Sleepwalking is a parasomnia in which a person partially awakens from non-REM sleep and engages in motor behaviour while remaining incompletely conscious. The behaviour can range from sitting up or walking around the bedroom to more complex actions, such as moving objects, opening doors or performing familiar routines. The person's eyes may be open, but visual responsiveness and awareness can be abnormal. Sleepwalking most often occurs during deeper non-REM sleep and is especially common during childhood, with many cases becoming less frequent as maturation occurs.
Sleepwalking is best understood as a state of incomplete arousal rather than ordinary waking behaviour performed unconsciously in a simple sense. Brain regions supporting movement can become sufficiently activated to permit coordinated activity while systems responsible for full awareness, judgement and memory remain partly asleep. This dissociation explains why a sleepwalker may navigate a familiar environment yet respond poorly to questions and have little recollection afterwards. Complex behaviour does not necessarily imply conscious intention or complete awareness.
Episodes commonly occur during the first part of the night because deep non-REM sleep is more concentrated earlier in the main sleep period. Sleep deprivation can increase the pressure for deep sleep and thereby increase the probability of incomplete arousals. Irregular schedules, stress, fever, environmental disturbance and certain medications can also influence susceptibility. Obstructive sleep apnoea and other conditions that repeatedly disrupt sleep can sometimes contribute to abnormal arousals, so persistent or newly emerging sleepwalking should not automatically be regarded as an isolated behavioural phenomenon.
Sleepwalking can create safety risks because the person may encounter stairs, windows, doors, furniture, traffic or other hazards while having impaired judgement and awareness. Rarely, complex behaviour can result in substantial injury to the sleepwalker or another person. Environmental safety measures can therefore be more important than attempting to analyse the person's behaviour during the episode. Securing hazardous objects, reducing access to dangerous areas and improving the sleeping environment may be appropriate when episodes are frequent or risky.
It is generally preferable not to confront or aggressively awaken a sleepwalker. Gentle guidance back towards bed may be less disruptive than sudden forced awakening, although safety takes priority if the person is approaching an immediate hazard. If awakening occurs, the individual may appear confused and disoriented. Afterward, they may have no memory or only fragmentary memories of the event. The common idea that waking a sleepwalker is inherently dangerous is overstated, but abrupt awakening can produce temporary confusion or agitation.
Diagnosis is usually clinical and based on the observed pattern of episodes, their timing, behaviour and subsequent recall. Information from household members can be essential because the person may be unaware that episodes occur. Polysomnography may be used when the presentation is unusual, when another sleep disorder is suspected or when events need to be distinguished from nocturnal epilepsy or another condition. Video monitoring can provide useful evidence about movement patterns and responsiveness during episodes.
Childhood sleepwalking frequently resolves without specific treatment, particularly when adequate sleep and regular schedules are maintained. In adults, persistent, newly developed or dangerous sleepwalking deserves greater clinical attention because contributing factors can include medications, sleep disorders and neurological conditions. Treatment therefore begins with identifying and reducing precipitating factors rather than assuming that medication is required. When episodes are frequent or hazardous, a sleep specialist may consider further evaluation and targeted treatment.
Sleepwalking should not be confused with deliberate nighttime activity, psychogenic behaviour or simply being awake without remembering the event. Nor does it necessarily indicate a severe neurological disorder. The key characteristics are partial arousal from sleep, impaired awareness and subsequent amnesia or limited recall. The condition demonstrates that sleep and wakefulness are not always binary states: aspects of motor functioning and environmental interaction can become active while conscious awareness remains substantially reduced.
