Parasomnias
also known as sleepwalking, night terrors, REM behavior disorder, and related
Medically reviewed by the Shrinkopedia editorial team, led by Shariq Refai, MD, MBA, FAPA.
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Parasomnias are undesirable events that occur during sleep, entering sleep, or emerging from sleep. They are divided by which sleep stage they arise from: NREM parasomnias (sleepwalking, sleep terrors, confusional arousals, sleep-related eating) arise from deep NREM sleep, and REM parasomnias (REM sleep behavior disorder, nightmare disorder, recurrent isolated sleep paralysis) arise from REM sleep. Most childhood NREM parasomnias resolve with age. REM sleep behavior disorder in adults deserves special attention because it is now recognized as a prodromal marker of alpha-synucleinopathies (Parkinson's disease, dementia with Lewy bodies, multiple system atrophy), with conversion rates over 80 percent over 10-15 years in some studies. Safety-oriented management, distinguishing parasomnias from nocturnal seizures, and, in REM behavior disorder, planning for long-term neurological follow-up all matter.
What research says
Prevalence. - NREM parasomnias in children: sleepwalking 10-15 percent, sleep terrors 1-6 percent at some point in childhood - NREM parasomnias in adults: 1-4 percent - RBD in adults: approximately 1 percent - Nightmare disorder: 2-8 percent chronic
Course of NREM parasomnias. Most childhood cases resolve by adolescence. Adult onset or persistence into adulthood is less common and may warrant evaluation.
Course of RBD. Idiopathic RBD has approximately 80+ percent conversion to a defined alpha-synucleinopathy over 10-15 years in longitudinal studies. This is one of the strongest known clinical prodromal markers.
Treatment evidence. - Sleep hygiene and safety measures: universal - Clonazepam: standard treatment for RBD, effective but with tolerance, dependence, and cognitive concerns - Melatonin (high-dose): increasingly used for RBD, better side-effect profile - For NREM parasomnias: address triggers, safety measures, occasionally benzodiazepines or other medications for severe cases - CBT-I for nightmare disorder and secondary insomnia - Image rehearsal therapy for chronic nightmares - Prazosin for PTSD-related nightmares (mixed evidence)
Questions people ask
Are night terrors the same as nightmares?
No. Night terrors arise from NREM sleep, involve dramatic autonomic arousal and amnesia for the event, and typically occur early in the night. Nightmares arise from REM sleep, involve remembered dream content, and typically occur later in the night. Very different clinical pictures.
Should I wake someone who is sleepwalking?
Gently guide them back to bed rather than trying to wake them abruptly. Waking abruptly can produce confusion and agitation. Redirecting to bed is usually possible and safer.
Are parasomnias dangerous?
Injury from parasomnias is a real concern, particularly in adult sleepwalking and RBD. Safety measures (locked doors, safe environment, protecting bed partners) matter.
What is REM sleep behavior disorder?
Loss of the normal muscle paralysis of REM sleep, allowing the person to act out dreams. Can be violent. In adults, idiopathic RBD is a strong marker of subsequent alpha-synucleinopathy (Parkinson's disease, dementia with Lewy bodies, multiple system atrophy).
Does RBD mean I'll get Parkinson's?
Longitudinal studies show conversion rates of 80+ percent over 10-15 years for idiopathic RBD to a defined alpha-synucleinopathy. This is one of the strongest known clinical predictors. Not universal but a real risk. Neurology follow-up matters.
How is RBD treated?
Safety measures (protecting bed partner and person from injury), and pharmacotherapy: melatonin (3-15 mg at bedtime, increasingly preferred as first-line) or clonazepam (traditional first-line, effective but with concerns).
Can antidepressants cause RBD?
Yes, SSRIs, SNRIs, and mirtazapine can produce RBD-like symptoms. This may resolve with medication change. Some cases may reflect unmasking of underlying vulnerability.
Should children with sleepwalking be evaluated?
Most childhood sleepwalking is benign and resolves with age. Evaluation is warranted if injuries occur, if it persists into adolescence or adulthood, or if atypical features are present.
How do I know if events are seizures or parasomnias?
Sometimes difficult. Stereotyped movements, post-ictal confusion, and other epilepsy features suggest seizures. Video-EEG monitoring may be needed for definitive diagnosis. Frontal lobe epilepsy is particularly likely to be confused with parasomnia.
Can medications trigger parasomnias?
What is image rehearsal therapy?
A CBT technique for nightmare disorder. In waking hours, the person mentally rehearses their nightmares with changed endings. Reduces nightmare frequency and distress in evidence-based studies.
Should I see a psychiatrist or a sleep specialist?
Sleep specialist for parasomnia evaluation and diagnosis. Neurologist for RBD given the neurodegeneration connection. Psychiatrist for co-occurring conditions (PTSD, depression) affecting sleep. Coordinated care often helps.
What parasomnias are
Under ICSD-3, parasomnias are classified by the sleep stage from which they arise:
NREM parasomnias (arising from deep, slow-wave NREM sleep, typically in the first third of the night): - Confusional arousals: sudden brief awakening with confusion, without full alertness, without leaving bed. Common in children. - Sleepwalking (somnambulism): complex motor behaviors during sleep, ranging from simple walking to elaborate activities. Person appears awake but is not fully conscious. Amnesia for the event. - Sleep terrors (night terrors): sudden awakening with intense fear, autonomic arousal (sweating, tachycardia), often screaming, difficulty being comforted. Amnesia for the event. Different from nightmares. - Sleep-related eating disorder: eating during partial arousal from sleep, often with amnesia. - Sexsomnia: sexual behaviors during sleep.
REM parasomnias (arising from REM sleep, typically later in the night): - REM sleep behavior disorder (RBD): loss of the normal REM sleep muscle atonia, allowing the person to act out dreams. Can be violent (kicking, punching, jumping out of bed). Very important condition; see below. - Nightmare disorder: recurrent distressing dreams causing awakenings and dysfunction. - Recurrent isolated sleep paralysis: sleep paralysis without narcolepsy.
Other parasomnias: - Exploding head syndrome: sudden loud imagined noise at sleep-wake transition. Benign, though can be alarming. - Sleep-related hallucinations: hypnagogic and hypnopompic hallucinations. See narcolepsy for related discussion. - Bedwetting (nocturnal enuresis): various patterns.
REM sleep behavior disorder: the important adult parasomnia
RBD deserves detailed discussion because of its major clinical significance beyond the sleep symptoms themselves.
Clinical picture. The person acts out their dreams. Muscle atonia that normally accompanies REM sleep is lost or incomplete. Behaviors range from talking or arm movements to violent thrashing, punching, kicking, or jumping out of bed. Injuries to self or bed partner are common. The person is often experiencing an unpleasant or aggressive dream that they act out. Complete recall of the dream is often available on waking.
Age and demographics. Most commonly develops after age 50. Male predominance (approximately 80-90 percent).
Diagnostic requirements. Requires polysomnography demonstrating loss of REM atonia (REM sleep without atonia, RSWA) plus history of dream enactment.
Alpha-synucleinopathy connection. This is the crucial insight. Idiopathic RBD is now recognized as a prodromal marker of alpha-synucleinopathies: - Parkinson's disease - Dementia with Lewy bodies (DLB) - Multiple system atrophy (MSA)
Longitudinal studies (Postuma, Iranzo, Schenck and colleagues) demonstrate that 80+ percent of patients with idiopathic RBD will develop one of these conditions over 10-15 years. This is one of the strongest known clinical predictors of subsequent neurological disease.
Clinical implications. Patients with newly diagnosed RBD should: - Have neurology follow-up (movement disorders specialist ideally) - Consider participation in prodromal Parkinson's research studies when available - Be informed of the association (this is a difficult but important conversation) - Have safety measures in the bedroom - Consider treatment for the RBD itself (clonazepam or melatonin)
Not every case of dream enactment is RBD. Some patients have similar behaviors from other causes (medication effects, other sleep disorders). Careful evaluation matters.
Symptomatic RBD. RBD can also occur as a symptom of neurological disease (established Parkinson's, MSA, DLB) or medication effects (antidepressants, particularly SSRIs and SNRIs, can produce RBD-like behavior). This differs from idiopathic RBD in prognosis.
RBD triggered by antidepressants. SSRIs, SNRIs, and mirtazapine can produce RBD-like behaviors, sometimes without the alpha-synucleinopathy risk. In some cases these represent unmasking of underlying vulnerability; in others they resolve with medication change.
What NREM parasomnias feel like
From the person's perspective. Amnesia for the event is characteristic. The person may wake up unaware anything happened, or with only fragmented sense of confusion.
From the observer's perspective. The person appears partly awake but not fully conscious. Their eyes may be open. They may be able to respond simply but not coherently. Behaviors vary: walking around, moving objects, apparent purposeful activity, eating, or (in sexsomnia) sexual activity.
Sleep terrors specifically: sudden onset with screaming, appearing terrified, autonomic arousal (rapid heartbeat, sweating, dilated pupils), inconsolable, then returning to sleep with no memory of the episode. Distinguishable from nightmares by: - Timing (early night, in NREM; nightmares late night, in REM) - Content (little or no dream recall in terrors; vivid dream memory in nightmares) - Autonomic arousal (dramatic in terrors, less so in nightmares) - Awakening (no full awakening in terrors; person wakes up from nightmares) - Consolability (difficult in terrors; possible in nightmares)
Sleepwalking: complex motor behaviors during partial NREM arousal. Person may walk around, leave the bedroom, occasionally leave the house. Can perform elaborate activities. Injury risk from environmental hazards. Amnesia for the event.
Sleep-related eating disorder: getting up to eat during sleep with amnesia. May eat unusual food combinations or non-food items. Weight gain is a common consequence.
Differential diagnosis
Nocturnal seizures. Can look very similar to parasomnias. Distinguishing features: - Stereotyped movements (same each time in seizures) - Post-episode confusion (post-ictal in seizures) - Ictal EEG changes (though nocturnal frontal lobe epilepsy can be normal on scalp EEG) - Diurnal seizures may also be present
Video-EEG monitoring may be needed. Frontal lobe epilepsy is particularly likely to be confused with parasomnia.
Nocturnal panic attacks. Anxiety symptoms with sudden awakening. Distinguishable by the specific anxiety character and absence of the parasomnia patterns.
PTSD nightmares. Trauma-related recurring dreams. Different from RBD (person wakes from PTSD nightmares; person acts out in RBD).
Nocturnal hallucinations. Various causes. Distinguishable by pattern.
Delirium. Confusion at night in medically ill patients. Distinguishable by broader delirium features.
Rhythmic movement disorder. Head banging, body rocking during sleep. Common in young children.
Restless legs syndrome / periodic limb movement disorder. Movement during sleep but not usually confused with parasomnia.
Sleep-related eating disorder secondary to zolpidem or other Z-drugs. These medications famously produce sleep-related eating and other complex behaviors in some users. Withdrawal typically resolves.
Why parasomnias happen
NREM parasomnias: emerge from incomplete arousal from deep NREM sleep. Genetic vulnerability is substantial (family aggregation is common). Triggers include: - Sleep deprivation - Stress - Fever - Medications (some hypnotics, particularly Z-drugs; also alcohol) - Sleep disorders (OSA can trigger NREM parasomnias) - Menstrual cycle in some patients
REM sleep behavior disorder: loss of REM atonia. In idiopathic RBD, this reflects prodromal alpha-synucleinopathy. In symptomatic RBD, reflects the underlying neurological disease. Medication-induced RBD reflects direct pharmacological effect.
Nightmare disorder: multifactorial. Trauma is a common contributor. Medications (particularly withdrawal from REM-suppressing agents) can trigger.
Assessment
Clinical interview about the events: - Timing (early or late night) - Nature of behaviors - Consciousness during and memory of events - Injuries - Triggers - Family history - Medications - Comorbid sleep symptoms
Bed partner information is often essential.
Diagnostic testing: - Polysomnography (PSG): not always needed for typical NREM parasomnias but essential for RBD (to demonstrate loss of REM atonia) - Video-PSG: can capture events for characterization - Video-EEG monitoring if seizures suspected
Neurological evaluation for adults with RBD or atypical presentations.
Treatment
NREM parasomnias.
- Address triggers: adequate sleep, stress reduction, avoid alcohol at bedtime, review medications, treat OSA if present
- Safety measures: door alarms, keep bedroom safe, lock windows in sleepwalkers
- Reassurance in children; most resolve
- Medications reserved for severe cases: benzodiazepines (clonazepam), TCAs, occasionally topiramate for sleep-related eating
REM sleep behavior disorder.
- Safety measures: crucial. Padded bed rails or sleeping on floor mattress, remove sharp objects, protect bed partner (separate beds may be needed for severity)
- Melatonin: 3-15 mg at bedtime. Increasingly preferred as first-line. Better side-effect profile than clonazepam.
- Clonazepam: 0.5-2 mg at bedtime. Traditional treatment. Effective but with concerns about tolerance, cognitive effects in older adults, and dependence.
- Review medications that may trigger (antidepressants, particularly SSRIs and SNRIs)
- Neurology referral for evaluation and long-term follow-up given the alpha-synucleinopathy risk
- Discussion of the alpha-synucleinopathy connection with the patient (a difficult but important conversation)
- Consider enrollment in prodromal Parkinson's research studies
Nightmare disorder.
- Address underlying conditions (PTSD, depression, sleep apnea)
- Image rehearsal therapy (IRT): rewriting nightmares in waking hours with changed endings. Evidence-based.
- CBT for nightmares
- Prazosin: sometimes used for PTSD-related nightmares. Evidence is mixed (VA studies have shown less benefit than initially hoped).
- Review medications that trigger nightmares (antidepressant withdrawal, beta blockers, others)
Recurrent isolated sleep paralysis.
- Sleep hygiene
- Address predisposing sleep deprivation
- Reassurance about the benign nature
- If related to narcolepsy, address that
Sleep-related eating disorder.
- Address triggers
- Assess for zolpidem or other Z-drug involvement (may resolve with discontinuation)
- Topiramate has some evidence
- Behavioral interventions
Sexsomnia.
- Legal considerations may apply
- Address triggers
- Sleep specialist involvement
- Sometimes clonazepam
Cultural and structural considerations
Access to sleep specialists varies. Referral for polysomnography and specialist assessment may be limited in some areas.
Legal implications in some parasomnias (particularly sexsomnia, sleep-driving, violent RBD behaviors) can involve criminal charges. Sleep medicine expert involvement matters.
Disclosure of RBD-alpha-synucleinopathy connection is a difficult conversation. Some patients want to know; some prefer not. Individualized discussion matters.
Living with parasomnias
For the person. For NREM parasomnias, addressing sleep deprivation and other triggers often produces substantial improvement. For RBD, safety measures and treatment (typically melatonin or clonazepam) allow safe sleep. Neurological follow-up over years is important. For nightmare disorder, image rehearsal therapy and addressing underlying causes both help.
For family or partners. Bed partner information is often diagnostically important. Safety measures matter, particularly in RBD where injury to bed partner is real. Understanding that the person is not conscious during NREM parasomnias helps reduce interpersonal conflict about the behavior.
Sources
- American Academy of Sleep Medicine. International Classification of Sleep Disorders, Third Edition (ICSD-3). 2014.
- Schenck CH, Bundlie SR, Mahowald MW. Delayed emergence of a parkinsonian disorder in 38% of 29 older men initially diagnosed with idiopathic rapid eye movement sleep behaviour disorder. Neurology. 1996;46(2):388-393.
- Iranzo A, Molinuevo JL, Santamaria J, et al. Rapid-eye-movement sleep behaviour disorder as an early marker for a neurodegenerative disorder: a descriptive study. The Lancet Neurology. 2006;5(7):572-577.
- Postuma RB, Iranzo A, Hu M, et al. Risk and predictors of dementia and parkinsonism in idiopathic REM sleep behaviour disorder: a multicentre study. Brain. 2019;142(3):744-759.
- Boeve BF. REM sleep behavior disorder: updated review of the core features, the REM sleep behavior disorder-neurodegenerative disease association, evolving concepts, controversies, and future directions. Annals of the New York Academy of Sciences. 2010;1184:15-54.
- Aurora RN, Zak RS, Maganti RK, et al. Best practice guide for the treatment of REM sleep behavior disorder (RBD). Journal of Clinical Sleep Medicine. 2010;6(1):85-95.
- McGrane IR, Leung JG, St Louis EK, Boeve BF. Melatonin therapy for REM sleep behavior disorder: a critical review of evidence. Sleep Medicine. 2015;16(1):19-26.
- Mahowald MW, Schenck CH. NREM sleep parasomnias. Neurologic Clinics. 2005;23(4):1077-1106.
- Krakow B, Zadra A. Clinical management of chronic nightmares: imagery rehearsal therapy. Behavioral Sleep Medicine. 2006;4(1):45-70.
- Raskind MA, Peskind ER, Chow B, et al. Trial of prazosin for post-traumatic stress disorder in military veterans. New England Journal of Medicine. 2018;378(6):507-517.
- Winkelman JW. Clinical and polysomnographic features of sleep-related eating disorder. Journal of Clinical Psychiatry. 1998;59(1):14-19.
- Pressman MR. Common misconceptions about sleepwalking and other parasomnias. Sleep Medicine Clinics. 2011;6(4):xiii-xiv.
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