Melatonin replacement therapy of elderly insomniacs

Sleep-inducing effects of exogenous melatonin administration

In this report current data is reviewed indicating that melatonin, the main hormone secreted by the pineal gland at night, participates in sleep regulation in humans. Evidence supporting this role relies on findings that abnormal melatonin secretion, induced by a variety of commonly used drugs, and in clinical disorders of the nervous system, are associated with sleep disturbances, and that melatonin has beneficial sleep-inducing effects in elderly melatonin-deficient insomniacs, and in children with sleep disorders. The time of melatonin administration, rather than the pharmacological dose, is a crucial factor regarding its potency as a sleep-inducing agent. Possible operating mechanisms explaining melatonin hypnotic effects are discussed.

Melatonin for the treatment of disorders in circadian rhythm and sleep: could it form a basis for medication?

The various aspects of the existing knowledge on the physiological role of melatonin and its mode of action in circadian rhythms and sleep are presented. Furthermore, the possibility of its clinical application in maintenance of sleep under regular and environmental changes is discussed.

Melatonin Pharmacotherapy for Nocturia in Men With Benign Prostatic Enlargement

PURPOSE

Nocturia is a common condition often attributed in aging men to benign prostatic enlargement. Older adults are prone to nocturnal sleep disturbance, of which disturbed circadian rhythm may be a component since it improves with nighttime administration of melatonin. This study was designed to investigate melatonin as a potential treatment for nocturia associated with bladder outflow obstruction in older men.

MATERIALS AND METHODS

A total of 20 men with urodynamically confirmed bladder outflow obstruction and nocturia were entered into a randomized, double blind, placebo controlled crossover study assessing the effect of 2 mg controlled release melatonin at night on nocturia. Symptoms were assessed at baseline and after each 4-week treatment period using a frequency volume chart, the International Prostate Symptom Score and symptom problem index. Maximum urinary flow rate and post-void residual urine volume were also assessed.

RESULTS

Baseline frequency of nocturia was 3.1 episodes per night. There were 7 men (35%) with detrusor overactivity and 10 (50%) had nocturnal polyuria. Melatonin and placebo caused a decrease in nocturia of 0.32 and 0.05 episodes per night (p = 0.07) and a decrease in the nocturia bother score of 0.51 and 0.05, respectively (p = 0.008). Nocturia responder rates (a reduction from baseline of at least -0.5 episodes per night) differed between the active medication and placebo groups (p = 0.04). Daytime urinary frequency, International Prostate Symptom Score, relative nocturnal urine volume, maximum urinary flow rate and post-void residual were unaffected by melatonin treatment.

CONCLUSIONS

Melatonin treatment is associated with a significant nocturia response rate, improvement in nocturia related bother and a good adverse effect profile. However, it is uncertain whether the observed changes in this study are clinically significant.

Insomnia in the geriatric patient

Insomnia in the geriatric patient is unique and complex, requiring a comprehensive and careful evaluation. Insomnia is the most common sleep complaint reported by persons > 60 years. It is defined as the inability to initiate or maintain sleep, and the etiology can be multifactorial. Insomnia in the geriatric patient may be due to a primary sleep disorder, such as obstructive sleep apnea, periodic limb movements in sleep, circadian rhythm disorders, or restless legs syndrome, or it may be secondary to underlying medical or psychiatric conditions, medication effects, or psychosocial factors. When insomnia becomes chronic, it may exacerbate medical and psychiatric illnesses. Insomnia can lead to excessive daytime sleepiness, which may result in disturbed intellect, impaired cognition, confusion, psychomotor retardation, or increased risk of injury, any of which can compromise the patient's quality of life and create social and economic burdens for caregivers. This article discusses the recommended diagnostic and treatment approaches that may be used by the clinician in treating the geriatric patient. Case studies are presented to illustrate diagnoses of insomnia and therapeutic interventions.

Nocturnal 6-sulfatoxymelatonin excretion in insomnia and its relation to the response to melatonin replacement therapy

PURPOSE

Melatonin, which is produced by the pineal gland at night, is an endogenous sleep regulator. Both sleep disorders and impaired melatonin production are common among the elderly. We examined the excretion of the major melatonin metabolite 6-sulfatoxymelatonin in insomnia patients aged >or=55 years and its relation with the subsequent response to melatonin therapy.

METHODS

We studied 517 insomnia patients, along with 29 age-matched and 30 younger healthy volunteers. Nocturnal urinary 6-sulfatoxymelatonin excretion was assessed between 10 pm and 10 am. Three hundred and ninety-six of the insomnia patients were treated for 2 weeks with placebo and for 3 weeks with 2 mg per night of controlled-release melatonin, of which 372 provided complete datasets. Clinical response, assessed with the Leeds Sleep Evaluation Questionnaire, was defined as an improvement of 10 mm or more on the visual analog scales.

RESULTS

Mean (+/- SD) 6-sulfatoxymelatonin excretion was lower in the insomnia patients (9.0 +/- 8.3 microg per night) than in volunteers of the same age (18.1 +/- 12.7 microg per night, P <0.05) and in younger volunteers (24.2 +/- 11.9 microg per night, P <0.05). About 30% of patients (112/372) excreted <or=3.5 microg of sulfatoxymelatonin per night, which is considered to be lower than normal for this age group. These "low excretors" had a significantly higher response to melatonin replacement therapy (58% [65/112] vs. 47% [122/260], P <0.05).

CONCLUSION

Low nocturnal melatonin production is associated with insomnia in patients aged 55 years or older, and identifies patients who are somewhat more likely to respond to melatonin replacement.

Disordered sleep, nocturnal cytokines, and immunity: interactions between alcohol dependence and African-American ethnicity

Sleep disturbance is one of the most prominent complaints of alcohol-dependent patients. In view of recent evidence that the immune system is integrated with other homeostatic processes ultimately regulated by the brain, the influence of sleep on host defense mechanisms and the expression of proinflammatory and T helper cell cytokines deserves attention in alcohol dependence. Although not all immune alterations found in alcohol-dependent persons are related to disordered sleep, it is exceedingly important to know whether sleep influences immunity in alcoholism because of the recognized impact of disordered sleep on infectious disease risk. Conversely, feedback systems are also operating between the brain and the immune system, and abnormalities in the expression of cytokines might contribute to sleep disturbances in alcohol-dependent persons. In this review, we identify the immune alterations found in association with alcohol dependence and discuss the implications of these findings for infectious disease risk, with particular attention to the interaction between African-American ethnicity and alcoholism in contributing to this risk. We provide evidence that sleep disruption occurs in association with alcohol dependence and that African-American alcohol-dependent persons show greater abnormalities in sleep and sleep regulatory processes than shown by Euro-American alcohol-dependent persons. The relations among alcoholism, sleep, and immunity are discussed, with an emphasis on understanding how the cytokine network is altered during sleep in the African-American alcohol-dependent populations. The potential is to use cytokine agonists or antagonists to determine whether physiologic changes in cytokines have a role in the homeostatic regulation of sleep in human beings, which has tremendous implications for the development of novel treatments of alcohol-related sleep disorders.

Abnormal nocturnal melatonin secretion and disordered sleep in abstinent alcoholics

BACKGROUND

Alcoholic patients show prominent disturbance of sleep as measured by electroencephalogram, with difficulties in the onset and maintenance of sleep. Given the role of melatonin in the regulation of the sleep-wake cycle, this study examined the relationship between nocturnal expression of melatonin and sleep in alcoholics as compared with control subjects.

METHODS

Alcoholic patients (n = 11) and comparison control subjects (n = 10) underwent all-night polysomnography and serial blood sampling every 30 min from 10:00 PM to 6:30 AM for measurement of circulating levels of melatonin and cortisol.

RESULTS

Coupled with prolonged sleep latency, alcoholics showed lower levels of melatonin during the early part of the night and a delay in the onset of the nocturnal plateau or peak value of melatonin as compared with control subjects. The nocturnal delay of melatonin correlated with prolonged sleep latency. Circulating levels of cortisol were lower during the early part of the night and higher in the late part of night in the alcoholics as compared with the control subjects.

CONCLUSIONS

A delay in the nocturnal rise of melatonin may contribute to disordered sleep in chronic alcoholics, with implications for the use of melatonin in the treatment of insomnia in recovering alcoholics.

Effect of controlled-release melatonin on sleep quality, mood, and quality of life in subjects with seasonal or weather-associated changes in mood and behaviour

This study aimed to explore the effects of melatonin on sleep, waking up and well being in subjects with varying degrees of seasonal or weather-associated changes in mood and behaviour. Fifty-eight healthy adults exhibiting subsyndromal seasonal affective disorder (s-SAD) and/or the negative or positive type of weather-associated syndrome (WAS) were randomised to either 2 mg of sustained-release melatonin or placebo tablets 1-2 h before a desired bedtime for 3 weeks. Outcome measures were changes from baseline in sleep quality, sleepiness after waking, atypical depressive symptoms and health-related quality of life by week three. Early morning salivary melatonin concentrations were measured at baseline and treatment cessation in all subjects. Melatonin administration significantly improved the quality of sleep (P=0.03) and vitality (P=0.02) in the subjects with s-SAD, but attenuated the improvement of atypical symptoms and physical parameters of quality of life compared to placebo in the subjects with WAS, positive type.

[Sleep rhythm disturbances in Alzheimer's disease]

PURPOSE

Sleep-wake rhythm disturbances observed in Alzheimer's disease are correlated with the severity of cognitive impairment and often result in institutionalization. These disturbances are also a major cause of psychotropic medication misuse. We report age-related physiologic and disease related pathologic changes in sleep-wake rhythms and propose chronobiological treatment approaches in patients with Alzheimer's disease.

CURRENT KNOWLEDGE AND KEY POINT

Alzheimer patients show a greater breakdown of the circadian sleep-wake cycle compared to similarly aged non demented controls. Demented patients spend their nights in a state of frequent restlessness and their days in a state of frequent sleepiness. These sleep-wake disturbances became increasingly more marked with progression of the disease. The architecture of sleep in Alzheimer's disease is marked by further decreases of slow wave sleep (SWS) and rapid eye movement (REM) sleep, and increases of time and frequency of awakening compared to age-matched control subjects. The sleep-wake disturbances in elderly people and particularly Alzheimer patients may result from changes at different levels: a reduction of environmental synchronizers or their perception, a lack of mental and physical activity, an age or disease related anatomical changes with loss of functionality of the biological clock(s).

FUTURE PROSPECTS AND PROJECTS

In Alzheimer patients, controlling sleep-wake disturbances with sedative drugs often increases both sleep disturbance and cognitive dysfunction. A chronobiological approach with bright-light therapy, melatonin administration, restricted time in bed, and diurnal activity may be an interesting therapeutic alternative in the management of sleep-wake disorders in Alzheimer patients. The aim of these therapeutics is to improve sleep and diurnal activity and consequently to increase the quality of life in Alzheimer patients.

Double blind randomised placebo controlled trial of low dose melatonin for sleep disorders in dementia

BACKGROUND

Disturbance of sleep is common in individuals with dementia where there may be reversal of the sleep-wake cycle. People with dementia of the Alzheimer's type have melatonin secretion rhythm disorders. There is some evidence that treatment with exogenous melatonin is an effective treatment for sleep disturbance associated with dementia. A randomised double blind placebo controlled cross over trial was undertaken to test the hypothesis that slow release exogenous melatonin 6 mg improves sleep for people with dementia.

METHODS

Forty-four participants with DSM-IV diagnoses of dementia with sleep disturbance were selected for a seven week randomised double blind cross over trial of slow release melatonin 6 mg versus placebo. Sleep parameters were objectively measured using wrist actigraphy.

RESULTS

Twenty-five out of 44 completed the trial. Sleep was significantly disturbed in the sample population. Melatonin had no effect on median total time asleep (n=25, z=1.35, p=0.18), number of awakenings (n=25, z=0.32, p=0.75) or sleep efficiency (n=25, z=0.17, p=0.24). Nor were there any carry over effects from melatonin.

CONCLUSIONS

Contrary to previous findings, we found no evidence that two weeks of exogenous melatonin is effective in improving sleep in people with dementia, although possible benefits of melatonin following longer periods of administration cannot be discounted.

Over-the-counter sleeping pills: a survey of use in Hong Kong and a review of their constituents

This study examined the composition of over-the-counter (OTC) sleeping pills in Hong Kong and reviewed the current knowledge about the hypnotic efficacy and safety of their major herbal and dietary supplement constituents. We conducted a cross-sectional survey of OTC sleep aids at drug stores in a residential district of 0.3 million population and literature search using MEDLINE, EMBASE, PsycINFO, China Journal Net, China Biomedical Database and relevant English and Chinese literature. We identified 17 brands of OTC sleeping pill: eleven of them were composed of mixtures of Chinese and Western herbal agents and six brands contained 3 mg of melatonin. The Chinese herbal mixture suanzaorentang, comprising zizyphi spinosi semen, poria cocos, ligusticum wallichii, anemarrhenae rhizoma and glycyrrhizae radix in ratio of 7:5:2:1:1, was the most common OTC sleeping pill available in the survey. Our literature review showed that kava, valerian and melatonin were the better-researched herbs and dietary supplements, however, the data on hypnotic efficacy and safety was inadequate to support their clinical use. More rigorous investigations of the risk-benefit relationship of herbal agents and dietary supplements used for insomnia are needed.

Therapy of circadian rhythm disorders in chronic fatigue syndrome: no symptomatic improvement with melatonin or phototherapy

BACKGROUND

Patients with chronic fatigue syndrome (CFS) show evidence of circadian rhythm disturbances. We aimed to determine whether CFS symptoms were alleviated by melatonin and bright-light phototherapy, which have been shown to improve circadian rhythm disorders and fatigue in jet-lag and shift workers.

DESIGN

Thirty patients with unexplained fatigue for > 6 months were initially assessed using placebo and then received melatonin (5 mg in the evening) and phototherapy (2500 Lux for 1 h in the morning), each for 12 weeks in random order separated by a washout period. Principal symptoms of CFS were measured by visual analogue scales, the Shortform (SF-36) Health Survey, Mental Fatigue Inventory and Hospital Anxiety and Depression Scale. We also determined the circadian rhythm of body temperature, timing of the onset of melatonin secretion, and the relationship between these.

RESULTS

Neither intervention showed any significant effect on any of the principal symptoms or on general measures of physical or mental health. Compared with placebo, neither body temperature rhythm nor onset of melatonin secretion was significantly altered by either treatment, except for a slight advance of temperature phase (0.8 h; P = 0.04) with phototherapy.

CONCLUSION

Melatonin and bright-light phototherapy appear ineffective in CFS. Both treatments are being prescribed for CFS sufferers by medical and alternative practitioners. Their unregulated use should be prohibited unless, or until, clear benefits are convincingly demonstrated.

Tolerability of hypnosedatives in older patients

Sleep disturbances are common and prevalence rates increase with age. Especially in the elderly, somatic diseases and medications with adverse effects relating to sleep are frequent reasons for disturbed and nonrefreshing sleep. It should be emphasised that these reasons must be excluded before symptomatic therapy is started. In some cases the use of hypnosedatives may be included as part of the treatment of a somatic disease and may cause sleep disturbances. Pharmacotherapy is one of the main approaches in the management of primary insomnia and should be part of a broader treatment strategy including nonpharmacological methods. This article focuses on the tolerability of frequently prescribed hypnosedatives in the elderly with primary insomnia and addresses the primary care physician. In general, recommendations for the pharmacotherapy of insomnia in elderly patients include using a reduced dosage. For some substances (e.g. zolpidem, zopiclone, zaleplon, temazepam and triazolam) the recommended dosage is half that recommended for younger patients. The properties of the selected hypnosedative should be taken into consideration and matched with the type of sleep disturbance experienced by the patient. Ultrashort-acting drugs may be useful when initiating sleep is the main problem, whereas short- and intermediate-acting substances are recommended for maintaining sleep. Possible interactions with pre-existing medication must also be taken into consideration. Some agents such as antipsychotics, antidepressants, melatonin and herbal agents may be used in specific indications. However, only a few of these substances have proven tolerability in the elderly and further investigations are recommended.

Senescence, sleep, and circadian rhythms

The goal of this review article is to summarize our knowledge and understanding of the overlapping (interdisciplinary) areas of senescence, sleep, and circadian rhythms. Our overview comprehensively (and visually wherever possible), emphasizes the organizational, dynamic, and plastic nature of both sleep and circadian timing system (CTS) during senescent processes in animals and in humans. In this review, we focus on the studies that deal with sleep and circadian rhythms in aged animals and how these studies have closely correlated to and advanced our understanding of similar processes in ageing humans. Our comprehensive summary of various aspects of the existing research on animal and human ageing, both normal and pathological, presented in this review underscores the invaluable advantage of close collaboration between clinicians and basic research scientists and the future challenges inherent in this collaboration. First, our review addresses the common age-related changes that occur in sleep and temporal organization of both animals and humans. Second, we examine the specific modifications that often accompany sleep and CTS during aging. Third, we discuss the clinical epidemiology of sleep dysfunctions during ageing and their current clinical management, both pharmacological and non-pharmacological. Finally, we predict the possible future promises for complementary and alternative medicine (CAM) that pave the way to the emergence of a "Holistic Sleep Medicine" approach to the treatment of sleep disorders in the ageing population. Further studies will provide additional valuable insights into the understanding of both sleep and circadian rhythms during senescence.

Residual effects of daytime administration of melatonin on performance relevant to flight

There is a general consensus that melatonin possesses time-dependent hypnotic effects, but there is no information yet whether it has residual effects on neurobehavioral performance, especially after daytime administration. In the present study we investigated the possible residual effects of 3 mg melatonin on performance relevant to flight and on subjective feelings of sleepiness, arousal, activation and affect after a daytime nap, as a function of nap length. Fifteen reserve pilots of the Israeli Air Force participated in the study. The experiment consisted of four sessions during which either melatonin or placebo was administered at 16:00 h. In two conditions, subjects were allowed to sleep for 2 h (17:00-19:00 h) whereas in the other two only a 0.5-h nap was allowed. After the naps they started performing a flight simulator task every 2 h. Sleep efficiency significantly increased and sleep latency significantly decreased in both melatonin conditions compared to placebo. Flight performance was only mildly affected in the 0.5-h nap condition. Subjective assessment of sleepiness significantly differed between the two treatment conditions, only in the 0.5-h nap condition. Subjects felt sleepier 2-4 h after melatonin administration. To conclude, our data suggest that administration of melatonin before a brief daytime nap (about 0.5 h) may be associated with mild residual effects on psychomotor performance and may significantly affect subjective feeling of sleepiness for 2-4 h.

The role of actigraphy in sleep medicine

During the last decade actigraphy (activity-based monitoring) has become an essential tool in sleep research and sleep medicine. The validity, reliability and limitations of actigraphy for documenting sleep-wake patterns have been addressed. Normative data on sleep-wake patterns across development have been collected. Multiple studies have documented the adequacy of actigraphy to distinguish between clinical groups and to identify certain sleep-wake disorders. Actigraphy has also been shown to be effective in documenting the effects of various behavioral and medical interventions on sleep-wake patterns. Actigraphy is less useful for documenting sleep-wake in individuals who have long motionless periods of wakefulness (e.g. insomnia patients) or who have disorders that involve altered motility patterns (e.g. sleep apnea). Potential users should be aware of a number of pitfalls of actigraphy: (1) validity has not been established for all scoring algorithms or devices, or for all clinical groups; (2) actigraphy is not sufficient for diagnosis of sleep disorders in individuals with motor disorders or high motility during sleep; (3) the use of computer scoring algorithms without controlling for potential artifacts can lead to inaccurate and misleading results.

Sleep changes and disorders in the elderly patient

Sleep disorders are very common among older patients. Our population as a whole is experiencing substantial growth in the geriatric population. Thus, it is all the more prudent that healthcare professionals become familiar with the major sleep disorders that affect the older patient, as well as the diagnosis and treatment of these disorders. This paper deals with the various sleep changes that take place in the course of the aging process and with the assessment of sleep disorders in the older patient. Special attention is paid to sleep-disordered breathing, periodic limb-movement disorder of sleep, insomnia, and circadian rhythm anthology, as well as parasomnias that are unique to the older patient. The final section of the paper deals with specific neurologic disorders and their impact on sleep patterns.

Peak of circadian melatonin rhythm occurs later within the sleep of older subjects

We investigated the relationship between sleep timing and the timing of the circadian rhythm of plasma melatonin secretion in a group of healthy young and older subjects without sleep complaints. The timing of sleep and the phase of the circadian melatonin rhythm were earlier in the older subjects. The relationship between the plasma melatonin rhythm and the timing of sleep was such that the older subjects were sleeping and waking earlier relative to their nightly melatonin secretory episode. Consequently, the older subjects were waking at a time when they had higher relative melatonin levels, in contrast with younger subjects, whose melatonin levels were relatively lower by wake time. Our findings indicate that aging is associated not only with an advance of sleep timing and the timing of circadian rhythms but also with a change in the internal phase relationship between the sleep-wake cycle and the output of the circadian pacemaker. In healthy older subjects, the relative timing of the melatonin rhythm with respect to sleep may not play a causal role in sleep disruption.

Hypothermic action of exogenously administered melatonin is dose-dependent in humans

The pineal hormone melatonin (MLT) is closely related to sleep initiation and maintenance in humans, and is now used as a potent therapeutic tool for some circadian rhythm sleep disorders. Acute and transient hypothermia induced by exogenously administered MLT (ex-MLT) may play a critical role in the circadian phase shifting and hypnogenic actions. Six healthy young male volunteers (mean age, 22.5 y; age range, 19-24 y), whose endogenous MLT secretion rhythms were previously assessed, took either 0.5 mg, 3 mg, or 9 mg of ex-MLT or a placebo at 0930 h (the average sleep onset time was 0000 h) on a randomized, single-blind, crossover basis. In comparison with placebo, ex-MLT significantly suppressed core body temperature at the 3-mg and 9-mg doses and slightly suppressed core body temperature at the 0.5-mg dose. There was significant positive correlation between the magnitude of core body temperature suppression and the area under the MLT concentration curve as well as the peak MLT concentration after ex-MLT administration. Our study showed that clinical doses of ex-MLT induce hypothermia in a dose-dependent manner. Results suggest that the therapeutic effect of larger doses of ex-MLT should be tested on patients who benefit little from typically lower clinical doses of ex-MLT.

Circadian rhythm sleep disorders: pathophysiology and potential approaches to management

An intrinsic body clock residing in the suprachiasmatic nucleus (SCN) within the brain regulates a complex series of rhythms in humans, including sleep/wakefulness. The individual period of the endogenous clock is usually >24 hours and is normally entrained to match the environmental rhythm. Misalignment of the circadian clock with the environmental cycle may result in sleep disorders. Among these are chronic insomnias associated with an endogenous clock which runs slower or faster than the norm [delayed (DSPS) or advanced (ASPS) sleep phase syndrome, or irregular sleep-wake cycle], periodic insomnias due to disturbances in light perception (non-24-hour sleep-wake syndrome and sleep disturbances in blind individuals) and temporary insomnias due to social circumstances (jet lag and shift-work sleep disorder). Synthesis of melatonin (N-acetyl-5-methoxytryptamine) within the pineal gland is induced at night, directly regulated by the SCN. Melatonin can relay time-of-day information (signal of darkness) to various organs, including the SCN itself. The phase-shifting effects of melatonin are essentially opposite to those of light. In addition, melatonin facilitates sleep in humans. In the absence of a light-dark cycle, the timing of the circadian clock, including the timing of melatonin production in the pineal gland, may to some extent be adjusted with properly timed physical exercise. Bright light exposure has been demonstrated as an effective treatment for circadian rhythm sleep disorders. Under conditions of entrainment to the 24-hour cycle, bright light in the early morning and avoidance of light in the evening should produce a phase advance (for treatment of DSPS), whereas bright light in the evening may be effective in delaying the clock (ASPS). Melatonin, given several hours before its endogenous peak at night, effectively advances sleep time in DSPS and adjusts the sleep-wake cycle to 24 hours in blind individuals. In some blind individuals, melatonin appears to fully entrain the clock. Melatonin and light, when properly timed, may also alleviate jet lag. Because of its sleep-promoting effect, melatonin may improve sleep in night-shift workers trying to sleep during the daytime. Melatonin replacement therapy may also provide a rational approach to the treatment of age-related insomnia in the elderly. However, there is currently no melatonin formulation approved for clinical use, neither are there consensus protocols for light or melatonin therapies. The use of bright light or melatonin for circadian rhythm sleep disorders is thus considered exploratory at this stage.

Melatonin and sleep qualities in healthy adults: pharmacological and expectancy effects

The impact of expectancy on melatonin's effects on sleep qualities was investigated. Both the pharmacological dose of 6 mg of melatonin and the expectation of receiving melatonin were predicted to improve subjective ratings of sleep qualities. The balanced placebo design varied 2 factors within-subjects: actual treatment and expected treatment. Adults (N = 53; 21 men and 32 women) between the ages of 26 and 71 years were administered either 6 mg of melatonin or a placebo for 8 nights. An instructional manipulation directed participants' expectations. Participants rated their nightly sleep experiences. Results revealed that feelings upon awakening differed between genders and that expecting melatonin increased ratings of sleep continuity. Most important, high ratings of "grogginess/tiredness" were associated with receiving melatonin, regardless of expectancy, as well as with receiving placebo when melatonin was expected. Overall, the findings underscore the need to consider expectancy and gender differences in research on melatonin and sleep experiences.

Influence of sleep deprivation coupled with administration of melatonin on the ultrastructure of rat pineal gland

The effects of sleep deprivation with or without melatonin treatment on the pineal morphology in rats were studied. Five days after sleep deprivation and using electron microscopy, many of the pinealocytes exhibited structural alterations including dilation of the cisternae of the rough/smooth endoplasmic reticulum, Golgi saccules and mitochondria, and an increase in the numbers of lipid droplets, vacuoles and dense-core vesicles. These features were considered as morphological evidence of increased synthesis or secretion by the pineal gland. In addition, numerous membranous profiles, considered to be degraded cellular organelles, were observed in some pinealocytes and sympathetic nerve terminals. It is suggested that the occurrence of degenerating organelles had resulted from the deleterious effect of sleep deprivation. This may be attributed to an overload of secretory activity of the pineal gland during stress elicited by the long-term sleep deprivation, leading to functional exhaustion and irreversible damage of the oxidation-related organelles. In sleep-deprived rats receiving a single injection of melatonin (10 mg/kg) for 5 consecutive days, the above features indicative of pinealocytic activation were attenuated. In fact, all signs of degeneration of cellular organelles were rarely found. These results suggest that the pineal gland is itself a target for exogenously administered melatonin. Thus, melatonin when administered systemically may be used as a potential neuroprotective drug against neuronal damage induced by sleep deprivation.

Human aging and melatonin. Clinical relevance

Melatonin is a hormone produced mainly by the pineal gland and secreted primarily at night, when it reaches levels 10 times higher than those present in the daytime. The highest melatonin levels are found in children younger than 4 yr; thereafter melatonin levels begin to decline with age. As a chronobiotic, melatonin acts on sleep by phase-advancing or delaying the sleep--wake cycle so that sleep onset occurs earlier or later than usual. Beneficial effects of melatonin have been observed in delayed and advanced sleep phase syndromes. These effects depend on the time that the hormone is administered. Melatonin is also used for jet lag and has been tried in shift workers and night workers to re-entrain their desynchronized rhythms. Melatonin also has free radical-scavenging properties that have primarily been observed in vitro at pharmacological concentrations.

Melatonin rhythm abnormalities and sleep disorders in the elderly

Biological aging is often associated with sleep problems and daytime napping. Complaints of difficulty in initiating and maintaining sleep, as well as daytime drowsiness, are more common in the elderly than in any other age group. This report reviews evidence that impaired melatonin secretion is associated with sleep disorders in old age. Circulating melatonin levels have been found to be significantly lower and onset and peak times have been delayed in elderly insomniacs as compared to age-matched control subjects. In view of these findings, we investigated the effects of melatonin treatment on melatonin-deficient insomnia in the elderly. From the results of our study, it seems likely that melatonin replacement therapy may be beneficial in the initiation and maintenance of sleep in this population.

Herbs and nutrients in the treatment of depression, anxiety, insomnia, migraine, and obesity

Although a multitude of pharmaceutical agents are available for the treatment of mood disorders, anxiety and insomnia, many patients have difficulty tolerating the side effects, do not respond adequately, or eventually lose their response. Many therapeutic herbs and nutrients have far fewer side effects and may provide an alternative treatment or can be used to enhance the effect of prescription medications. In the article, the authors review the quality of the evidence supporting the clinical effects of a number of commonly used types of complementary/alternative medicine (CAM) for mood disorders, anxiety, and insomnia. They review data on the use of St. John's Wort, S-adenosyl-methionine (SAM-e), B vitamins, inositol, omega-3 fatty acids, and choline for mood disorders; data on the use of kava and other herbal agents and fish extract for anxiety and insomnia; and data on valerian and melatonin for insomnia. The authors also discuss the use of CAM to treat migraines, which may be comorbid with mood and anxiety disorders, and obesity, which can occur as a side effect of psychotropic medications. They consider the data on feverfew and butterbur for migraines and on chromium picolinate and the combination of ephedrine and caffeine for obesity. The authors also review issues related to comorbid medical illness, side effects, drug interactions, dosage, and brand selection.

Diminished melatonin secretion in the elderly caused by insufficient environmental illumination

The pineal hormone melatonin has some circadian regulatory effects and is assumed to have a close relation with sleep initiation and maintenance. Many previous reports have described age-related decreases in melatonin levels, especially in elderly insomniacs (EIs), which may act as causal or exacerbating factors in sleep disturbances in the elderly. Ten elderly residents with psychophysiological insomnia (mean age, 74.2 yr), 10 healthy residents of the same home [elderly control (EC) group; mean age, 72.7 yr], and 10 healthy young control subjects (mean age, 20.9 yr) living at home participated in this study. The elderly persons, especially the EIs, were exposed to significantly less environmental light and simultaneously suffered from significantly diminished nocturnal melatonin secretion. Supplementary exposure to 4 h (1000 to 1200 h, 1400 to 1600 h) of midday bright light in the EI group significantly increased melatonin secretion to levels similar to those in the young control group without circadian phase-shifting. There was a tendency for the magnitude of the increase in nocturnal melatonin secretion stimulated by bright light to parallel amelioration of sleep disturbances in these subjects. The present findings suggest that we need to pay attention to elderly individuals who suffer under conditions of poor environmental light resulting in disorganized circadian rhythms, including the sleep-wake cycle.

Circadian and sleep disturbances in the elderly

The incidence of disturbed sleep is strongly increased in healthy and demented elderly. Age-related alterations in the circadian timing system appear to contribute strongly to these problems. With increasing age, a lack of input to the suprachiasmatic nucleus (SCN), the biological clock of the brain, may accelerate de-activation of neurons involved in the generation of 24-h rhythm or output of this rhythm. This process appears to be reversible, since supplementation of stimuli that impinge on the SCN can re-activate these neurons and ameliorate disturbances in the sleep-wake rhythm.

Assessment and treatment of sleep disturbances in older adults

Sleep disturbances are common in older adults. These disturbances are often secondary to medical illness and/or medication use or are due to specific problems such as sleep disordered breathing, periodic limb movements in sleep and circadian rhythm disturbances. The prevalence of sleep disordered breathing and periodic limb movement in sleep increases with age. The circadian rhythm tends to advance with age, causing older people to awaken early in the morning. Insomnia is often caused by pain associated with medical illness. Insomnia can also be caused by stimulating medications. In institutionalized elderly, sleep becomes even more disturbed and fragmented than in community-dwelling older adults. Accurate assessment and diagnosis is crucial since effective treatment strategies are available for these sleep disturbances. The effect, prevalence and treatment of each of these conditions is reviewed.

Effect of exogenous melatonin on mood and sleep efficiency in emergency medicine residents working night shifts

OBJECTIVE

To determine whether melatonin taken prior to attempted daytime sleep sessions will improve daytime sleep quality, nighttime sleepiness, and mood state in emergency medicine (EM) residents, changing from daytime to nighttime work schedules.

METHODS

A prospective, randomized, double-blind crossover design was used in an urban emergency department. Emergency medicine residents who worked two strings of nights, of at least three nights' duration each, and separated by at least one week of days were eligible. Subjects were randomized to receive either melatonin 1 mg or placebo, 30 to 60 minutes prior to their daytime sleep session, for three consecutive days after each night shift. Crossover to the other agent occurred during their subsequent night shifts. Objective measures of quality of daytime sleep were obtained using the Actigraph 1000. This device measures sleep motion and correlates with sleep efficiency, total sleep time, time in bed, and sleep latency. The Profile of Mood States (POMS) and the Stanford Sleepiness Scale (SSS) were also used to quantify nighttime mood and sleepiness.

RESULTS

Among the 19 volunteers studied, there was no difference in sleep efficiency (91.16% vs 90.98%, NS), sleep duration (379.6 min vs 342.7 min, NS), or sleep latency (7.59 min vs 6.80 min, NS), between melatonin and placebo, respectively. In addition, neither the POMS total mood disturbance (5.769 baseline vs 12.212 melatonin vs 5.585 placebo, NS) nor the SSS (1.8846 baseline vs 2.2571 melatonin vs 2.1282 placebo, NS) demonstrated a statistical difference in nighttime mood and sleepiness between melatonin and placebo.

CONCLUSIONS

There are no beneficial effects of a 1-mg melatonin dose on sleep quality, alertness, or mood state during night shift work among EM residents.

Melatonin for treatment of sundowning in elderly persons with dementia - a preliminary study

This pilot study investigated the impact of melatonin administration as a clinical intervention for improving sleep and alleviating sundowning in 11 elderly nursing home residents who suffer from dementia. Melatonin is a hormone produced and secreted by the pineal gland in response to darkness, which plays a major role in the induction and regulation of sleep. Melatonin production decreases with age. Age-related sleep disorders are frequently associated with disruption of circadian cycle rhythms, and sometimes with 'sundowning'. Sundowning refers to the manifestation of agitation and/or confusion in the evening hours. Agitation has been linked to sleep disorders. Analysis revealed a significant decrease in agitated behaviors in all three shifts, and a significant decrease in daytime sleepiness. There was a nonsignificant decrease in latency (time to fall asleep) during the evening shift and no significant changes were reported in night-time sleep ratings. The results of this study are important, because finding ways of decreasing sundowning in elderly persons may improve their well being, alleviate the burden of the caregivers, and even enable caregiving in a less restrictive environment.

Circadian rhythms and sleep in human aging

This issue of Chronobiology International is dedicated to the age-related changes in circadian rhythms as they occur in humans. It seems timely to give an overview of the knowledge and hypotheses on these changes now that we enter a century in which the number and percentage of elderly in the population will be unprecedented. Although we should take care not to follow the current tendency to think of old age as a disease--ignoring the fine aspects of being old--there is definitely an age-related increase in the risk of a number of conditions that are at least uncomfortable. Circadian rhythms have been attributed adaptive values that usually go unnoticed, but can surface painfully clear when derangements occur. Alterations in the regulation of circadian rhythms are thought to contribute to the symptoms of a number of conditions for which the risk is increased in old age (e.g., sleep disturbances, dementia, and depression). A multidisciplinary approach to investigate the mechanisms of age-related changes in circadian regulation eventually may result in treatment strategies that will improve the quality of life of the growing number of elderly. Although diverse topics are addressed in this issue, the possible mechanisms by which a deranged circadian timing system may be involved in sleep disturbances receives the most attention. This seems appropriate in view of the numerous studies that have addressed this relation in the last decade and also because of the high frequency and strong impact of sleep disturbances in the elderly. This introduction to the special issue first briefly addresses the impact of disturbed sleep in the elderly to show that the development of therapeutic methods other than the currently available pharmacological treatments should be given high priority. I believe that chronobiological insights may play an important role in the development of rational therapeutical methods.

More than a marker: interaction between the circadian regulation of temperature and sleep, age-related changes, and treatment possibilities

The neurobiological mechanisms of both sleep and circadian regulation have been unraveled partly in the last decades. A network of brain structures, rather than a single locus, is involved in arousal state regulation, whereas the suprachiasmatic nucleus (SCN) has been recognized as a key structure for the regulation of circadian rhythms. Although most models of sleep regulation include a circadian component, the actual mechanism by which the circadian timing system promotes--in addition to homeostatic pressure--transitions between sleep and wakefulness remains to be elucidated. Little more can be stated presently than a probable involvement of neuronal projections and neurohumoral factors originating in the SCN. This paper reviews the relation among body temperature, arousal state, and the circadian timing system and proposes that the circadian temperature rhythm provides an additional signaling pathway for the circadian modulation of sleep and wakefulness. A review of the literature shows that increased brain temperature is associated with a type of neuronal activation typical of sleep in some structures (hypothalamus, basal forebrain), but typical of wakefulness in others (midbrain reticular formation, thalamus). Not only local temperature, but also skin temperature are related to the activation type in these structures. Warming of the skin is associated with an activation type typical of sleep in the midbrain reticular formation, hypothalamus, and cerebral cortex (CC). The decreasing part of the circadian rhythm in core temperature is mainly determined by heat loss from the skin of the extremities, which is associated with strongly increased skin temperature. As such, alterations in core and skin temperature over the day could modulate the neuronal activation state or "preparedness for sleep" in arousal-related brain structures. Body temperature may thus provide a third signaling pathway, in addition to synaptic and neurohumoral pathways, for the circadian modulation of sleep. A proposed model for the effects of body temperature on sleep appears to fit the available data better than previous hypotheses on the relation between temperature and sleep. Moreover, when the effects of age-related thermoregulatory alterations are introduced into the model, it provides an adequate description of age-related changes in sleep, including shallow sleep and awakening closer to the nocturnal core temperature minimum. Finally, the model indicates that appropriately timed direct (passive heating) or indirect (bright light, melatonin, physical activity) manipulation of the nocturnal profile of skin and core temperature may be beneficial to disturbed sleep in the elderly. Although such procedures could be viewed by researchers as merely masking a marker for the endogenous rhythm, they may in fact be crucial for sleep improvement in elderly subjects.

Supplementary administration of artificial bright light and melatonin as potent treatment for disorganized circadian rest-activity and dysfunctional autonomic and neuroendocrine systems in institutionalized demented elderly persons

Increased daytime napping, early morning awakening, frequent nocturnal sleep interruptions, and lowered amplitude and phase advance of the circadian sleep-wake rhythm are characteristic features of sleep-waking and chronobiological changes associated with aging. Especially in elderly patients with dementia, severely fragmented sleep-waking patterns are observed frequently and are associated with disorganized circadian rhythm of various physiological functions. Functional and/or organic deterioration of the suprachiasmatic nucleus (SCN), decreased exposure to time cues such as insufficient social interaction and reduced environmental light, lowered sensitivity of sensory organs to time cues, and reduced ability of peripheral effector organs to express circadian rhythms may cause these chronobiological changes. In many cases of dementia, the usual treatments for insomnia do not work well, and the development of an effective therapy is an important concern for health care practitioner and researchers. Recent therapeutical trials of supplementary administration of artificial bright light and the pineal hormone melatonin, a potent synchronizer for mammalian circadian rhythm, have indicated that these treatments are useful tools for demented elderly insomniacs. Both bright light and melatonin simultaneously ameliorate disorganized thermoregulatory and neuroendocrine systems associated with disrupted sleep-waking times, suggesting a new, potent therapeutic means for insomnia in the demented elderly. Future studies should address the most effective therapeutic design and the most suitable types of symptoms for treatment and investigate the use of these tools in preventive applications in persons in early stages of dementia.

Sleep-wake cycle, sleep-related disturbances, and sleep disorders: a chronobiological approach

There is convincing evidence that the functions of sleep include restoration of brain energy storage and memory consolidation. The circadian timing system (CTS) is involved in the daily variation of almost any physiological and psychological variable evaluated thus far. Disturbances of the CTS can be clinically observed by their influence on the sleep-wake cycle, hormones, body temperature, and locomotor activity. This article reviews the basic mechanisms of circadian rhythm sleep disturbances, names the applicable diagnostic tools and specific therapeutic strategies, and thereby hints at the impact of circadian rhythm sleep disturbance on psychiatric disorders, especially disorders of affect and cognition. In light of the preventive, diagnostic, and therapeutic tools now available, a new round of chronobiological studies in psychiatry seems justified, promising, and necessary.

In vitro pituitary responsiveness to LHRH in young and old female rats. Influence of melatonin

The effect of aging and melatonin on in vitro pituitary responsiveness to luteinizing hormone-releasing hormone (LHRH) was studied. Young cyclic (3-months-old) control (cyclic-control, N = 15), and melatonin (MEL) treated for 2 months (150 microg/100 g BW) (cyclic-MEL, N = 15), old acyclic (23-months-old) control (acyclic-control, N = 13), and MEL-treated (acyclic-MEL, N = 18) rats were used. The hormones analyzed were luteinizing hormone (LH), follicle stimulating hormone (FSH) and prolactin (PRL). The results showed a different influence of the reproductive status as well as of melatonin on the basal secretion rate of both gonadotropins, i.e. LH and FSH. Only the basal FSH release was significantly reduced in cyclic-MEL and acyclic-controls compared to cyclic-controls. The hemipitutary FSH content raised to values similar to those observed for FSH secretion and only the cyclic-MEL group showed significantly higher FSH pituitary content than for release. LHRH addition to the incubation medium resulted in increased LH release for both cyclic and acyclic rats, but FSH release was only stimulated in acyclic rats. Melatonin treatment blunted this response in both cases. In addition, melatonin treatment inhibited prolactin release in acyclic-MEL group after LHRH stimulation but not the basal levels. Pituitary LH and prolactin contents, were significantly higher than the pituitary LH and prolactin levels released from all groups studied, and were not affected by reproductive senescence nor by exogenous melatonin. These data indicate that aging influences more the secretory than the biosynthetic processes. Melatonin influences is endocrine status-dependent, being inhibitory when pituitary hormones reach their higher values.

Urinary 6-sulfatoxymelatonin excretion and aging: new results and a critical review of the literature

The apparent age-related decline in melatonin production has been thought to continue in a secular manner across the lifespan. While it is clear that melatonin levels in children and adolescents are elevated compared to older individuals, the question of whether there is a sudden or gradual change has not been adequately addressed. In this study, we report the excretion of the melatonin metabolite, 6-sulfatoxymelatonin in 253 subjects aged between 21 and 82 yr. The correlation with age was significant (r = -0.24; P < 0.05). When the data was analysed by ANOVA using 5-yr age spans, there was a significant effect of age, but post hoc analysis indicated that after 25 yr of age there was no significant decline in excretion of the metabolite. Thus, although the oldest subjects excreted 36% less melatonin metabolite than the youngest, the decrease occurred at a very early age. In the second part of the study, we re-evaluated the data from seven previous studies that measured plasma melatonin levels or metabolite excretion across a wide range of ages and 11 studies comparing young versus older subjects. Statistical analysis by ANOVA again suggested that the changes in melatonin occurring with age were essentially complete before 30 yr of age. The youngest subjects produced at the most twice the amount of melatonin as the oldest subjects. Finally, we evaluated the mean plasma melatonin levels in 144 groups of normal subjects reported in 137 separate publications with respect to age. Again, whereas there was a significant correlation with age, ANOVA showed that there was no difference between groups after 35 yr of age, and the oldest groups had levels that were only 43% of the youngest groups. We conclude that melatonin production is lower in older people, but that the change occurs very early in life, around 20-30 yr of age.

Predictors of subjective sleepiness induced by melatonin administration

Researchers have found that melatonin substantially reduced both sleep onset latency and the number of nocturnal awakenings in normal individuals as well as patients with diverse sleep pathologies. These findings have led to an increase in the number of individuals who ingest melatonin habitually to alleviate their sleep problem. Given the widespread use of melatonin, it is important to identify the factors capable of predicting physiological states while following a melatonin regimen. The result of this preliminary analysis showed that the number of hours spent outdoors is the best predictor of subjective sleepiness while under the influence of melatonin. Specifically, the more time individuals spend outdoors, the sleepier they are when administered melatonin.

Physiological levels of melatonin contribute to the antioxidant capacity of human serum

This work evaluates whether physiological concentrations of the pineal secretory product melatonin contribute to the total antioxidant status (TAS) of human serum. Day and nighttime serum samples were collected from healthy volunteers ranging from 2 to 89 years of age and used to measure melatonin and TAS. Results showed that both melatonin and TAS in human serum exhibited 24 hr variations with nocturnal peak values at 01:00 hr. Moreover, exposure of volunteers to light at night resulted in clear decreases of both TAS and melatonin. Furthermore, when melatonin was removed from sera collected at night, the TAS value of the sample was reduced to basal daytime values. In aging studies, it was found that nocturnal serum values of TAS and melatonin exhibited maximal values during the first four decades; thereafter, these values decreased as age advanced. In 60-year-old individuals, day/night differences in serum melatonin and TAS levels were clearly diminished, by more than 80%, with these differences being completely abolished in older individuals. Our results suggest that melatonin contributes to the total antioxidative capability of human serum. This antioxidant contribution of melatonin is reduced as age advances correlating with the age-related reduction of melatonin.