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Classification & external resources
ICD-10 F51.3
ICD-9 307.4

Sleepwalking (also called somnambulism or noctambulism[1]), under the larger category of parasomnias or sleep disorders where the sufferer engages in activities that are normally associated with wakefulness while he or she is asleep or in a sleeplike state. Sleepwalking is usually defined by, or involves the person affected apparently shifting from his or her prior sleeping position and moving around and performing normal actions as if awake (cleaning, walking and other activities). Sleepwalkers are not conscious of their actions on a level where memory of the sleepwalking episode can be recalled, and because of this, unless the sleepwalker is woken or aroused by someone else, this sleep disorder can go unnoticed. Sleepwalking is more commonly experienced in people with high levels of stress, anxiety or psychological factors and in people with genetic factors (family history) or sometimes a combination of both.

A common misconception is that sleepwalking is an individual acting out the physical movements within a dream, but in fact sleepwalking occurs earlier on in the night when rapid eye movement (REM), or the "dream stage" of sleep, has not yet occurred.



A majority of people move their legs while sleeping; however, sleepwalking occurs when both legs move in synchronization, which is much less common.

Sleepwalking can affect people of any age. It generally occurs when an individual awakes suddenly from slow wave sleep (SWS, sometimes referred to as "deep sleep"); causing the sleepwalking episode.[citation needed] In children and young adults, up to 25% of the night is spent in SWS.[citation needed] However this decreases as the person ages until none can be measured in the geriatric individual.[citation needed] For this reason, children and young adults (or anyone else with a high amount of SWS), are more likely to be woken up and, for the same reasons, they are witnessed to have many more episodes than the older individuals.[citation needed]


This causes REM atonia, a state in which the motor neurons are not stimulated and thus the body's muscles don't move. Lack of such REM atonia causes REM Behavior Disorder; sufferers act out the movements occurring in their dreams.


  • 18% of the world's population is prone to sleepwalking.[2][3]
  • Somewhere between 1% and 16.7% of U.S. children sleepwalk, and juveniles are seen to be those more prone to the activity.[citation needed]
  • One study showed that the highest prevalence of sleepwalking was 16.7% for children of 11 to 12 years of age.[citation needed]
  • Males are seen to be more likely to sleepwalk than females.[2]

Activities such as eating, bathing, urinating, dressing, or even driving cars,[4] whistling, engaging in sexual intercourse,[4] and committing murder[5][6][7] have been reported or claimed to have occurred during sleepwalking. Contrary to popular belief, most cases of sleepwalking do not consist of walking around (without the conscious knowledge of the subject). Most cases of somnambulism occur when the person is awakened (something or someone disturbs their SWS), the person may sit up, look around and immediately go back to sleep. But these kinds of incidences are rarely noticed or reported unless recorded in a sleep clinic.[citation needed]

Sleepwalkers engage in their activities with their eyes open so they can navigate their surroundings, not with their eyes closed and their arms outstretched, as often parodied in cartoons and films.[citation needed] The victims' eyes may have a glazed or empty appearance and if questioned, the subject will be slow to answer and will be unable to respond in an intelligible manner.[dubious]


Sleepwalkers are more likely to endanger themselves than anyone else[citation needed]. When sleepwalkers are a danger to themselves or others (for example, when climbing up or down steps or trying to use a potentially dangerous tool such as a stove or a knife), steering them away from the danger and back to bed is advisable. It has even been reported that people have fallen out of windows, and died, or were injured as a result[8]. Sleepwalking should not be confused with psychosis.

Sleepwalking has in rare cases been used as a defense (sometimes successfully) against charges of murder.

Main article: Sleepwalking murder

Dealing with sleepwalkers

Often the best way to deal with a sleepwalker safely is to direct the person back to the bed. However, the person may continue getting up until he or she has accomplished the task that prompted the sleepwalking in the first place. For instance, if a sleepwalker is cleaning - a common sleepwalking activity - assisting in the cleaning may help to end the episode. Telling the person "It looks like you have cleaned it all up" can help him or her to feel as though the "necessary" task has been accomplished. As sleepwalkers do not tend to remember anything said or done while sleepwalking, there is no need to worry about embarrassment to you or the individual afterward.

Somnambulists are highly suggestible. Anything they hear or see may trigger another behavior. Often something said by a person or even on a television will cause the sleepwalker to engage in the activity mentioned, provided it is one to which he or she is accustomed to hearing about or doing. If the sleepwalker is also talking, it may be helpful to ask what he or she is trying to accomplish. Ask very simple questions that can be answered in short, simple replies. If asked a question that requires a long answer or explanation, the sleepwalker is unlikely to respond coherently. Talking during sleepwalking varies from person to person and may not always be useful in dealing with a sleepwalker. Because sleepwalkers are unaware of their present surroundings, they may divulge information that they would otherwise keep secret. They may also exhibit behaviors which would be considered embarrassing, such as urinating in inappropriate places, trying to eat invisible foods, cleaning invisible counters, or even trying to bathe or engage in sexual intercourse.

In art and culture

The 19th Century German chemist and metaphysician Baron Karl Ludwig von Reichenbach made extensive studies of sleepwalkers, and used his discoveries to formulate his theory of the Odic force.

Sleepwalking has been found as a theme in many dramatic works. It is a major plot element in the classic silent German Expressionist film Das Kabinett des Dr. Kaligari (English title: The Cabinet of Dr. Caligari) 1920. In Shakespeare's Macbeth, Lady Macbeth sleepwalks because of her overwhelming guilt and insanity. Italian composer Vincenzo Bellini's opera La Sonnambula is named after its heroine, a sleepwalker. In Dario Argento's Phenomena (1985), the protagonist, Jennifer Corvino (Jennifer Connelly), witnesses a murder while sleepwalking. In the film adaptation of Silent Hill, the protagonist's daughter suffers from sleepwalking. Also, a recent ep released by a horror rock band called the Batteries is titled Somnambulism.

Legal defense

In 1846, Albert Tirrell was found not guilty of murder and arson, arguing that if he did do it, he was sleepwalking at the time, the first successful acquittal using a sleepwalking defense in American legal history.[9]

Kenneth Parks, a 23-year-old, drove his car 15 miles to his in-laws house in May 1987. There, he attacked his father-in-law leaving him unconscious and stabbed his mother-in-law, killing her. He then went to the police station saying, “I think I have killed some people”. He was bloody and his hand was heavily beat up. Parks was unable to recount anything about the murder, and he had no motives for committing them. He was unemployed, and stressed. He went to sleep that night thinking about how he was going to visit his in-laws the next day with his wife to tell them about his financial and gambling problems. After a year, he was found not guilty of murder or attempted murder. There was an appeal, but his acquittal was upheld. He was not even sentenced to time in a mental ward since “noninsane automatism”, (ie. Sleepwalking) is not legally viewed as a mental disorder. [10]

See also


  1. ^ That is, somn-ambulism, sleep-walking, walking in one's sleep, or noct-ambulism, night-walking, walking in the night.
  2. ^ a b Sleep Walking Overview, Causes and Treatment
  3. ^ Sleepwalking at h2g2
  4. ^ a b Rachel Nowak. "Sleepwalking woman had sex with strangers", New Scientist, 2004-10-15. Retrieved on 2007-04-30. 
  5. ^
  6. ^
  7. ^
  8. ^,1518,502518,00.html?Punchline=Tada German Sleepwalker Steps Out of 4th-Floor Window
  9. ^ Kappman (ed), Edward W. (1994). Great American Trials. Detroit, MI: Visible Ink Press, 101–104. ISBN 0-8103-9134-1. 
  10. ^ Man Acquitted Of Sleepwalking Murder Running For School Trustee In Durham
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Sleepwalking". A list of authors is available in Wikipedia.
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