Medical expert of the article
New publications
Sleepwalking (somnambulism)
Last reviewed: 05.07.2025
All iLive content is medically reviewed or fact checked to ensure as much factual accuracy as possible.
We have strict sourcing guidelines and only link to reputable media sites, academic research institutions and, whenever possible, medically peer reviewed studies. Note that the numbers in parentheses ([1], [2], etc.) are clickable links to these studies.
If you feel that any of our content is inaccurate, out-of-date, or otherwise questionable, please select it and press Ctrl + Enter.
Sleepwalking, or somnambulism, is sitting, walking, or other complex behavior during sleep, usually with the eyes open but without awareness of what is happening. Sleepwalking is typical of late childhood and puberty, and occurs with incomplete awakening from stages III and IV of slow (non-REM) sleep. The likelihood of somnambulism increases with previous deprivation and poor sleep hygiene; family cases have been described. Mumbling in sleep, causing injuries on obstacles or on stairs are common, but there are no dreams. As a rule, patients do not remember anything.
Crimes may be committed during sleep, in which case the defense of automatism may be adequate. Since R v. Burgess (1991), sleepwalking has been considered by the courts to be an "internal factor," that is, an automatism associated with insanity.
[ Causes of sleepwalking
Sleepwalking occurs during stage 4 slow-wave sleep, rather than REM (rapid eye movement) sleep, when the body is normally motionless. Partial arousal may occur, during which complex actions, including violence, may be performed. According to Fenwick, the following factors should be considered when diagnosing sleepwalking, especially when assessing crimes that may have been committed during sleepwalking.
The following general factors are important:
- Family history: It is known that there is a genetic component to the etiology of sleepwalking.
- Childhood onset. Sleepwalking usually begins in childhood; although in a smaller number of cases it begins in adolescence.
- Late onset sleepwalking is rare. However, it can happen after a head injury. If the first episode of sleepwalking occurs at the time of the commission of a crime, then this should be approached with a fair amount of doubt.
Next, we should consider the episode more subjectively.
- Considering that sleepwalking occurs in stages 3-4 of sleep, it should occur within two hours of falling asleep.
- Upon awakening, the face should be disoriented.
- Witnesses should note inappropriate automatic behavior and disorientation upon awakening.
- There must be amnesia that extends throughout the entire period of sleepwalking.
- There may be some “trigger” factors, such as drug use, alcohol use, excessive fatigue or stress.
- If it is a sexual crime, then sexual arousal during sleep occurs only during the REM sleep phase, that is, not during sleepwalking.
- Any memories related to the period before sleepwalking should not be dream-like.
- Crimes committed while sleepwalking are not typically subject to concealment.
- Similar behavior may have been observed in previous sleepwalking episodes.
- If the crime appears unmotivated and uncharacteristic of the person, this supports the view that it was committed while sleepwalking.
Treatment of sleepwalking
Treatment is aimed at protecting against damage by using electronic alarms to wake up, a low bed, and removing obstacles from the bedroom.
People suffering from sleepwalking are advised to sleep with doors and windows locked and prescribed medications. Benzodiazepines are effective medications, especially clonazepam 0.5-2 mg orally before bedtime.