Introduction
The light from the moon casts long shadows across your bedroom wall. Your spouse breathes softly beside you. You are wide awake once again at four a.m. Your frustration grows the longer you lie awake. You wonder how you will be able to function at work tomorrow with so little rest.
What is it?
Sleep disorders can be temporary or long-term problems and can affect the quantity or quality of sleep achieved. There are four recognized types of sleeping disorders:
- Extrinsic sleep disorders, caused by something outside of the body such as drug use or a poor sleep environment
- Intrinsic sleep disorders, caused by something within the body such as a physical or psychological ailment
- Dyssomnias, characterized by an abnormality in the amount, quality, or timing of sleep. For example, insomnia, narcolepsy, breathing-related sleep disorders, and circadian rhythm sleep disorders, which are disruptions in your regular daily biological clock such as jet lag or work shift changes
- Parasomnias, characterized by unusual physical occurrences during sleep such as sleepwalking, grinding teeth or bed-wetting
Insomnia, is defined as difficulty falling asleep, difficulty maintaining sleep or sleeping but not feeling rested. Insomnia can be caused by any one of the four types of sleep disorders mentioned above.
The National Institutes of Mental Health has identified three broad categories of insomnia. These include:
- Transient - insomnia lasting fewer than three days
- Short-term - lasting three days to three weeks
- Chronic - lasting more than three weeks
There are many elements about the mechanisms of sleep and wakefulness that scientists do not understand. What is known is that sleep is primarily controlled by two systems in the brain: one that induces sleep and sleep-related processes, and one that regulates sleep within a 24-hour cycle. This cycle, which corresponds to periods of light and darkness, is known as the circadian rhythm cycle. Researchers are discovering that this cycle is a process controlled by genes that are found in living creatures ranging from the lowly fruit fly to human beings.
Researchers know that as human beings we go through a variety of stages of sleep that can be measured by brain wave patterns. Sleep is divided into two phases: non-rapid eye movement (NREM) sleep and rapid eye movement (REM) sleep. There are many cycles of NREM and REM sleep, each lasting between 70 and 120 minutes. Sleep disorders result from either internal abnormalities or external disturbances to these cycles. The feeling of having had enough sleep, or sleep satiety, is related to whether one has gone through all of the cycles of sleep, including both dreamless and REM sleep. We typically cycle through these stages multiple times per night.
The ongoing study of sleep disorders spans many medical fields, including neuroscience, genetics, physiology and psychology. Some of the mechanisms that play a role in sleep disorders are the subject of study at The National Center for Sleep Disorders Research. This center is situated within the National Heart, Lung, and Blood Institute - part of the National Institutes of Health (NIH) in Bethesda, Maryland. Research includes the study of the genes that play a role in narcolepsy (a condition characterized by brief attacks of deep sleep), how sleep disturbances affect the immune system, and the role of sleep/wake cycles in triggering heart attacks.
Who has it?
About 40 million people in the U.S. suffer from sleep problems every year. Insomnia is the most prevalent sleep complaint among adults in America. Insomnia is more common among the elderly and women.
Sleep apnea, a disruption of breathing during sleep, affects nearly 18 million people in the U.S. More than one billion dollars are spent each year on sleep medications in the United States.
What are the risk factors?
Most short-term sleep disorders are caused by one or more of the following factors:
- lifestyle changes, such as marriage, retirement, or unemployment
- stressful situations, such as the death of a loved one or job pressure
- physical disorders
- environment
Chronic sleep disorders have numerous possible causes. These include:
- medical conditions - especially those producing pain
- psychiatric conditions such as depression
- drug use (including alcohol, nicotine, or caffeine)
- environments that are not conducive to sleep
Many conditions that cause sleep disorders are associated with the elderly, which could explain why insomnia is 1.5 times more common in people older than age 65. In addition to physical conditions that disrupt sleep, elderly people tend to experience changes in sleep patterns leading to fewer hours of quality sleep per night.
Women, especially those who are postmenopausal, are more likely to suffer from sleep disorders than men. However, laboratory studies show that men are more likely to experience disrupted sleep patterns than women.
What are the symptoms?
The symptoms of sleep disorders include:
- difficulty or inability to fall asleep
- awaking early from sleep
- easy disruption of sleep
- fatigue or sleepiness
- anxiety
- lack of concentration
- irritability
Lifestyle changes and proper sleep hygiene (click on the Helping Yourself box) may be helpful for short-term management of insomnia. Medications may also help relieve insomnia and re-establish regular sleep patterns. Management of chronic insomnia requires careful assessment of the underlying cause for the insomnia, as well as nonpharmacologic therapy and less frequent use of sedative-hypnotics to prevent tolerance and dependence.
Over-the-counter sleep aids that contain diphenhydramine (Benadryl), an antihistamine, may be helpful for short-term bouts of insomnia. Because the body can grow accustomed to antihistamine sleep aids, they often lose their effectiveness the more you take them. If you experience continued bouts of insomnia you should talk to your doctor to see if prescription medications are needed. Benzodiazepines are commonly used for the management of sleep disorders. Short-acting benzodiazepines are less likely than long-acting benzodiazepines to be associated with drowsiness or sluggishness the next morning. Benzodiazepines are only available with a prescription. They are controlled substances and do carry a potential for addiction if used inappropriately.
Other drugs used in the management of insomnia include unique agents called non-benzodiazepine sedative hypnotics. Examples include Ambien (zolpidem), Sonata (zaleplon), and Lunesta (eszopiclone).
Drug classes also considered sedative hypnotics are barbiturates and sedating antihistamines. The non-benzodiazepines and barbiturates are also controlled substances due to the potential for addiction.
A newer class of sedative hypnotics is also available. Rozerem (ramelteon), a melatonin receptor agonist, mimics the body's natural sleep promoting hormone, melatonin. This drug class is unique because it works with the body's natural circadian rhythm to promote sleep. These melatonin receptor agonists are not controlled substances and do not carry an addiction potential.
Natural remedies have been used for years to treat sleep disorders. One of the most popular "natural" remedies for insomnia has been melatonin, which can be obtained at most pharmacies and health food stores. Melatonin is a hormone that is known to be involved in the regulation of sleep and wakefulness. It has been shown that the ingestion of melatonin prior to bedtime will help individuals fall asleep. However, scientific data have failed to confirm that melatonin is useful in maintaining sleep.
Herbal products such as valerian, chamomile, kava kava, and others have also been promoted as natural remedies for insomnia. However, these herbals are not regulated by the Food and Drug Administration (FDA) and the effectiveness and safety of these products has not been documented in large clinical trials.
Drug classes used to treat Sleep Disorders
- Barbiturates
- Benzodiazepines
- Miscellaneous Sedatives and Hypnotics
