Sleep Disorders - Description

Sleep disorders are divided into two major categories. One category consists of disorders in which a person has trouble falling asleep or staying asleep. This category also includes disorders in which a person may fall asleep at inappropriate times. Conditions of these kinds are called dyssomnias. A second category of sleep disorders includes those in which people experience physical events while they are sleeping. Nightmares and sleepwalking are examples of these disorders. Conditions of this type are called parasomnias.

The following are some examples of each type of sleep disorder:

Dyssomnias

• Insomnia. Insomnia (see insomnia entry) is perhaps the most common of all sleep disorders. About 35 percent of all adults in the United States experience insomnia during any given year. People with insomnia have trouble falling asleep. Often people with this disorder worry or become anxious about not being able to sleep, which can make the problem even worse. Insomnia may begin at any time in a person's life. It tends to be most common in young adulthood and middle age.
• Hypersomnia. Hypersomnia is a condition in which a person is excessively sleepy during normal waking hours. The person may often fall asleep for lengthy periods during the day, even if he or she has had a good night's sleep. In some cases, patients have difficulty waking up in the morning. They may seem confused or angry when they awaken. About 5 to 10 percent of people who seek help for sleep disorders have hypersomnia. The condition is most common in young adults between the ages of fifteen to thirty.
• Narcolepsy. Narcolepsy is characterized by sleep attacks over which patients have no control. They may fall asleep suddenly with no warning. The sleep attack may last a few minutes or a few hours. The number of attacks patients experience can vary. People with narcolepsy usually feel refreshed after awakening from a sleep attack but they may become sleepy again a few hours later and experience another attack.

Three other conditions are often associated with narcolepsy: cataplexy, hallucinations, and sleep paralysis. Cataplexy is the sudden collapse of a person's muscles. The person may become completely limp and fall to the ground. A person may also experience hallucinations. Hallucinations are sounds and sights that a person experiences that do not exist in the real world. Sleep paralysis occurs when a person is just falling asleep or just waking up. The person may want to move, but is unable to do so for a few moments.

• Sleep apnea. Sleep apnea (pronounced AP-nee-uh) is a condition in which a person actually stops breathing for ten seconds or more. The most common symptom of sleep apnea is very loud snoring. Patients with this condition alternate between periods of snoring or gasping and periods of silence.
• Circadian rhythm sleep disorders. The term circadian (pronounced sir-CAYD-ee-uhn) rhythm refers to the usual cycle of activities, such as waking and sleeping that is common to any form of life. Most people are accustomed to falling asleep after it gets dark out and waking up when it gets light. In certain conditions, this pattern can be disrupted. A person may fall asleep as the sun comes up and wake up as the sun goes down. An example of a circadian sleep disorder is jet lag. People who fly suddenly across many time zones may have their sleep patterns disrupted. It may take a few days before those patterns return to normal.

Parasomnias

• Nightmare disorder. Nightmare disorder is a condition in which a person is awakened from sleep by frightening dreams. Upon awakening, the person is usually fully awake. About 10 to 50 percent of children between the ages of three and five have nightmares. The condition is most likely to occur in children and adults who are under severe stress.
• Sleep terror disorder. Sleep terror disorder occurs when a patient awakens suddenly crying or screaming. The patient may display other symptoms, such as sweating and shaking. Upon awakening, the patient may be confused or disoriented for several minutes. He or she may not remember the dream that caused the event. Sleep may return in a matter of minutes. Sleep terror disorder is common in children four to twelve years of age. The condition tends to disappear as one grows older. Less than one percent of adults have the disorder.
• Sleepwalking disorder. Sleepwalking disorder is also called somnambulism (pronounced suhm-NAHM-byoo-LIHZ-uhm). The condition is characterized by a variety of behaviors, of which walking is only one. Sleepwalkers may also eat, use the bathroom, unlock doors, and carry on conversations. If awakened, sleepwalkers may be disoriented. They may have no memory of their sleepwalking experience. About 10 to 30 percent of children have at least one sleepwalking experience. The occurrence among adults is much lower, amounting to about 1 to 5 percent of all adults.

A few sleep disorders are related to some physical or mental disorder. The three conditions that fall into his category include:

• Sleep disorders related to mental disorders. Many types of mental illness can cause sleep disorders. People who have severe mental illness, for example, may develop chronic (long-lasting) insomnia.
• Sleep disorders due to physical conditions. Physical illnesses such as Parkinson's disease (see Parkinson's disease entry), encephalitis (see encephalitis entry), brain disease, and hyperthyroidism may cause sleep disorders.
• Substance-induced sleep disorders. The use of certain types of drugs can lead to sleep disorders. The most common of these drugs are alcohol and caffeine. Certain types of medications can also cause sleep disorders. Antihistamines, steroids, and medicines used to treat asthma are examples.