severity of the mental impairment caused by the disease.
They state, “AD patients with disturbed sleep-wake cycle possess melatonin secretion rhythm disorders, and the disappearance of daily melatonin rhythm in AD patients is consistent with clinical circadian rhythm disorders, such as delirium, agitation, and sleep-wake disturbance.”
While it’s common in mainstream medical practice to use sedatives such as benzodiazepines, and antipsychotics such as haloperidol, to try to ameliorate the sundowning and sleep disturbances so commonly seen in Alzheimer’s patients, these drugs do little or nothing to help, and in some cases they may even exacerbate the problems.
This makes the use of melatonin supplementation seem all the more attractive by comparison, especially since it’s designed to rectify the very deficiency that caused the problem in the first place. The Dutch authors go on to state,
In AD patients, melatonin [supplementation] has been suggested to improve circadian rhythmicity, decreasing agitated behavior, confusion, and ‘sundowning’ in uncontrolled studies. Melatonin has also been suggested to have beneficial effects on memory in AD, possibly through protection against oxidative stress and neuroprotective capabilities.
Melatonin Is an Antioxidant and Neuroprotector
Oxidative damage to the brain caused by free radicals is thought to play a significant role in the cognitive impairments characteristic of Alzheimer’s, a disease in which free radicals are produced in much greater amounts then normal. These excess free radicals are known to cause significant damage to the brain, including the actual death of many neurons.
A review paper in 2000 reported that, in the autopsied brains of Alzheimer’s patients, there were many hallmark pathological changes caused by free radical activity, including oxidative damage to DNA, proteins, and lipids.5
Melatonin has significant antioxidant and neuroprotective properties, and it is believed that they may be important with regard to its role in aging and Alzheimer’s disease. It is intriguing to note that the precursor molecule 5-HTP (which can be taken as a supplement for the purpose of boosting serotonin levels) has recently been found to have a much higher antioxidant activity than melatonin.6
If your loved one experiences sundowning, it’s certainly worth trying a nightly dose of melatonin to see if it helps re-set their body clock.
Experts also suggest these lifestyle tips to help minimize sundowning behaviors:
- Try to maintain a predictable routine for bedtime, waking, meals and activities.
- Plan for activities and exposure to light during the day to encourage nighttime sleepiness.
- Limit daytime napping.
- Limit caffeine and sugar to morning hours.
- Keep a night light on to reduce agitation that occurs when surroundings are dark or unfamiliar. See The Right Lighting Prevents Falls.
- 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.
- Talk with your loved one’s doctor if you suspect an underlying condition, such as a urinary tract infection or sleep apnea, might be worsening sundowning behavior.
When sundowning occurs in a care facility, it may be related to the flurry of activity during staff shift changes or the lack of structured activities in the late afternoon and evening. Staff arriving and leaving may cue some people with Alzheimer’s to want to go home or to check on their children — or other behaviors that were appropriate in the late afternoon in their past. It may help to occupy their time with another activity during that period.
Do you have any tips to help sundowning? Please share your thoughts and experience below.
- Brzezinski A, Vangel MG, Wurtman RJ, et al. Effects of exogenous melatonin on sleep: a meta-analysis. Sleep Med Rev 2005;9(1):41-50.
- Grundman M, Thal L. Treatment of Alzheimer’s disease. Neurol Clin 2000;18(4):807-28.
- Mayeux R, Sang M. Treatment of Alzheimer’s disease. New Engl J Med 1999;341:1670-9.
- Wu YH, Swaab DF. The human pineal gland and melatonin in aging and Alzheimer’s disease. J Pineal Res 2004 Dec 21 (online pub date).
- Christen Y. Oxidative stress and Alzheimer’s disease. Am J Clin Nutr 2000;71(2):621-9.
- Keithahn C, Lerchi A. 5-Hydroxytryptophan is a more potent in vitro hydroxyl radical scavenger than melatonin or vitamin C. J Pineal Res 2005;38:62-6.
Recommended: The 36-Hour Day, 5th Edition
Originally published in 1981, The 36-Hour Day was the first book of its kind. Thirty years later, with dozens of other books on the market, it remains the definitive guide for people caring for someone with dementia.
Now in a new and updated edition, this best-selling book features thoroughly revised chapters on the causes of dementia, managing the early stages of dementia, the prevention of dementia, and finding appropriate living arrangements for the person who has dementia when home care is no longer an option.
Recommended: Surviving Alzheimer’s –
Practical tips and soul-saving wisdom for caregivers
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