Should I wake someone who is sleepwalking?

Contrary to popular belief, waking a sleepwalker is not dangerous — the idea that it causes harm is a myth. However, waking them can cause brief confusion or distress. The recommended approach is to gently guide them back to bed without waking them if possible, and to ensure the environment is safe. If there is immediate danger, waking them is appropriate.

Do children outgrow sleepwalking and night terrors?

Yes, in the majority of cases. Sleepwalking and sleep terrors are most common between the ages of 4 and 10 and typically resolve during adolescence as deep slow-wave sleep naturally decreases. A small proportion of children continue into adulthood, and adult-onset sleepwalking is less common but does occur, particularly under conditions of sleep deprivation or stress.

Can sleep apnea cause sleepwalking?

Yes. Sleep apnea can trigger partial arousals from slow-wave sleep that manifest as sleepwalking or other NREM parasomnias. When sleep apnea is treated effectively with CPAP, these episodes often resolve completely — even when sleepwalking had been occurring for years. This is one reason why a thorough sleep evaluation is important in adults with frequent parasomnias.

Why is REM sleep behaviour disorder such a serious diagnosis?

RBD is a significant diagnosis because, in the majority of cases, it is an early manifestation of an underlying neurodegenerative disease — particularly Parkinson's disease, Lewy body dementia, or multiple system atrophy. Studies show that 80–90% of people with idiopathic RBD develop one of these conditions within 10–15 years. Early identification allows for monitoring, lifestyle interventions, and potential participation in neuroprotective research trials.

What Are Parasomnias? | whataresleepdisorders.com

Parasomnias are a broad category of sleep disorders involving unwanted physical or experiential events that occur during sleep, at the transition into sleep, or while waking from sleep. They range from the relatively benign — occasional sleeptalking or teeth-grinding — to the potentially dangerous, such as sleepwalking on a staircase or acting out violent dreams. Understanding which type is occurring, and why, is essential to managing them safely.

What Are Parasomnias?

The word "parasomnia" combines the Greek para (alongside or abnormal) with the Latin somnus (sleep). These disorders involve abnormal movements, behaviours, emotions, perceptions, or dreams that arise from abnormal transitions between sleep states or from partial arousals.

A key feature of most parasomnias is that the person is neither fully awake nor fully asleep during the episode — they are in a hybrid state with elements of both. This explains why someone sleepwalking may navigate familiar environments, speak, or perform complex tasks while being completely unresponsive and having no memory of the event the next morning.

Parasomnias are classified based on which sleep stage they arise from:

NREM parasomnias arise from non-REM sleep (slow-wave sleep) — these are the classic "disorders of arousal"
REM parasomnias arise from REM sleep — the dreaming stage
Other parasomnias that span sleep stages or occur at sleep transitions

NREM Parasomnias: Disorders of Arousal

NREM parasomnias occur during slow-wave (deep) sleep, typically in the first third of the night. They are more common in children than adults and run strongly in families. During an episode, the person appears awake but is functionally asleep — they cannot be easily roused, do not respond appropriately to questions, and typically have complete amnesia for the episode the next morning.

Sleepwalking (Somnambulism)

Sleepwalking involves getting up from bed and walking around while remaining asleep. Episodes can be simple (sitting up, making repetitive movements) or complex — navigating the house, eating food from the kitchen, or even leaving the home. The person's eyes are open and they may avoid obstacles, but they are unresponsive to others. Sleepwalking is most common in children aged 4–8, affecting up to 17% at some point, but can persist into adulthood or begin in adulthood for the first time. In adults, sleepwalking warrants more thorough evaluation.

Sleep Terrors (Night Terrors)

Sleep terrors are episodes of apparent intense terror, usually beginning with a piercing scream, rapid heart rate, sweating, and signs of extreme agitation. The person may sit bolt upright, stare with wide, frightened eyes, and be inconsolable — but they are asleep throughout. Unlike nightmares, there is no recalled dream. The episode resolves on its own, often within minutes, and the person returns to quiet sleep with no memory of the event. Sleep terrors are distressing to witness but not harmful to the child.

Confusional Arousals

Episodes of mental confusion upon awakening from slow-wave sleep, typically occurring in the first hours of the night. The person may be disoriented, slow to respond, and appear confused or distressed. Episodes typically last minutes and resolve without full awakening. Common in young children and in adults who are chronically sleep-deprived.

Sleep-Related Eating Disorder (SRED)

A form of sleepwalking in which the person compulsively eats during the night with partial or no recall. Episodes can involve consuming unusual combinations of food or non-food substances. SRED is associated with the use of certain sleep medications (particularly zolpidem) and with other eating disorders.

REM Parasomnias

REM parasomnias occur during REM sleep — the stage of vivid dreaming — typically in the second half of the night when REM periods are longest.

REM Sleep Behaviour Disorder (RBD)

RBD is the most clinically significant REM parasomnia. In normal REM sleep, the brain actively suppresses muscle movement (REM atonia) to prevent the physical enactment of dreams. In RBD, this muscle suppression fails, causing people to physically act out their dreams — shouting, punching, kicking, or leaping from bed. The dreams are typically vivid and threatening, often involving being chased or attacked. Injuries to the person or their bed partner are common.

RBD is rare in the general population but carries critical clinical significance: it is a strong early marker for neurodegenerative disease. Approximately 80–90% of people with idiopathic RBD will eventually develop Parkinson's disease, Lewy body dementia, or multiple system atrophy — often 10–15 years after RBD onset. This makes RBD diagnosis an important opportunity for early intervention and research participation.

Nightmare Disorder

Nightmares are vivid, disturbing dreams from which the person awakens with clear recall and strong emotional distress. Occasional nightmares are universal, but nightmare disorder is diagnosed when nightmares are recurrent, cause significant distress or functional impairment, and are not better explained by medication, substances, or another mental health condition. Nightmare disorder is strongly associated with PTSD and is treated with Image Rehearsal Therapy (IRT) or prazosin.

Other Common Parasomnias

Sleep paralysis: A temporary inability to move upon waking or falling asleep, often with hallucinations. See our dedicated article for full detail.
Exploding Head Syndrome: A harmless but alarming experience of a loud bang, crash, or explosion sound perceived during the transition to sleep, sometimes with a flash of light. It is not dangerous and requires no treatment beyond reassurance.
Sleep bruxism: Repetitive teeth-grinding or jaw-clenching during sleep, which can cause dental wear, jaw pain, and headaches. Management includes dental mouth guards.
Sleep enuresis (bed-wetting): Involuntary urination during sleep, most common in children but occurring in adults with neurological or urological conditions.

Causes and Risk Factors

Parasomnias are associated with several contributing factors:

Genetics: NREM parasomnias in particular run strongly in families. Having a parent with sleepwalking significantly increases a child's risk.
Sleep deprivation and schedule disruption: Reduced slow-wave sleep leads to deeper rebound slow-wave sleep, which increases NREM parasomnia risk.
Fever or illness: Particularly in children, can trigger episodes.
Stress and anxiety: Heightened arousal increases partial awakening likelihood.
Medications: Sedative-hypnotics (particularly zolpidem), antidepressants, antipsychotics, and beta-blockers can trigger or worsen various parasomnias.
Other sleep disorders: Sleep apnea can trigger NREM parasomnias through repeated arousals; treating the apnea often resolves the sleepwalking.
Neurodegeneration: RBD specifically is strongly associated with synucleinopathies.

When to Speak With a Doctor

See a doctor about parasomnia behaviours if: the person is injuring themselves or others during episodes, episodes are occurring nightly or multiple times per week, sleepwalking is occurring outside the home or in dangerous environments, the behaviour has begun in adulthood without a prior history (especially in middle-aged or older men — this warrants RBD evaluation), or if there is significant sleep disruption or daytime impairment. Parasomnias in adults deserve thorough clinical evaluation.

Diagnosis

Most parasomnias are diagnosed primarily from history — ideally with information from both the patient and any witnesses who have observed the episodes. A doctor will ask about the timing of episodes (early vs late night), whether there is any recall, the specific behaviours involved, family history, and current medications.

An overnight polysomnography (sleep study) is particularly important when: RBD is suspected (to confirm or refute REM atonia loss), when sleep apnea may be triggering arousals, when the behaviours are violent or injurious, or when the diagnosis is clinically uncertain. Video recording of episodes at home is extremely useful to show the doctor.

Treatment and Safety Management

Treatment approach varies significantly by parasomnia type:

Safety measures: For sleepwalking and RBD, the priority is preventing injury. This means locking external doors and windows, securing potentially dangerous objects, placing a mattress on the floor, using bed alarms, and for RBD, having the bed partner sleep separately if there is injury risk.
Treating underlying causes: Addressing sleep apnea, adjusting triggering medications, or correcting sleep deprivation can substantially reduce NREM parasomnia frequency.
Clonazepam: Low-dose clonazepam is highly effective for RBD, suppressing enactment behaviours in most patients. Melatonin (high doses) is an alternative with fewer side effects, particularly useful in elderly patients.
Scheduled awakenings: For children with regular sleep terrors or sleepwalking, gently waking the child 15–30 minutes before the typical episode time can interrupt the cycle.
Reassurance: For parents of children with sleep terrors or confusional arousals, the most important intervention is understanding that these episodes, though alarming, are not harmful to the child and that most children outgrow them.

References

Howell MJ. Parasomnias: an updated review. Neurotherapeutics. 2012;9(4):753–775.
Postuma RB, et al. Idiopathic REM sleep behaviour disorder and neurodegeneration — an update. Nature Reviews Neurology. 2019;15(4):213–228.
American Academy of Sleep Medicine. International Classification of Sleep Disorders, 3rd edition. 2014.
Mahowald MW, Schenck CH. Insights from studying human sleep disorders. Nature. 2005;437(7063):1279–1285.