Sleep Disorders – Causes, Signs and Symptoms

Sleep Disorders


Sleep disorders are any difficulties related to sleeping. They may include difficulty falling or staying asleep, falling asleep at inappropriate times, sleeping excessively or abnormal behaviors during sleep.

More than 70 million Americans have a sleep disorder, according to the National Institutes of Health. Among those, almost 60 percent have a chronic disorder. Sleep disorders affect people of all ages, especially infants and elders.

More than 100 sleep disorders have been identified, including insomnia, sleep apnea, narcolepsy, restless legs syndrome, night terrors and sleepwalking.

Sleep disorders may be caused by a variety of factors. Medical conditions (e.g., asthma) or the use of certain medications may affect sleep. Lifestyle factors, such as working the night shift, may also contribute.

Signs and symptoms of sleep disorders may include difficulty falling asleep, waking up during the night and excessive daytime drowsiness.

Sleep disorders may take time to diagnose. If the cause of the sleep problem is not apparent, patients may be referred to a sleep center where sleep patterns are analyzed.

Treatment of sleep disorders varies depending on the cause of the disorder. Treatment may include lifestyle changes (such as avoiding caffeine and alcohol), losing weight, exercising and medications. Patients may also receive relaxation therapy or cognitive behavioral therapy (CBT). Left untreated, some sleep disorders can be life-threatening. Excessive daytime sleepiness can cause people to fall asleep at inappropriate times, such as while driving.

About sleep disorders

Sleep disorders are disturbances of usual sleep patterns or behaviors.

Sleep disorders may involve:

  • Difficulty falling asleep or staying asleep
  • Falling asleep at inappropriate times
  • Excessive total sleep time
  • Abnormal behaviors during sleep

Researchers have studied the sleep cycle for more than 50 years. It is not entirely understood. Chemical substances called neurotransmitters control sleep and wakefulness by affecting neurons (nerve cells) in the brain. Neurotransmitters, such as serotonin and norepinephrine, keep parts of the brain active while awake. When sleep begins, neurons in the base of the brain “switch off” the signals that maintain wakefulness.

Researchers measure sleep based on the electrical activity of the brain and other parts of the body. Sleep can be divided into five stages:

  • Stage 1. Light transitional sleep. People are drowsy and drift in and out of sleep. They awaken readily from this stage. When awakened, people may remember bits of visual images. People may experience sudden muscle contractions (hypnic myoclonia) often preceded by a sense of falling. Stage 1 represents about 5 percent of sleep time in a normal sleep cycle. People with some sleep disorders have more periods of stage 1 sleep.

  • Stage 2. Eye movement stops and brain waves (fluctuations of electrical activity) become slower, with occasional bursts of rapid waves (sleep spindles). About 50 percent of sleep is stage 2 sleep.

  • Stage 3. Dramatically slower brain waves (delta waves) begin to appear along with smaller, faster waves.

  • Stage 4. Delta waves predominate during this stage. Stages 3 and 4 are called deep sleep. It is difficult to wake people during these stages. When awakened during this stage, people often feel disoriented and groggy. Children sometimes experience bedwetting, night terrors or sleepwalking during deep sleep.

  • REM (rapid eye movement) sleep. Breathing becomes more rapid, irregular and shallow and the eyes move rapidly in various directions. Limbs become temporarily paralyzed. Heart rate and blood pressure increase and males develop erections. People often dream during REM sleep.

Sleep progresses in a cycle from stage 1 through REM sleep. A complete sleep cycle takes an average of 90 to 110 minutes. The first period of REM sleep usually occurs about 70 to 90 minutes after falling asleep. The first sleep cycle each night contains relatively short REM periods and long deep sleep periods. As sleep progresses, REM sleep periods increase and deep sleep decreases. By the end of the sleep period, people spend nearly all their time in stages 1, 2 and REM sleep.

Although sleep is necessary to survival, sleep requirements vary. Infants generally require about 16 hours of sleep a day and teenagers need about 9 hours. Most adults require 7 to 8 hours, although daily requirements may range from 5 to 10 hours. Women in the first three months of pregnancy often need several more hours of sleep than usual. As people age, they tend to sleep more lightly and for shorter periods of time, although they generally need about as much sleep as they did in early adulthood.

Sleep disorders are extremely common, but many are undiagnosed and untreated. More than 70 million Americans have a sleep disorder, according to the National Institutes of Health. Among those, almost 60 percent have a chronic disorder.

Sleep disorders affect people of all ages, including about 25 percent of children between the ages of 1 and 5 years, according to the National Center on Sleep Disorders Research (NCSDR). Of all the age groups, infants and elderly people are most likely to experience problems with sleep. About half of people over age 65 have frequent sleep problems. Sleep disturbances in the elderly may be a normal part of aging, a result of medical or psychiatric problems or a side effect of the increased intake of medications used to treat these problems.

The incidence of some sleep disorders increases with age, and with the number of older Americans increasing, it is estimated that nearly 80 million Americans will have a sleep problem by 2010 and 100 million will have one by 2050, according to the NCSDR.

Sleep disorders, sleep deprivation and sleepiness result in billions of dollars in health costs each year in the United States. Other impacts include reduced worker productivity and automobile accidents. Sleep disorders have also been linked to obesity, heart disease, strokes, diabetes and other health problems.

Types and differences of sleep disorders

More than 100 disorders of sleeping and waking have been identified, according to the National Institutes of Health. They may fall into one of the following categories:

  • Dyssomnias. Disturbances in the amount, timing or quality of sleep resulting in excessive daytime sleepiness or insomnia. Common dyssomnias include:

    • Insomnia. Condition of inadequate or poor sleep that may include difficulty falling asleep, waking up frequently during the night with difficulty falling back asleep, waking up too early in the morning or unrefreshing sleep. This is the most common type of sleep disorder.

    • Sleep apnea. Sleep disorder that causes breathing to become shallow or stop while sleeping. Each pause in breath usually lasts 10 to 20 seconds. Pauses can occur 20 to 30 times in an hour. This is the second most common sleep disorder. Left untreated, sleep apnea can be life-threatening. Excessive daytime sleepiness can cause people to fall asleep at inappropriate times, such as while driving. Sleep apnea also appears to increase a person’s risk of numerous health conditions including high blood pressure (hypertension), heart attack, stroke and diabetes.

    • Hypersomnia. Excessive daytime sleepiness after adequate nighttime sleep.

    • Restless legs syndrome (RLS). Sleep disorder characterized by unpleasant sensations in the legs that are described as creeping, crawling, tingling, pulling or painful.

    • Narcolepsy. Chronic sleep disorder characterized by excessive and overwhelming daytime sleepiness and short “sleep attacks,” even after adequate nighttime sleep. About 250,000 Americans have narcolepsy, according to the National Center on Sleep Disorders Research. Its cause is unknown.

    • Periodic limb movement disorder (nocturnal myoclonus). Characterized by periodic episodes of repetitive jerking and kicking during sleep.

    • Circadian rhythm sleep disorders. Involves disruption of the body’s natural sleep cycle. Common examples include jet lag (traveling quickly across numerous time zones) and sleep problems associated with shift work. Other examples: delayed sleep phase disorder, in which people go to bed and wake up at least two hours later than is desired, and advanced phase sleep disorder, in which people fall asleep and wake up several hours earlier than is desired.

  • Parasomnias. Disorders that involve abnormal behavioral or physiological events during sleep. They involve partial arousal or interference with sleep stage transition. Examples include:

    • Arousal disorders. Disorders that involve partial arousal, such as sleepwalking and night terrors, which are characterized by sudden arousal from sleep and increased pulse and breathing rate. They occur during the first third of the sleep cycle.

    • Sleep-wake transition disorders. Disorders that interfere with sleep stage transition. Examples are sleep talking, nocturnal leg cramps, sleep starts (sudden contraction in a leg, sometimes an arm or the head, at the start of sleep) and rhythmic movement disorder (consists of recurrent head banging, head rolling and body rocking).

    • Disorders associated with rapid eye movement (REM) sleep. Some examples are nightmares (frightening dreams that occur during REM sleep and are associated with increased pulse and rate of breathing, profuse sweating and arousal) and REM sleep behavior disorder (patients act out dreams that are vivid, intense, action-packed and violent).

    • Other parasomnias. These include teeth grinding (bruxism), bedwetting (enuresis) and sudden infant death syndrome (SIDS).

  • Sleep disorders associated with medical or psychiatric conditions. They include:

    • Sleep disorders associated with psychiatric conditions. Anxiety, depression, psychosis and many other psychiatric disorders can result in excessive sleepiness or insomnia.

    • Sleep disorders associated with neurological disorders. Common examples include headaches, dementia (progressive loss of intellectual function) and Parkinson’s disease.

    • Sleep disorders associated with other medical disorders. Common examples include alcoholism, peptic ulcers, gastroesophageal reflux disease (GERD), asthma, hay fever, chronic obstructive pulmonary disease (COPD), chronic fatigue syndrome and chronic pain (e.g., fibromyalgia).

  • Proposed sleep disorders. Sleep problems for which there is insufficient information to establish them as distinct disorders. Common examples include:

    • Short sleepers. People who sleep less than 75 percent of the sleep time typically required for their age group, but who experience no negative impacts.

    • Long sleepers. People who routinely sleep more than 10 hours a night.

    • Fragmentary myoclonus. Brief, involuntary jerks or twists during sleep.

    • Sleep hyperhydrosis. Night sweats.

Potential causes of sleep disorders

Sleep disorders may be caused by a variety of factors, which may include:

  • Food and drink. Foods and drinks that contain caffeine, such as coffee, soft drinks and chocolate, can cause difficulties in falling asleep. Alcohol use can also interfere with sleeping. Although drinking alcohol can induce sleep, it can also cause people to wake prematurely.

  • Medications. Many medications interfere with sleep, such as certain antidepressants, blood pressure medications and over-the-counter cold medications. Even medications that are sedating, such as benzodiazepines and opioids, can have a negative impact on sleep.

  • Medical conditions. Many medical conditions, such as asthma, allergic rhinitis (hay fever) or peptic ulcers, can interfere with sleep.

  • Psychiatric conditions. Some mental health conditions, such as anxiety disorders and depression, can result in insomnia or hypersomnia (excessive sleepiness). Sleep disorders can also precipitate these conditions.

  • Aging. Many people over the age of 65 experience sleep problems. This may be due to medical problems more commonly encountered in the geriatric population, changes in sleep architecture that occur with aging, or medication use.

  • Life stresses. Short-term (transient) insomnia can be caused by life stresses, such as a new baby, job change or loss, death of a loved one or illness.

  • Environmental factors. Poor sleeping environments, such as those with excessive light or noise, may interfere with sleep.

  • Lifestyle factors. People who work the night shift sometimes experience sleep problems because it interferes with the biological urge to sleep during nighttime hours. Jet lag and heavy smoking can also interfere with sleep.

  • Poor sleep habits. Individuals who nap excessively during daytime hours, go to bed too early or spend excessive time awake in bed may experience sleep problems.

The cause of many sleep disorders, such as narcolepsy, is unknown (idiopathic).

Signs and symptoms of sleep disorders

The signs and symptoms vary among sleep disorders. Some common signs and symptoms of dyssomnias include difficulty falling asleep and excessive daytime drowsiness. Some signs and symptoms of parasomnias include abnormal behaviors that occur during sleep, such as walking, head banging and head rolling. Signs and symptoms of sleep disorders that are caused by medical or psychiatric conditions vary and may include difficulty falling asleep or irritability.

InsomniaDifficulty falling asleep

Difficulty staying asleep

Waking up feeling tired, even after a full night’s sleep
Sleep apneaBreathing that stops during sleep

Choking or gasping during sleep

Loud snoring
HypersomniaRecurrent episodes of daytime sleepiness or prolonged nighttime sleep


Decreased energy
NarcolepsySudden episodes of loss of muscle function (cataplexy)

Sleep paralysis (temporary inability to talk or move when falling asleep or waking up)

Hypnagogic hallucinations (vivid, often frightening dream-like experience)
Circadian rhythm sleep disordersDifficulty falling and staying asleep and/or late night insomnia

Lack of energy in the morning

Increase of energy/mood in the evening
NightmaresAbrupt awakening from sleep, usually later in the sleep period

Memory of a frightening dream

Little confusion or disorientation upon waking
Night terrorsAbrupt awakening from sleep, usually earlier in the sleep period

No memory of episode

Confusion or disorientation upon waking

Diagnosis methods for sleep disorders

Some sleep disorders may not be diagnosed for years. People may not realize that their symptoms can be attributed to a sleep disorder. A physical examination will be performed to determine if there is a medical cause for the problem. A medical history, which may include the patient’s medications and a psychiatric history, will also be taken. Patients may be given a neurological examination if a neurological cause is suspected.

Patients may be asked questions regarding sleep patterns and symptoms experienced during waking hours. Family members or sleep partners may be asked to describe sleep patterns and behavior of patients. Patients may also be asked questions regarding lifestyle habits, such as smoking or the use of alcohol or caffeine. A sleep diary detailing sleep times and patterns may help discussions with a physician or sleep specialist.

Sleep disorders can sometimes be diagnosed by identifying medications, medical or neurological conditions, psychiatric disorders or other factors that may be causing sleep problems. In other cases, patients may be referred to a sleep center where sleep patterns are analyzed in depth by health professionals who specialize in sleep disorders. Common tests that are performed to diagnose sleep disorders include:

  • Sleep questionnaire. The Epworth Sleepiness Scale uses questions to measure the likelihood of dozing in certain circumstances, such as while sitting and reading.

  • Polysomnogram (sleep study). Painless test conducted overnight while patients are sleeping. Electrodes placed on the face and scalp before sleep monitor electrical activity of the brain (electroencephalogram), heart (electrocardiogram), movements of the muscles (electromyogram) and eye movements (electro-oculogram). These are measured as patients move through the different stages of sleep.

  • Multiple sleep latency test (MSLT). Conducted in a similar method as a polysomnogram, but performed during daytime hours. This test is conducted when patients are asked to nap during the day. It may be used to diagnose narcolepsy by determining how quickly a person falls asleep during regular waking hours.

  • Repeated test of sustained wakefulness (RTSW). This test measures how long it takes to fall asleep by challenging the ability to stay awake. During the test, patients are placed in a quiet room with dim lighting and asked to stay awake. It is also used to diagnose narcolepsy.

Treatment and prevention of sleep disorders

Treatment of sleep disorders varies depending on the cause of the disorder. Underlying medical, neurological and psychiatric conditions may be treated if they are determined to be the cause of sleep disorders.

Some types of disorders can be treated or prevented by making lifestyle changes, including:

  • Avoid caffeine and alcohol. Foods and drinks that contain caffeine, such as coffee, soft drinks and chocolate, should be avoided in the afternoon and evening. Alcohol speeds the onset of sleep but increases waking during the later half of the night.

  • Avoid eating or drinking too close to bedtime. This can interrupt sleep. Also, avoid foods that may cause heartburn, such as tomato products and spicy foods. Lying down worsens heartburn and makes falling asleep more difficult.

  • Avoid smoking. Cigarettes contain nicotine, which has been linked to difficulty falling asleep and problems awakening. Also, when smokers fall asleep, they experience nicotine withdrawal, which may cause them to awaken.

  • Maintain a healthy body weight. Many cases of sleep apnea (slowed or stopped breathing during sleep) occur among overweight or obese people. Weight loss can alleviate or eliminate the symptoms.

  • Exercise. Exercising 20 to 30 minutes or more a day often helps people sleep, although exercising too soon before bedtime can cause difficulties falling asleep.

  • Find the right temperature for sleeping. Extreme temperatures can disrupt sleep.

  • Get proper light exposure. Too little exposure to sunlight during the day can cause sleep problems at night. Bedrooms should be kept dark so light does not interfere with sleep.

  • Control noise. Environmental noise can be minimized with ear plugs, rugs, heavy curtains or drapes or double-pane windows.

  • Get a proper mattress. Mattress quality can affect the quality of sleep.

  • Use the bed only for sleep and sex (not for reading or television viewing).

  • Get into bed only when tired.

  • Maintain consistent sleep and wake times.

  • Avoid or regulate nap times. Daytime naps may interfere with nighttime sleeping. Avoid naps or restrict nap times to 20 or 30 minutes.

  • Practice relaxation techniques before bedtime. These may include hot baths, gentle music, meditation or prayer.

Medications are sometimes prescribed to treat sleep disorders. They include:

  • Dopamine agonists. Medications that mimic dopamine, a neurotransmitter (brain chemical) essential to thought, motivation, short-term memory and some emotions. They are commonly used to treat Parkinson’s disease, a chronic degenerative disease of the central nervous system (CNS). Dopamine agonists may also be used to treat restless legs syndrome (sleep disorder characterized by unpleasant sensations in the legs) and periodic limb movement disorder (characterized by periodic episodes of repetitive jerking and kicking during sleep).
  • Benzodiazepines. Medications that help slow down the CNS. They help suppress rapid eye movement (REM) sleep and limit arousal. They may be prescribed to treat parasomnias (disorders that involve partial arousal or interference with sleep stage transition) or teeth grinding (bruxism).

  • Non-benzodiazepine hypnotics. Like benzodiazepines, these drugs appear to work by binding to receptors in the brain that cause sedation.

  • Opioids (narcotic painkillers). May be used to treat restless legs syndrome, although they may be habit-forming.

  • Anticonvulsants. Medications primarily used to prevent seizures. They work by inhibiting arousal. They may be prescribed to treat restless legs syndrome, periodic limb movement disorder and insomnia related to bipolar disorder. The U.S. Food and Drug Administration (FDA) has advised that anticonvulsants may increase the risk of suicidal thinking in some patients and all people being treated with them should be monitored closely for unusual changes in behavior.

  • Stimulants. Medications that act on the CNS to produce excitation, alertness and wakefulness. They may be used to treat narcolepsy.

  • Antidepressants. Medications primarily used to prevent or treat depression, anxiety and problems with obsession. They are not indicated for the treatment of insomnia. Patients should be aware that a physician may need to adjust the dosage or change medications to achieve the best results with minimal side effects. The FDA has advised that antidepressants may increase the risk of suicidal thinking in some patients and all people being treated with them should be monitored closely for unusual changes in behavior.

    In addition, there are many over-the-counter (OTC) sleeping pills or herbal supplements (e.g., chamomile, valerian) that claim to promote sleep and are available at pharmacies and other stores. However, health experts generally recommend avoiding the use of OTC sleeping pills, especially for long periods of time, because they may have undesired side effects (e.g., dizziness, prolonged drowsiness), tend to lose their effectiveness over time and may interact with other medications being taken by the patient. The use of herbal supplements has yet to be fully studied for safety or effectiveness in the treatment of insomnia.

Other techniques that may be used to treat sleep disorders include:

  • Relaxation therapy. Methods such as progressive muscle relaxation, deep breathing techniques, imagery and self-hypnosis may help some people overcome sleep disorders.

  • Chronotherapy. This form of behavioral modification involves adjustments to the sleep schedule.

  • Light therapy. Adjustments to lighting, such as turning on bright lights in the morning and dimming lights in the evening, may alter internal circadian rhythms.

  • Cognitive behavioral therapy (CBT). This may help patients identify thoughts and behaviors that contribute to sleep problems.

  • Continuous positive airway pressure (CPAP). Device used to treat sleep apnea. It involves wearing a mask over the nose that blows air into the throat at a pressure level appropriate for the patient. It keeps the throat open during sleep and prevents airway restriction.

In addition, patients with conditions such as narcolepsy may benefit from attending support groups.

Questions for your doctor about sleep disorders

Preparing questions in advance can help patients have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions about sleep disorders:

  1. I sometimes have trouble falling asleep. Is this normal, or do I have a sleep disorder?

  2. Are sleep disorders a normal part of the aging process?

  3. What type of sleep disorder do I have?

  4. What is causing my sleep disorder?

  5. What are some of the most common symptoms of sleep disorders?

  6. How can I determine whether I have sleep apnea?

  7. Should I consult a sleep center to determine the cause of my sleep disorder?

  8. How soon after beginning treatment will I see improvement in my symptoms?

  9. Can I become addicted to medication for sleep disorders such as insomnia? Are there any side effects?

  10. How can I prevent relapse of my sleep disorder?
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