Somnambulism is the medical term for sleepwalking, a sleep disorder in which a person gets up and moves around, sometimes performing complex actions, while remaining asleep. About 7% of people experience it at least once in their lifetime, and it is far more common in children than adults. Episodes arise from the deepest stage of non-dreaming sleep, typically in the first few hours of the night, and the person almost never remembers them afterward.
What Happens in the Brain During an Episode
Sleepwalking occurs during stage 3 non-REM sleep, also called slow-wave sleep. This is the deepest phase of the sleep cycle and concentrates in the first third of the night, which is why most episodes happen within a few hours of falling asleep. During this stage, overall brain metabolism drops sharply compared to waking life. The areas responsible for planning, decision-making, and self-awareness (particularly the prefrontal cortex and a midline region involved in consciousness called the precuneus) become especially quiet.
What makes sleepwalking unusual is that the brain is not fully asleep or fully awake. Functional imaging studies show that during an episode, some brain networks display patterns typical of deep sleep while others show activity resembling wakefulness. Researchers have found decreased connectivity in the brain’s posterior regions at slow-wave frequencies, alongside increased connectivity in frontal-to-back networks at frequencies associated with alertness. In practical terms, the parts of the brain that control movement can “wake up” enough to walk and interact with the environment, while the parts responsible for awareness and memory remain asleep. This is why sleepwalkers can navigate rooms and even carry on brief conversations, yet have no conscious experience of doing so.
Notably, these differences in brain activity aren’t limited to episodes themselves. People prone to sleepwalking show reduced slow-wave activity in motor and sensory-related brain areas even during nights when no episode occurs, and even during REM sleep and waking rest. This suggests their brains have a baseline tendency toward incomplete transitions between sleep states.
What a Sleepwalking Episode Looks Like
Episodes range from sitting up in bed and looking around to walking through the house, opening doors, or rearranging objects. Some people perform surprisingly complex actions: getting dressed, preparing food, or even leaving the house. The eyes are typically open, and the person may appear confused or glassy-eyed. They can sometimes respond to questions with short, mumbled answers, but their responses rarely make full sense.
A single episode can last anywhere from a few minutes to about an hour. Afterward, the person either returns to bed on their own or can be gently guided back. Upon waking the next morning, there is complete amnesia for the event. If woken during an episode, the person is usually disoriented and confused for several minutes.
Who Gets It and Why
Sleepwalking peaks in childhood. In any given year, roughly 5% of children experience it, most often between ages 4 and 8. The prevalence drops significantly by the teen years, and only about 1.5% of adults sleepwalk in a given year. The condition runs strongly in families. If one parent has a history of sleepwalking, a child’s risk increases substantially, and the risk climbs further if both parents were affected.
Several triggers can provoke episodes or make them more frequent:
- Sleep deprivation. Not getting enough sleep increases the proportion of deep slow-wave sleep the brain tries to recover, creating more opportunity for episodes.
- Stress and anxiety. Emotional distress fragments sleep architecture and can trigger arousals from deep sleep.
- Alcohol. Drinking disrupts normal sleep cycling and can increase slow-wave sleep early in the night.
- Fever. Especially in children, elevated body temperature can destabilize sleep stages.
- Schedule disruptions. Jet lag, shift work, or an irregular bedtime can throw off the timing of deep sleep.
- Certain medications. Some drugs that affect the nervous system can increase the likelihood of episodes.
How It Differs From Other Sleep Disorders
Sleepwalking is sometimes confused with REM sleep behavior disorder (RBD), but the two arise from completely different sleep stages. Sleepwalking emerges from deep non-REM sleep early in the night. The person’s eyes are open, movements are calm (if clumsy), and they have no dream recall. RBD occurs during REM (dreaming) sleep, usually later in the night. People with RBD act out their dreams, often with sudden, violent movements like punching or kicking, and they can frequently recall vivid dream content when awakened.
The distinction matters because RBD in older adults is closely associated with neurodegenerative conditions like Parkinson’s disease, while childhood sleepwalking is almost always benign. When episodes involve highly repetitive, stereotyped movements or occur at unusual times, clinicians also consider whether frontal lobe seizures might be responsible, since these can mimic sleepwalking closely.
Diagnosis
In most cases, a diagnosis is made from the history alone. A bed partner or family member describes the episodes, including when in the night they happen, what the person does, and whether they remember anything. A sleep study (polysomnography) is generally unnecessary unless the episodes are unusually frequent, violent, or don’t fit the typical pattern. When a sleep study is performed, it can confirm that episodes arise from deep non-REM sleep and rule out seizure activity or other sleep disorders.
Treatment and Management
Occasional sleepwalking, particularly in children, usually doesn’t require treatment. Most children outgrow it by adolescence. Treatment becomes worth pursuing when episodes are frequent enough to disrupt sleep, risk injury, or cause significant distress.
The first line of approach targets whatever is feeding the episodes. That means prioritizing consistent, adequate sleep; reducing stress through relaxation techniques or, for children, open conversations about worries; and reviewing any medications that might be contributing. If episodes follow a predictable schedule, a technique called anticipatory awakening can help: gently waking the person about 15 minutes before they typically sleepwalk, keeping them awake briefly, then letting them fall back asleep. This resets the sleep cycle and can prevent the episode from occurring.
Hypnotherapy with a practitioner experienced in sleep disorders has shown benefit for some people. The goal is to reach a state of deep relaxation that can modify the unwanted arousal patterns during sleep. For severe or dangerous cases that don’t respond to behavioral strategies, medications that calm the nervous system or certain antidepressants may be prescribed to suppress the deep-sleep arousals that trigger episodes.
Keeping the Environment Safe
Because sleepwalkers are unaware of their surroundings and can’t assess danger, making the home safer is one of the most practical steps you can take. Lock windows and exterior doors, and consider placing the key out of easy reach. If a child sleepwalks, avoid bunk beds. Remove sharp objects and tripping hazards from hallways and the bedroom. Installing a gate at the top of stairs or a bell on the bedroom door can alert household members when an episode begins. Keep the sleeping area on the ground floor if possible.
If you encounter someone sleepwalking, avoid shaking them awake aggressively. This rarely helps and often leaves them frightened and disoriented. Instead, gently guide them back to bed. They’ll usually comply without resistance and will have no memory of it in the morning.