Sleep-related complaints are second only to complaints of pain as a cause to seek medical attention.
We classify sleep disorders broadly into three categories:
Sleep disorders are a 24-hour condition that affect the person all day, not just at night. They lead to an inferior quality of life as patients feel stressed and sleepy during the day. There are dozens of different disorders.
Only a doctor can give a medical diagnosis. Sleep diaries, actigraphy, EEGs, and polysomnograms are among the diagnostic tools employed.
The government estimates 70 million people in the United States have a sleep disorder (over 20% of the population), and that for 60% of those people the disorder is chronic. Much of the Sleepdex website is devoted to describing sleep disorders and explaining what doctors and scientists know about them. Even if you don’t have a formal disorder now, there is a good chance you will get one during your lifetime. Disorders become more common with age – both primary disorders and secondary disorders which are consequences of other health problems.
The Centers for Disease Control and Prevention says "Insufficient Sleep Is a Public Health Problem"
Insomnia is a blanket term for many phenomena. Everyone has insomnia occasionally. Some people have it often. Other have it chronically, which is not fun at all. The National Institutes of Health estimates that 60 million people in the US have it in any given year. See our section on insomnia.
One of the most dangerous disorders is apnea, a cessation of breathing during sleep. The fat buildup and loss of muscle tone from aging and obesity can allow the windpipe to collapse, preventing the flow of air to the lungs. Apnea is associated with loud snoring (although not everyone who snores has apnea) and can also occur if the neurons that control breathing malfunction during sleep. A person with apnea may struggle to breathe (with a surge in blood pressure and heart rate) for 10 seconds to more than a minute, awaken, snort or gasp then resume snoring. This cycle may be repeated hundreds of times a night. Although most sufferers will not remember these brief awakenings, they can leave the person sleepy and possibly irritable and depressed. This and the disruption of a bed partner’s sleep can cause a strain on relationships.
The type of apnea described above is called obstructive sleep apnea. Another type, though much less common is called central sleep apnea, in which the airway is not blocked but the brain fails to signal the body to breathe. Some people suffer from both types of apnea.
Apnea is associated with coronary heart disease, heart attack, high blood pressure, congestive heart failure, pulmonary hypertension, stroke, neuropsychiatric problems and mental impairment. People with severe, untreated sleep apnea are two to three times more likely to have automobile accidents than the general population. The National Center on Sleep Disorders Research estimates that sleep apnea accounts for $42 million in hospital bills yearly.
Apnea can only be diagnosed through a medical evaluation, usually an overnight study at a sleep laboratory. It is estimated that 18 million people in the US have it, although many are unaware and undiagnosed. Mild sleep apnea can often be overcome by a person losing weight, not sleeping on his or her back and/or wearing special dental or oral appliances. Severe cases may be treated with special devices such as CPAP machines worn over the nose or surgery. People with sleep apnea should never take sleeping pills or sedatives because these could prevent them from awakening enough to breathe.
Snoring can be a nuisance and can signal the very serious problems of sleep apnea and upper airway resistance. Simple snoring (without apnea) is sometimes considered to be at the mildest end of the sleep disordered breathing spectrum. Snoring is associated with the hypertension, cardiovascular disease, and diabetes. The only intervention strategy accepted at present is weight loss. More on snoring.
Narcolepsy is a disorder that makes people fall asleep often and suddenly. It affects about 0.5% of the population. Four symptoms characterize narcolepsy: (1) excessive daytime sleepiness with irresistible sleep attacks, (2) cataplexy (sudden loss of muscle tone often resulting in collapse), (3) hypnogogia (sleep paralysis), and (4) (sometimes associated with hypnogogia) hallucinogens Cataplexy is the most dramatic symptom to external observers, but it should be noted that most people with narcolepsy do not experience cataplexy.
Narcoleptics are more likely to have other sleep disorders, including like obstructive sleep apnea syndrome, periodic limb movements in sleep, and REM sleep behavior disorder. More on narcolepsy.
Restless Legs Syndrome (RLS) is an unpleasant crawling, prickling or tickling sensation in the legs and feet and the urge to walk or move them to find relief. Although not considered serious medically, RLS makes it difficult to fall asleep and stay asleep. It is estimated that 12 million people in the US have RLS.
Most people with RLS also have Periodic Limb Movement Disorder (PLMD) or repetitive movements of the toe, foot and sometimes the knee and hip during sleep. Sufferers may be unaware of sleep disturbances but their bed partners often are not so lucky.
These conditions are associated with other medical conditions such as iron-deficiency anemia, pregnancy and diabetes. There is evidence that blood iron levels are correlated with RLS. People experiencing them should consult a health care professional. Severe RLS is most common among the elderly but symptoms can develop at any age.
Not surprisingly, people with ADHD often have sleep disorders. The symptoms of ADHD - inattention and hyperactivity - play out differently. People with high scores on inattention tend to need more sleep. Hyperactive ADHD sufferers tend to need less sleep.