Sleepwalking: Causes, Triggers, and When to Worry

Sleepwalking Is a Mix of Being Asleep and Awake

Sleepwalking, or somnambulism, happens during the deepest stage of non-REM sleep, usually within the first couple of hours after falling asleep. It's classified as a parasomnia — an "arousal disorder" where part of the brain partially wakes up while the rest stays in deep sleep. That's why a sleepwalker can get up, move around, sometimes talk or perform routine tasks, all while their eyes look open and blank and they don't respond normally to being spoken to. Contrary to the popular idea, sleepwalkers aren't acting out a dream. Dreaming happens during REM sleep, and sleepwalking happens during non-REM slow-wave sleep, a completely different stage with a different mechanism.

The brain's transition between deep sleep and lighter sleep or waking is normally smooth. In people who sleepwalk, something interrupts that transition — the motor and behavioral parts of the brain partially activate while the parts responsible for conscious awareness and memory stay offline. That's also why sleepwalkers almost never remember the episode afterward, even a fairly involved one.

What Triggers an Episode

Sleepwalking has a strong genetic component — a family history is the single biggest risk factor, and researchers have found a child has roughly a 45% chance of sleepwalking if one parent did, rising to around 60% if both parents did. But genetics set up the susceptibility; specific triggers are usually what sets off an actual episode on a given night.

Why It's So Much More Common in Kids

Sleepwalking shows up most often in children between about 4 and 8 years old, with somewhere around 15% to 30% of children sleepwalking at least once. The reason comes down to sleep architecture: children spend a larger proportion of the night in slow-wave (deep) sleep than adults do, which is exactly the stage sleepwalking arises from. As the nervous system matures through adolescence, that proportion of deep sleep naturally decreases, and most children stop sleepwalking on their own well before adulthood — usually by puberty, though there's no fixed cutoff.

Adults sleepwalk too, just less often — somewhere around 1% to 4% of adults have an episode at some point. Adult sleepwalking is more likely to be either a continuation of a childhood pattern that never fully went away, or new-onset sleepwalking tied to one of the specific triggers above, particularly sleep apnea, medication, or a major stressor. That distinction matters for what to do about it, which is covered further down.

What a Sleepwalking Episode Actually Looks Like

Episodes vary widely in how involved they get. On the mild end, someone might just sit up in bed, look around with a blank expression, and lie back down without ever leaving the bed. On the more involved end, sleepwalkers have been documented walking through the house, opening and closing doors, getting dressed, eating, rearranging furniture, and in rare cases doing things like driving a car or unlocking a door and going outside. The activities tend to be routine and familiar to the person — the brain seems to run on autopilot through things it already knows how to do, rather than generating anything new.

Movements are usually described as clumsy or gangly rather than smoothly coordinated. Sleepwalkers may mumble or speak, but what comes out is often nonsensical or unresponsive to questions. An episode can last anywhere from under a minute to half an hour or more, and it typically ends with the person either returning to bed on their own or being gently guided back by someone else — with no memory of any of it the next morning.

Sleepwalk-Proofing a Home

Because sleepwalkers move through the world without normal awareness of their surroundings, the main real risk from sleepwalking is injury, not the sleepwalking itself. A few practical changes make a meaningful difference for anyone in the household who sleepwalks regularly, especially children.

The Signs That Go Beyond "They'll Grow Out of It"

The common, and usually accurate, advice for childhood sleepwalking is that it's benign and will be outgrown. But there are specific situations where it's worth an actual medical evaluation rather than waiting: episodes that happen several times a week, episodes that involve leaving the house or attempting to drive, any injury during an episode, violent or aggressive behavior during sleep, and sleepwalking that starts for the first time in adulthood. A doctor can also help rule out other conditions that can look similar, like nighttime seizures, and can screen for an underlying trigger like sleep apnea that might be driving frequent episodes.

A sleep specialist may recommend an overnight sleep study (polysomnography) for frequent or concerning episodes, which records brain waves, breathing, and movement to confirm the diagnosis and check for an underlying sleep disorder feeding into it. Treatment, when it's needed at all, usually starts with addressing an identifiable trigger — treating sleep apnea, adjusting a medication, or improving sleep habits — before medication is considered.

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