Definition and Overview

Also known as somnipathy, sleep disorder is a number of medical conditions that affect the sleep patterns of an individual. Sleep disorders range from mild to severe, with the more serious ones enough to disrupt the mental, physical, emotional, and social aspects of an individual’s life. Insomnia is perhaps the most recognized type of sleep disorder, but the term can also refer to frequent night terrors and even teeth grinding when asleep.

To determine the presence and extent of sleep disorders, doctors can order a polysomnography or actigraphy. Polysomnography, or PSG, is a standard test that records the various biophysiological changes that occur in an individual’s body while he or she is sleeping. This test is usually performed at night when people sleep, but many hospitals or clinics can accommodate patients suffering from circadian rhythm sleep disorders and perform this test at any other time in the day when the patient would be asleep. A PSG test can accurately monitor a patient’s eye, brain, skeletal muscle activity, heart rhythms, and muscle movement during sleep.

On the other hand, an actigraphy monitors the patient’s rest and activity cycles. The patient will need to wear a small actimetry sensor, which resembles a wristwatch, while sleeping. The actimetry sensor will record the patient’s motor activity. The information collected by the device will be transferred to a computer for analysis.

There are many types of identified sleep disorders, but they fall under broadly classified categories, such as the following:

  • Dyssomnias. These disorders make it difficult for the patient to sleep or remain sleeping. The disorders under this category typically involve difficulty in initiating or maintaining slumber, excessive sleep, or any kind of disturbance that affects the timing, quality, or amount of the patient’s slumber. Insomnia and narcolepsy are among the most common dyssomnias.

  • Parasomnias. The disorders in this category involve abnormal dreams, behaviours, emotions, movements, and perceptions that the patient has while asleep. Most of the disorders under the parasomnia category are essentially partial “arousals” or waking in between NREM or REM sleep and being fully awake. Sleepwalking, night terrors, teeth grinding or bruxism, sleep-related eating disorders, and restless legs syndrome are among the most common parasomnias.

  • Circadian rhythm sleep disorders. The disorders that fall under this category affect the timing of the patient’s sleep. Individuals suffering from this type of sleep orders have trouble with sleeping and waking at “normal” times that fit their social, personal, or professional needs. Simply put, their body clocks dictate rather abnormal hours. There are two subcategories of circadian rhythm sleep disorders, intrinsic and extrinsic ones.

Cause of Condition

A wide variety of factors can affect an individual’s sleep patterns. While the root cause of these conditions varies widely, they disrupt not only the patient’s slumber but also brings about various effects on the body, mind, function, and relationship with others.

A specific cause may be hard to pinpoint, but there are some general factors that affect sleep patterns, such as:

  • Physical pains and disturbances (for example, pain from the internal organs can easily rouse a patient and make it difficult to go back to sleep)
  • Various medical conditions and problems (for example, difficulty in breathing caused by asthma can be a hindrance to normal sleep)
  • Psychiatric factors (depression or anxiety disorder can definitely affect sleep)
  • Other environmental factors (such as consumption of drugs and alcoholic substances).

Sleep disorders can also be caused by the patient’s emotions, such as anxiety over one’s job, relationships, and life status. Mild to extreme sensitivity to light, noise, and changes in temperature can also be a cause of sleep disorders.

On the other hand, chronic sleep disorders can be caused by chronic stress, depressive disorders, or chronic discomfort experienced when the patient is going to sleep. Genetics can be a factor that greatly influences one’s tendency to have sleep disorders. People who work night shifts are also at a higher risk of developing sleep disorders and altering their body clocks because the hours they work do not allow them to naturally fall asleep when their bodies need to.

The natural aging process can also contribute to sleep disorders, though experts are not absolutely certain whether it is the age that increases the risk or the combination of maintenance medication.

Key Symptoms

Sleep disorders can manifest in a wide variety of symptoms, even in seemingly innocent ways. Here are some of the more common symptoms of different sleep disorders:

  • Excessive sleepiness during the day
  • Inexplicable irritability in the daytime
  • Suddenly falling asleep while sitting and doing another activity, such as reading or watching TV
  • Difficulty in concentrating on certain tasks at home, work, or school
  • Feeling extremely sleepy and falling asleep while driving
  • Looking tired most of the time
  • Difficulty remembering things or retaining information
  • Decreased reaction or response to stimulus
  • Emotional instability
  • Needing chemical stimulation (in the form of caffeine) to stay awake
  • Snoring
  • Difficulty in breathing while sleeping
  • Difficulty in falling asleep
  • Night terrors or frequent nightmares
  • Bedwetting
  • Waking up numerous times during the night

If you observe these symptoms regularly, pay your doctor a visit.

Who to See and Type of Treatments Available

Patients suffering from sleep disorders or suspecting that they might have abnormalities in their sleep patterns should see a specialist in sleep medicine. These doctors are board certified and properly trained to deal with any type of sleep disorder thrown their way. A specialist in this field should be certified by the American Board of Sleep Medicine or such types of organizations.

The sleep medicine specialist can recommend a wide variety of treatment and management options, such as therapy, surgery, or medication. They can also refer the patient to a psychiatrist or another specialist to treat the root cause of the sleep disorder. Changes in the patient’s lifestyles might also work as an effective treatment or management option; the patient might be able to sleep properly and regularly after such changes.


  • Ancoli-Israel S, Shochat T. Insomnia in older adults. In: Kryger MH, Roth T, Dement WC, eds. Principles and Practice of Sleep Medicine. 5th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 135.
  • Juergens TM, Barczi SR. Sleep. In: Duthie EH, Katz PR, Malone ML, eds. Practice of Geriatrics. 4th ed. Philadelphia, PA: Elsevier Saunders; 2007:chap 22.
  • National Heart, Lung, and Blood Institute. How Much Sleep is Enough? Available at: Updated February 22, 2012. Accessed October 22, 2014.
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