Sleep disorders, sleepiness and traffic safety: a public health menace.

Sleep disorders are not uncommon and have been widely reported throughout the world. They have a profound impact on industrialized 24-h societies. Consequences of these problems include impaired social and recreational activities, increased human errors, loss of productivity, and elevated risk of accidents. Conditions such as acute and chronic insomnia, sleep loss, excessive sleepiness, shift-work, jet lag, narcolepsy, and sleep apnea warrant public health attention, since residual sleepiness during the day may affect performance of daily activities such as driving a car. Benzodiazepine hypnotics and zopiclone promote sleep, both having residual effects the following day including sleepiness and reduced alertness. In contrast, the non-benzodiazepine hypnotics zolpidem and zaleplon have no significant next-day residual effects when taken as recommended. Research on the effects of wakefulness-promoting drugs on driving ability is limited. Countermeasures for excessive daytime sleepiness have a limited effect. There is a need for a social awareness program to educate the public about the potential consequences of various sleep disorders such as narcolepsy, sleep apnea, shift-work-related sleep loss, and excessive daytime sleepiness in order to reduce the number of sleep-related traffic accidents.

Sleep disorders, sleepiness and traffic safety: a public health menace

Sleep disorders are not uncommon and have been widely reported throughout the world. They have a profound impact on industrialized 24-h societies. Consequences of these problems include impaired social and recreational activities, increased human errors, loss of productivity, and elevated risk of accidents. Conditions such as acute and chronic insomnia, sleep loss, excessive sleepiness, shift-work, jet lag, narcolepsy, and sleep apnea warrant public health attention, since residual sleepiness during the day may affect performance of daily activities such as driving a car. Benzodiazepine hypnotics and zopiclone promote sleep, both having residual effects the following day including sleepiness and reduced alertness. In contrast, the non-benzodiazepine hypnotics zolpidem and zaleplon have no significant next-day residual effects when taken as recommended. Research on the effects of wakefulness-promoting drugs on driving ability is limited. Countermeasures for excessive daytime sleepiness have a limited effect. There is a need for a social awareness program to educate the public about the potential consequences of various sleep disorders such as narcolepsy, sleep apnea, shift-work-related sleep loss, and excessive daytime sleepiness in order to reduce the number of sleep-related traffic accidents.

Underlying sleep pathology may cause chronic high fatigue in shift-workers.

About 20-25% of the population in primary healthcare settings complains of chronic fatigue but this symptom has been under-emphasized compared with sleepiness in clinical practice. Shift-workers are particularly vulnerable because of various fatigue-related personal and public morbidity and mortality. The goal of this cross-sectional study was to explore if fatigue severity could be used as an independent predictive tool to identify underlying sleep pathology. The 21 most-fatigued (study group) and 23 least-fatigued (control) miners were selected on the basis of the Fatigue Severity Scale (FSS), which was administered to 195 subjects in an underground mine in Timmins, a town in northern Ontario. The two groups were matched for age, gender, and body mass index (BMI). Mean FSS score for the most-fatigued subjects was 4.9 +/- 0.5 and the least-fatigued was 2.2 +/- 0.5 (P < 0.0001). The subjects from each group were studied polysomnographically to identify sleep disorders. The polysomnographic data in 15 of 21 (71.4%) of the most-fatigued subjects displayed significant sleep pathology compared with only three of 23 (13.0%) in the least-fatigued subjects. Based on Fisher's exact test, the difference between the two groups was highly significant (P < 0.0001). Also, in the total subject pool (n = 195), the correlation between subjective fatigue and sleepiness was not very strong (Pearson's r = 0.45), suggesting that these two symptoms can be independent phenomena. It is concluded that chronic high fatigue can be an independent manifestation of underlying sleep pathology, which warrants independent subjective and objective assessment.

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.

A randomized, double-blind, placebo-controlled crossover study of the effect of exogenous melatonin on delayed sleep phase syndrome.

OBJECTIVE: The effects of exogenous melatonin on sleep, daytime sleepiness, fatigue, and alertness were investigated in 22 patients with delayed sleep phase syndrome whose nocturnal sleep was restricted to the interval from 24:00 to 08:00 hours. This study was a randomized, double-blind, placebo-controlled crossover trial. Subjects received either placebo or melatonin (5 mg) daily for 4 weeks, underwent a 1-week washout period, and then were given the other treatment for an additional 4 weeks. Patients could take the melatonin between 19:00 and 21:00 hours, which allowed them to select the time they felt to be most beneficial for the phase-setting effects of the medication. METHODS: Two consecutive overnight polysomnographic recordings were performed on three occasions: at baseline (before treatment), after 4 weeks of melatonin treatment, and after 4 weeks of placebo treatment. RESULTS: In the 20 patients who completed the study, sleep onset latency was significantly reduced while subjects were taking melatonin as compared with both placebo and baseline. There was no evidence that melatonin altered total sleep time (as compared with baseline total sleep time), but there was a significant decrease in total sleep time while patients were taking placebo. Melatonin did not result in altered scores on subjective measures of sleepiness, fatigue, and alertness, which were administered at different times of the day. After an imposed conventional sleep period (from 24:00 to 08:00), subjects taking melatonin reported being less sleepy and fatigued than they did while taking placebo. CONCLUSIONS: Melatonin ameliorated some symptoms of delayed sleep phase syndrome, as confirmed by both objective and subjective measures. No adverse effects of melatonin were noted during the 4-week treatment period.

The relationship between subjective sleep estimation and objective sleep variables in depressed patients.

INTRODUCTION: To our knowledge there is no evidence in the literature about the relationship between subjective sleep estimation and objective sleep variables in depression. It is not known whether the subjective estimation of sleep quality and sleep duration is directly related to any objective sleep variable in depressed patients. METHODS: Thirty patients with major depression and 10 healthy subjects have been investigated in our sleep laboratory during 1 or 2 consecutive nights after 1 night for adaptation. Every subject, after final awakening in the laboratory, answered questions concerning the subjective feelings about sleep duration, number of awakenings and sleep depth. We compared the sleep estimation in both groups and calculated the correlation between objective and subjective sleep variables in depressed patients. RESULTS: The degree of a wrong sleep estimation in depressed patients is larger than in healthy subjects. Slow wave sleep (SWS) in depressed patients correlates positively with the subjective estimation of sleep duration. Eye movement density in REM sleep correlates with the subjective estimation of the number of awakenings. CONCLUSION: SWS in depression has a positive influence on the subjective feeling of sleep duration while phasic REM sleep activity has a negative influence.

Interrelationships between nocturnal sleep, daytime alertness, and sleepiness: two types of alertness proposed.

The authors studied daytime sleepiness and alertness (based on the Multiple Sleep Latency Test [MSLT] and Maintenance of Wakefulness Test [MWT]) and nocturnal sleep in 22 patients with depression/anxiety and in 47 nondepressed patients with sleep apnea. The patients underwent two overnight sleep studies followed by daytime tests. In depressed patients, MWT scores correlated negatively with total sleep time and stage 3. MSLT scores correlated negatively with total sleep time and with sleep efficiency. Apneic patients showed a negative correlation between MWT results and amount of stage 1 sleep. MSLT results correlated positively with sleep onset latency on the preceding overnight sleep study. Thus, in depressed patients, there is a paradox that with more disturbed sleep there is greater daytime alertness. In contrast, the more disturbed the sleep is in sleep apnea patients, the more difficult it is to maintain daytime alertness.

Melatonin, sleep, and circadian rhythm disorders.

In the 1970s and early 1980s, neuroendocrinology was viewed by many neuroscientists as a ""window to the brain" to an understanding of brain function." In psychiatry, many have viewed sleep physiology as a window in biological psychiatry. This is, in part, because sleep is one of the few easily quantifiable functions of interest to psychiatrists. Melatonin is a hormone with powerful effects on behavior particularly circadian and sleep behavior. In contrast with other hormones, the pathophysiology and pathology of abnormal melatonin secretion is poorly understood. In this article, we document the well-established phase-shifting and sleep-promoting effects of melatonin and discuss some implications for neuropsychiatrists when the neurophysiology of melatonin goes array. It is both striking and in some ways not surprising that the majority of patients with phase delay syndrome described in our research studies have been misdiagnosed as having depression. The reason for this is elucidated in this article and the information concerning this condition may be helpful to many who are relatively unfamiliar with this particular sleep disorder. We can anticipate that patients with specific neurological disorders may have changes in their melatonin secretion and future research, for example in patients with head injury and conditions such as retinitis pigmentosa may be the basis for reviews a few years hence.

Diagnostic values of polysomnography in forensic medicine.

A man accused of a first-degree murder of a two-year-old girl claimed that he had not been conscious during the time of the alleged murder. The possibility that he may have committed the crime while "sleepwalking" was raised. The forensic psychiatrist looked to the sleep disorders facility to conduct polysomnographic investigation of the accused in order to investigate the possibility that he had a parasomnia. Overnight sleep recordings with video surveillance carried out for two consecutive nights showed no evidence of parasomnia. On the basis of the full assessment, the final report of the forensic psychiatrist did not support a legal defense of non-insane automatism and "sleepwalking" was withdrawn as a possible defense by the lawyer of the accused.

REM sleep in depressed patients: different attempts to achieve adaptation.

Twenty-seven depressed patients and 10 healthy subjects were investigated in the sleep laboratory during two to three consecutive nights. Eleven of the 27 patients demonstrated the "first night effect" (group I) and 11 other patients demonstrated a clear absence of the "first night effect" (group II). Five of the 27 depressed patients were omitted from the study because they did not fit criteria for first night effect. The 10 healthy controls demonstrated a first night effect. In group I, the duration of the first rapid eye movement (REM) sleep episode was increased on the first night and on the second night the REM sleep latency was decreased, whereas REM sleep duration and eye movement (EM) density was increased. The number of the short sleep cycles (less than 40 minutes) was greater in group I versus group II and the percentage of slow-wave sleep (SWS) was also higher in group I. In depressed patients with the "first night effect" the enhanced REM sleep requirement is satisfied not only by an increased REM sleep duration but also by the improved REM sleep quality that is crucial for adaptation. The adaptive role of the increased first REM period and the increased EM density in this period is very limited.