Nightmares

A nightmare is a vivid, extended, disturbing dream that usually involves threat to survival, security or self esteem and wakes the sleeper, who then becomes alert quickly and recalls the content clearly.

Occasional nightmares are universal, especially in childhood.

Definition of nightmare disorder. Repeated occurrences of extended, extremely dysphoric and well remembered dreams, usually involving efforts to avoid threats to survival, security or physical integrity, that generally occur in the second half of the main sleep period. On awakening the person rapidly becomes oriented and alert.

The disturbance causes distress or impairment (mood, sleep resistance, fear of sleep, fatigue, poor concentration, behavioural problems), and is not attributable to a substance or medical condition. Severity: mild (less than once a week on average), moderate (once or more a week but not nightly), severe (nightly).

Classification

• Idiopathic nightmare disorder.
• Posttraumatic nightmares (replicative, replaying the trauma, or symbolic), which are a core symptom of posttraumatic stress disorder and acute stress disorder.
• Nightmares associated with other mental disorders (depression, anxiety, borderline personality disorder, schizophrenia).
• Nightmares caused by drugs, substances or withdrawal.
• Nightmares in medical and sleep disorders (sleep apnoea, Parkinson disease and Lewy body disease, febrile illness, heart failure).
• Childhood nightmares (a normal developmental feature from age 3 years, peaking at 6 to 10 years).

Epidemiology. Occasional nightmares occur in most adults. Weekly nightmares affect about 2 to 6% of adults, and nightly nightmares affect 1 to 2%. Nightmares occur in 50 to 80% of people with posttraumatic stress disorder. They are more common in women and in people with insomnia, psychiatric illness and a history of trauma.

Mechanisms. Nightmares arise mainly in REM sleep, when emotional memory processing and amygdala activity are high and noradrenergic tone is raised in people with trauma. Failed fear extinction, heightened arousal, and nightmare distress (an acquired fear of sleep) maintain the cycle. REM rebound after withdrawal of REM suppressing agents (alcohol, antidepressants, benzodiazepines, cannabis) causes vivid dreams and nightmares.

Key distinctions. A scream in the first third of the night with no recall and inconsolable confusion suggests a non-REM arousal (night terror). Complex movements, vocalisation and enacting a dream in a middle aged or older adult suggest REM sleep behaviour disorder. A sudden wake with fear, palpitations and no dream content suggests nocturnal panic. Stereotyped events with tongue bite or incontinence suggest seizures.

History

• The event: timing in the night (first or second half), content, whether the person awakens and is oriented, ability to describe the dream, associated movement, vocalisation, sweating and palpitations, and frequency (nights each week, nights each month).
• Impact: fear of sleep, delaying bedtime, daytime fatigue, low mood, avoidance of sleep, irritability, work and relationship strain, and suicidal thoughts.
• Trauma history: combat, accident, assault, disaster, medical illness, childhood abuse, bereavement, and symptoms of posttraumatic stress disorder (intrusions, avoidance, hypervigilance, negative mood).
• Psychiatric history: depression, anxiety, panic, psychosis, borderline personality disorder, and substance use.
• Sleep history: insomnia, snoring and witnessed apnoeas, restless legs, sleep schedule, shift work, and parasomnias (sleepwalking, night terrors, acting out dreams).
• Medical history: Parkinson disease, dementia, heart failure, asthma, thyroid disease, migraine, epilepsy, fever, pain and sleep apnoea.
• Drugs: beta blockers (propranolol and other lipophilic agents), clonidine, methyldopa, reserpine, levodopa, dopamine agonists (pramipexole, ropinirole), amantadine, SSRIs and venlafaxine, bupropion, varenicline, corticosteroids, montelukast, donepezil, statins, antiepileptics, antimalarials (mefloquine), efavirenz, and anticholinergics. Recent starting, dose increase or stopping.
• Substances: alcohol (and recent cessation), cannabis, opioids, benzodiazepines, stimulants, nicotine replacement and caffeine.
• Childhood: age, recent stress, fears, screen content, bullying, family conflict, illness, abuse and safeguarding concerns.
• Family history of sleep disorders and psychiatric illness.

Examination

• Vital signs, weight, body mass index, neck circumference, and oxygen saturation.
• Upper airway, cardiorespiratory and neurological examination (parkinsonism, tremor, rigidity, cognition).
• Mental state: mood, anxiety, intrusions, dissociation, psychosis and suicidal thoughts.
• Bedside tests: PHQ-9, GAD-7, PCL-5 (PTSD Checklist for DSM-5, 20 items scored 0 to 80, a cut off of 31 to 33 suggests posttraumatic stress disorder), Insomnia Severity Index, Epworth Sleepiness Scale, STOP-BANG, and the Nightmare Frequency Questionnaire or Nightmare Distress Questionnaire.
• Two week sleep and nightmare diary with timing, content, distress rating and substances.

Red flags

• Suicidal ideation, self harm, or hopelessness related to nightmares.
• Acting out dreams with injury to the sleeper or bed partner (REM sleep behaviour disorder, which can herald Parkinson disease, Lewy body dementia or multiple system atrophy).
• Nocturnal events with tongue bite, incontinence, stereotyped movements or post event confusion (seizures).
• Sleep apnoea features with daytime sleepiness, hypertension or morning headache.
• Recent trauma with acute stress symptoms, dissociation, or ongoing abuse or violence.
• Alcohol or benzodiazepine withdrawal (tremor, sweating, hallucinations, seizures).
• Psychosis, mania, or severe depression.
• New neurological symptoms (tremor, anosmia, constipation, falls) in a middle aged or older adult.
• Child with sudden severe nightmares and behaviour change, sexualised play, injuries, or safeguarding concern.
• Recent start of a new drug, particularly beta blockers, varenicline, levodopa or dopamine agonists.

Special groups

• Children: nightmares are common and benign when occasional. Assess fear, bedtime routine, screens, stress and safeguarding. Use age specific approaches.
• Pregnancy: nightmares increase in the third trimester, and in postpartum depression and posttraumatic stress disorder. Avoid prazosin unless benefit is clear.
• Older adults: consider drugs, Lewy body disease, REM sleep behaviour disorder, delirium and depression.
• Military, refugee and survivor populations: high prevalence of posttraumatic nightmares, with substance misuse and suicide risk.
• Region specific: culturally shaped interpretations of dreams and spirit attacks, sleep paralysis syndromes, trauma after conflict, and use of khat and alcohol.

Nightmare disorder and related psychiatric causes

• Idiopathic nightmare disorder.
• Posttraumatic stress disorder and acute stress disorder.
• Major depressive disorder and bipolar disorder.
• Anxiety disorders and panic disorder with nocturnal attacks.
• Borderline personality disorder and dissociative disorders.
• Schizophrenia spectrum disorders.
• Substance use disorders and withdrawal.

Other parasomnias and nocturnal events

• Non-REM arousal disorders: sleep terrors, sleepwalking and confusional arousals.
• REM sleep behaviour disorder.
• Isolated sleep paralysis with hypnagogic hallucinations.
• Nocturnal panic attacks.
• Sleep related epilepsy and nocturnal frontal lobe seizures.
• Sleep related hallucinations and exploding head syndrome.
• Sleep related dissociative disorder.
• Nocturnal choking, gastro-oesophageal reflux and laryngospasm.

Sleep disorders and medical causes

• Obstructive sleep apnoea and sleep related hypoxia.
• Narcolepsy (vivid dreams, sleep paralysis).
• Insomnia with REM rebound.
• Parkinson disease, Lewy body dementia and multiple system atrophy.
• Heart failure, COPD and nocturnal hypoxia.
• Febrile illness and delirium.
• Hyperthyroidism and hypoglycaemia (nocturnal).
• Migraine and cluster headache.
• Chronic pain.

Drug and substance related

• Beta blockers (lipophilic), clonidine, methyldopa and reserpine.
• Levodopa, dopamine agonists and amantadine.
• SSRIs, venlafaxine, bupropion, mirtazapine and varenicline.
• Corticosteroids, montelukast, donepezil and statins.
• Antiepileptics, mefloquine and efavirenz.
• Withdrawal from alcohol, benzodiazepines, antidepressants, cannabis and opioids (REM rebound).
• Alcohol and recreational drug use.

Step 1. Clinical diagnosis. Nightmare disorder is diagnosed from the history of recurrent awakenings with detailed recall and rapid orientation, with distress or impairment, after exclusion of drugs, substances and medical causes. Ask the patient or a bed partner about movements, vocalisation, snoring and apnoeas. Use a 2 week nightmare diary.

Step 2. Screen for trauma and psychiatric disorders. Screen for posttraumatic stress disorder (PC-PTSD-5, a score of 3 or more is positive, then PCL-5), depression (PHQ-9), anxiety (GAD-7), suicidality, alcohol (AUDIT-C), drugs and psychosis. Nightmares are a marker of suicide risk even after adjustment for depression, so ask directly.

Step 3. First line tests (only as indicated by history)

• Full blood count, glucose, urea, creatinine, electrolytes, thyroid stimulating hormone and liver tests.
• Urine drug screen if substance use is suspected.
• Review of all drugs and their dates of starting or changing.

Step 4. Targeted tests

• Polysomnography with video and extended electroencephalogram montage for suspected REM sleep behaviour disorder (REM sleep without atonia), nocturnal seizures, parasomnia with injury, sleep apnoea, or treatment resistant nightmares. Nightmares are usually not recorded in a single night.
• Home sleep apnoea test or overnight oximetry if snoring, obesity or witnessed apnoeas are present.
• Electroencephalogram (sleep deprived) and MRI brain for seizure features or neurological signs.
• Cognitive testing and neurological assessment (smell testing, orthostatic blood pressure) in older adults with REM sleep behaviour disorder.
• Safeguarding assessment for children with new severe symptoms.

Interpretation. A normal investigation is expected in idiopathic and posttraumatic nightmares. Polysomnography is mainly used to exclude other disorders. Treat comorbid sleep apnoea and posttraumatic stress disorder, because they reduce nightmare frequency when controlled.

Limits. Retrospective nightmare reports are inaccurate. Questionnaire scores screen and do not diagnose. Drug effects can be delayed by weeks.

Immediate. Reassure the patient that nightmares are common and treatable, and assess suicide risk. Review all drugs and stop or change an offending drug when safe. Advise a regular schedule, avoidance of alcohol, and a calming bedtime routine.

Non pharmacological treatment (first line for nightmare disorder)

• Imagery rehearsal therapy: the patient writes down a nightmare, changes the story or ending in any way they like, and rehearses the new version for 10 to 20 minutes each day while awake. Usually 3 to 6 weekly group or individual sessions, with benefit in about 60 to 70% of patients and lasting for months. Safe in posttraumatic stress disorder.
• Cognitive behavioural therapy for insomnia (sleep restriction used cautiously, stimulus control), because insomnia and nightmares reinforce each other.
• Exposure, relaxation and rescripting therapy, lucid dreaming therapy, and eye movement desensitisation and reprocessing.
• Trauma focused psychological therapy (prolonged exposure, cognitive processing therapy) for posttraumatic stress disorder, which reduces nightmares in most patients.
• Sleep hygiene: regular sleep and wake times, avoid alcohol, heavy meals and screens near bedtime, keep the bedroom dark and cool.
• Children: bedtime routine, reassurance, comfort objects, a night light, discussion and drawing of the dream, rescripting with a happy ending, limits on frightening media, and treatment of anxiety. Drugs are not used.

Pharmacological treatment (for severe, trauma related or treatment resistant nightmares, with psychological therapy)

• Prazosin 1 mg orally at bedtime, increased every 3 days by 1 to 2 mg to a usual 3 to 15 mg (maximum 20 mg), in divided doses (a bedtime dose with a smaller morning dose can be used). Check for first dose hypotension and syncope (give the first dose at bedtime with the patient in bed, and monitor postural blood pressure), and avoid with phosphodiesterase 5 inhibitors and other alpha blockers. Evidence is mixed, with some large studies showing no benefit over placebo, so review benefit at 4 to 6 weeks and stop if no clear gain. Reduce doses in older adults and in hepatic impairment.
• Doxazosin 1 mg at night, increased weekly to 4 to 16 mg, as an alternative with once daily dosing.
• Clonidine 0.1 mg orally at bedtime, increased to 0.2 to 0.3 mg (limited evidence; monitor for hypotension, bradycardia and rebound hypertension on stopping).
• Trazodone 25 to 50 mg at night increased to 100 mg, and mirtazapine 7.5 to 15 mg at night when depression or insomnia coexist (limited evidence).
• Cyproheptadine 4 mg orally at night, increased to 8 to 12 mg (limited evidence; sedation and anticholinergic effects), and nabilone 0.5 mg at night increased to 1 to 3 mg for refractory posttraumatic nightmares under specialist direction (limited evidence; psychiatric adverse effects).
• Posttraumatic stress disorder drug treatment: sertraline 50 mg daily increasing to 200 mg, paroxetine 20 mg increasing to 50 mg daily, or venlafaxine modified release 75 mg increasing to 225 mg, which treat the underlying disorder.
• Avoid benzodiazepines (they do not treat nightmares, impair trauma recovery, and carry dependence risk), and avoid quetiapine and other antipsychotics as routine treatment.

Treatment of the cause

• Drug induced nightmares: reduce the dose, change to a hydrophilic beta blocker (atenolol, nadolol) or another class, delay the dose to the morning, or stop. Do not stop beta blockers, antiepileptics, dopaminergic drugs or antidepressants abruptly.
• Withdrawal: manage alcohol, benzodiazepine and antidepressant withdrawal with a slow taper (for alcohol, chlordiazepoxide 15 to 30 mg every 6 hours reducing over 5 to 7 days with thiamine 100 mg daily). Nightmares from REM rebound usually settle in 1 to 4 weeks.
• Obstructive sleep apnoea: continuous positive airway pressure (auto titrating 4 to 20 cmH2O), which reduces nightmares in posttraumatic stress disorder with apnoea.
• REM sleep behaviour disorder: make the bedroom safe (remove sharp objects, pad the floor, separate beds), melatonin 3 mg at night increased to 6 to 12 mg, or clonazepam 0.25 mg at night increased to 0.5 to 2 mg (avoid in sleep apnoea, dementia, falls), and refer to neurology.
• Depression, anxiety and substance use: treat with psychological therapy and SSRIs.
• Parkinson disease: review the timing of dopaminergic drugs.

Special populations

• Pregnancy and breastfeeding: psychological treatment first. Avoid prazosin unless benefit is clear, and avoid benzodiazepines in late pregnancy.
• Older adults: look for drugs and REM sleep behaviour disorder. Start prazosin at 0.5 mg and monitor falls and postural blood pressure.
• Kidney and liver impairment: lowest effective doses.
• Children and adolescents: psychological approaches only. Specialist trauma focused therapy for posttraumatic stress disorder.

Monitoring. Nightmare frequency and distress (diary, Nightmare Frequency Questionnaire, PCL-5), sleep quality, mood, suicidal thoughts, blood pressure and postural symptoms if prazosin is used, drug adherence and adverse effects. Review at 4 to 6 weeks and again at 3 months.

Referral and escalation. Mental health services for posttraumatic stress disorder, suicidality, psychosis and severe depression. Sleep medicine for polysomnography when REM sleep behaviour disorder, seizures, parasomnia with injury or sleep apnoea is suspected. Neurology for REM sleep behaviour disorder, epilepsy and neurodegenerative disease. Child and adolescent mental health services and safeguarding teams for children. Addiction services for dependence.

Admission criteria. Rarely needed. Consider for acute suicidal risk, severe withdrawal, or injury due to violent sleep behaviour.

Discharge and follow up. Provide a written explanation and a rescripting guide, with review in 4 to 6 weeks. Safety net advice: return for thoughts of suicide or self harm, injury during sleep, events with tongue bite or incontinence, daytime sleepiness while driving, new tremor or movement problems, or worsening nightmares after a drug change.