Parasomnias Explained: Sleepwalking, Sleep Paralysis, Night Terrors and What Helps

Sleep is supposed to be a quiet, restorative state, but for millions of people it comes with unsettling extras: walking around the house without waking, screaming in the night, waking up unable to move or acting out vivid dreams. These events are called parasomnias, and they are far more common than most people realise. They can be frightening for the person experiencing them and for family members who witness them. They can also be dangerous, leading to falls, injuries and disturbed relationships. The good news is that most parasomnias have identifiable triggers and respond well to practical changes and, when needed, medical treatment. This guide explains the main types, what causes them, how to keep everyone safe, which medicines can trigger or treat them and when to see a sleep specialist.

What Are Parasomnias?

Parasomnias are unwanted physical events, behaviours or experiences that occur while falling asleep, during sleep or on waking. They happen when parts of the brain are partially awake while others remain asleep, so the person is in a blurred state between sleeping and waking. They fall into two main groups depending on the stage of sleep in which they occur.

• Non-REM parasomnias arise from deep, slow-wave sleep, mostly in the first third of the night. Examples are sleepwalking, confusional arousals, sleep terrors and sleep-related eating.
• REM parasomnias occur during dreaming sleep, more often in the second half of the night. They include nightmares, sleep paralysis and REM sleep behaviour disorder.

Sleepwalking (Somnambulism)

Sleepwalking involves getting out of bed and moving around, sometimes performing complex activities such as dressing, cooking, opening doors or even driving, while not fully conscious. Eyes are often open with a glassy stare, and the person may mumble or respond oddly to questions. Episodes usually last a few minutes to half an hour, and the person typically remembers nothing afterwards.

Around one in six children sleepwalk at some point, usually between ages four and twelve, and most outgrow it. About four per cent of adults sleepwalk, and it tends to run in families. If you want a deeper look, read what causes sleepwalking.

Common triggers

• Sleep deprivation and irregular sleep schedules
• Stress and anxiety
• Alcohol and recreational drugs
• Fever or illness
• Untreated sleep apnoea and restless legs, which cause repeated partial arousals
• A full bladder, noise or pain disturbing deep sleep
• Certain medicines, including some sleeping tablets, antipsychotics and antidepressants

Sleep (Night) Terrors and Confusional Arousals

Night terrors typically affect children aged three to seven. The child suddenly sits up, screams or cries, looks terrified, sweats and has a racing heart, yet cannot be comforted and does not recall the event in the morning. They differ from nightmares, which are scary dreams the person wakes from and remembers. Confusional arousals are milder episodes in which the person wakes in a disoriented state, sometimes with slurred speech, and then goes back to sleep. Adults can also experience these, particularly with sleep deprivation, shift work or alcohol.

Sleep Paralysis

Sleep paralysis happens when you become aware but cannot move or speak for seconds to a couple of minutes, usually while falling asleep or waking up. During REM sleep the brain temporarily paralyses most muscles to prevent you acting out dreams. In sleep paralysis, awareness returns before this paralysis lifts. Many people also experience vivid hallucinations, such as a presence in the room, pressure on the chest or shadowy figures, along with intense fear. Although terrifying, it is harmless.

Roughly one in five people experiences sleep paralysis at least once. It is more likely with sleep deprivation, irregular sleep schedules, sleeping on the back, stress, anxiety and narcolepsy. See symptoms of sleep paralysis for more detail.

REM Sleep Behaviour Disorder (RBD)

In RBD, the normal muscle paralysis of REM sleep is incomplete, so people physically act out their dreams by shouting, punching, kicking or falling out of bed. Injuries to the person or bed partner are common. RBD mainly affects men over 50 and can be an early warning sign of neurodegenerative conditions such as Parkinson’s disease or Lewy body dementia, sometimes years before other symptoms. Anyone who suspects RBD should see a sleep specialist, because it needs an overnight sleep study for diagnosis and long-term follow-up.

Nightmares and Nocturnal Panic

Nightmares are vivid, distressing dreams that wake you and leave you anxious. Frequent nightmares often accompany stress, trauma, depression or certain medicines. Night-time panic attacks cause sudden terror and a racing heart on waking, without a dream. Read anxiety attack while sleeping for how to tell them apart. Treatments include imagery rehearsal therapy for recurrent nightmares and prazosin in specific cases such as post-traumatic stress disorder.

Parasomnias Compared

Medicines That Can Trigger Parasomnias

Several prescription medicines can provoke abnormal sleep behaviours. Sedative-hypnotics known as Z-drugs, including zopiclone, zolpidem and eszopiclone, carry a specific warning about complex sleep behaviours, such as sleepwalking, sleep-eating, making phone calls or driving while not fully awake, with no memory afterwards. Risk rises with higher doses, alcohol and combining with other sedatives. If this happens, stop the medicine and contact your doctor promptly. Antipsychotics, some antidepressants, sodium oxybate and certain blood pressure medicines can also contribute. Learn more in insomnia medicines and how they work, sedative medicines and safe use and sleeping pill strengths and dosage guide.

Keeping Everyone Safe at Night

Safety is the first priority for any parasomnia involving movement.

• Lock external doors and windows, and consider alarms or door chimes.
• Move the bed to the ground floor if possible and fit stair gates.
• Clear the bedroom of sharp objects, clutter and trip hazards, and pad hard corners.
• Keep car keys, medicines and weapons locked away.
• Do not shake or shout at someone mid-episode. Gently guide them back to bed instead, since forced waking can cause confusion or aggression.
• If a partner is at risk of injury from RBD, consider separate beds until treatment takes effect.

Practical Steps to Reduce Episodes

1. Protect sleep time. Sleep deprivation is the most common trigger. Keep a regular bedtime and wake time, and aim for seven to nine hours for adults. Read the effects of sleep deprivation on the brain.
2. Limit alcohol and caffeine, particularly in the evening.
3. Manage stress with relaxation, exercise and therapy. See does anxiety affect sleep?
4. Treat underlying sleep disorders such as apnoea and restless legs.
5. Empty your bladder before bed and keep the room dark, cool and quiet.
6. Try scheduled awakenings for children with frequent night terrors: waking the child gently about 15 minutes before the usual event time for a week or two can break the cycle.
7. Follow good sleep hygiene. See sleep hygiene tips and natural sleep aids.

Managing Sleep Paralysis Episodes

• Remind yourself that it is temporary and harmless. Fighting it tends to increase fear.
• Focus on moving a small body part, such as a finger or toe, or on controlled breathing.
• Avoid sleeping flat on your back if episodes cluster there.
• Keep a regular sleep routine and manage anxiety.
• See a doctor if episodes are frequent, disturb sleep or come with sudden daytime sleep attacks, which may suggest narcolepsy.

When to See a Doctor or Sleep Specialist

Seek medical advice if episodes happen often, involve injury or risk of injury, begin in adulthood, include violent or sexual behaviour, occur alongside loud snoring and breathing pauses, or you suspect medicines are involved. A specialist may arrange an overnight sleep study (polysomnography) with video, which records brain activity, breathing, movement and muscle tone. Treatments range from behavioural changes and cognitive behavioural therapy to treating apnoea, adjusting medicines and, in some cases, medicines such as clonazepam or melatonin for RBD.

Frequently Asked Questions

Is it dangerous to wake a sleepwalker?

It is not harmful, but it may cause confusion or fright. Gently guide them back to bed whenever possible.

Can sleepwalkers do harm?

Mostly they injure themselves through falls and collisions, but rarely behaviour can be aggressive. Safety measures and medical review are important.

Do children grow out of night terrors?

Most do by their early teens, and episodes become less frequent as sleep matures.

Is sleep paralysis a sign of mental illness?

No. It is common in healthy people and is linked to sleep disruption rather than psychiatric illness.

Can stress cause parasomnias?

Yes. Stress and anxiety increase arousals and can trigger or worsen episodes.

A Parent’s Guide to Children’s Parasomnias

Night terrors, sleepwalking and confusional arousals are very common in childhood because young children spend more of the night in deep sleep. They are rarely a sign of psychological problems. Keep a consistent bedtime, since overtiredness is the most frequent trigger, and make sure the child’s bedroom is safe, with a stair gate and secured windows. During an episode, stay calm, make sure the child cannot get hurt and avoid trying to wake or talk them out of it. Reassure them in the morning without describing the event in frightening detail. Seek medical advice if episodes become more frequent, last longer than about thirty minutes, occur several times a night, happen in teenagers or adults for the first time, or are accompanied by loud snoring, pauses in breathing or daytime sleepiness. Treating enlarged tonsils or adenoids that cause breathing disruption often stops episodes completely.

How Parasomnias Are Diagnosed

Most diagnoses begin with a detailed story. A doctor will ask when episodes occur during the night, how long they last, what happens, whether the person remembers anything, who has witnessed them and what medicines, alcohol and drugs are used. A partner’s description is extremely valuable, and a short phone video can help. A sleep diary kept over two weeks shows patterns of sleep time, naps, caffeine, alcohol and stress. Overnight polysomnography is reserved for suspected REM sleep behaviour disorder, violent or injurious episodes, atypical features or suspected seizures, because nocturnal epilepsy can look like a parasomnia. Blood tests may check for conditions such as thyroid disease and iron deficiency, which is associated with restless legs.

Keep a Simple Sleep and Event Diary

• Record bedtime, wake time and any naps.
• Note alcohol, caffeine, medicines and large late meals.
• Describe each event: time, duration, what happened and who witnessed it.
• Score stress and mood from one to ten each evening.
• Review the diary after two weeks to spot triggers and share it with your doctor.

Common Myths About Parasomnias

• “Sleepwalkers are acting out their dreams.” Sleepwalking comes from deep non-dreaming sleep, whereas acting out dreams is RBD.
• “Sleepwalking means something is wrong psychologically.” Most cases are linked to sleep disruption and genetics.
• “You should never wake a sleepwalker.” It is safe, but gentle redirection is usually kinder and less confusing.
• “Sleep paralysis is caused by spirits or something supernatural.” It is a well-understood overlap between REM and wakefulness.
• “Sleeping pills always help these conditions.” Some sleep medicines can make parasomnias worse, so use only as advised.

Final Thoughts

Parasomnias are alarming but usually manageable. Protect your sleep, avoid triggers such as alcohol and sleep loss, make the bedroom safe and review any medicines that could be responsible. If episodes persist, cause injury or begin later in life, a sleep specialist can find the cause and guide treatment.

Disclaimer: This article is for general information only and is not medical advice. Always consult a doctor or pharmacist before taking any medicine.