Insomnia

Insomnia is dissatisfaction with sleep quantity or quality, with difficulty initiating sleep, difficulty maintaining sleep, or early morning awakening with inability to return to sleep, despite adequate opportunity to sleep, and with daytime impairment. It is among the most common complaints in medical practice, it is a risk factor for depression, anxiety, hypertension, diabetes, falls and accidents, and it is usually perpetuated by learned behaviours even after the trigger has gone.

Definition of insomnia disorder.

Dissatisfaction with sleep with one or more of: difficulty initiating sleep (sleep latency over 30 minutes), difficulty maintaining sleep (wake after sleep onset over 30 minutes), or early awakening (30 minutes or more before desired time). These occur at least 3 nights each week, with distress or daytime impairment (fatigue, poor concentration, mood disturbance, irritability, errors, worry about sleep), despite adequate opportunity to sleep.

Short term insomnia lasts under 3 months. Chronic insomnia lasts 3 months or longer. A sleep efficiency (time asleep divided by time in bed) under 85% supports the complaint.

Classification

• Acute (adjustment) insomnia: triggered by stress, illness, travel, noise or grief, lasting days to weeks.
• Chronic insomnia disorder: primary or comorbid (with depression, anxiety, pain, chronic illness, substance use). The term comorbid insomnia replaces secondary insomnia because the disorder often persists independently and needs its own treatment.
• Insomnia caused by drugs or substances (caffeine, alcohol, nicotine, stimulants, corticosteroids, decongestants, bupropion, SSRIs, beta agonists, theophylline, levodopa, thyroid hormone, antiepileptics, montelukast, and withdrawal from sedatives).
• Circadian rhythm sleep disorders: delayed sleep phase, advanced sleep phase, irregular sleep wake rhythm, shift work disorder and jet lag.
• Sleep related breathing disorders, restless legs syndrome, periodic limb movement disorder, and parasomnias that present as insomnia.
• Paradoxical insomnia (sleep state misperception) and inadequate sleep hygiene.

Epidemiology. About 30% of adults report insomnia symptoms in a year, 10% meet criteria for chronic insomnia disorder, and prevalence is higher in women, older adults, shift workers, and people with psychiatric and medical illness.

Mechanisms (three P model). Predisposing factors (hyperarousal trait, genetics), precipitating factors (stress, illness, loss), and perpetuating factors (extended time in bed, daytime naps, irregular schedule, conditioned arousal in bed, catastrophic beliefs about sleep, alcohol and caffeine use). Hyperarousal involves raised cortisol, heart rate, metabolic rate and cortical beta activity.

Key distinctions. Insomnia with unrefreshing sleep, loud snoring and witnessed pauses suggests sleep apnoea. Evening leg discomfort relieved by movement suggests restless legs syndrome. Early morning waking with low mood suggests depression. Sleep onset only after 02:00 with normal duration if allowed to sleep late suggests delayed sleep phase. Short sleepers who are not impaired do not have insomnia.

History

• Sleep complaint: onset, duration, nights each week, bedtime, time to fall asleep, number and length of awakenings, final wake time, total sleep, daytime naps, and what the patient does when awake in bed (clock watching, using screens, eating).
• Timing and consistency of the sleep schedule on work days and days off; shift work; travel.
• Bedtime routine and environment: light, noise, temperature, bed partner, pets, children, mattress.
• Daytime effects: sleepiness (as distinct from fatigue), concentration, mood, accidents, driving safety, work performance.
• Evening and night behaviour: caffeine (timing and total), alcohol (used as sleep aid), nicotine, heavy meals, exercise, screen use, late night work.
• Sleep apnoea features: snoring, witnessed apnoeas, gasping, nocturia, morning headache, dry mouth, hypertension, neck circumference, obesity.
• Restless legs features: urge to move legs with unpleasant sensation, worse in the evening and at rest, relieved by movement; periodic limb movements reported by a partner; iron deficiency, pregnancy, renal failure, neuropathy.
• Parasomnias: sleepwalking, night terrors, acting out dreams (REM sleep behaviour disorder), nocturnal eating, bruxism, nocturnal seizures.
• Mood and anxiety: depression, anxiety, panic at night, trauma and nightmares, mania, psychosis, and suicidal thoughts.
• Medical conditions: pain, arthritis, heart failure (orthopnoea, paroxysmal nocturnal dyspnoea), asthma and COPD, gastro-oesophageal reflux, nocturia (prostate disease, diabetes), thyroid disease, menopause (night sweats), Parkinson disease, dementia, cancer, chronic kidney disease, itch, and fibromyalgia.
• Drugs: antidepressants (SSRIs, SNRIs, bupropion), corticosteroids, stimulants, decongestants, beta agonists, theophylline, diuretics at night, levodopa, antiepileptics, statins (lipophilic), beta blockers, montelukast, and sedative withdrawal.
• Previous treatments: hypnotics, supplements, over the counter sleep aids (antihistamines), cannabis, and response.
• Two week sleep diary (bedtime, sleep latency, awakenings, final wake, time out of bed, naps, caffeine, alcohol, medicines, and quality rating), and an Insomnia Severity Index.

Examination

• Weight, body mass index, neck circumference (over 40 cm raises sleep apnoea risk), blood pressure, heart rate and rhythm.
• Upper airway: Mallampati class, tonsils, retrognathia, nasal obstruction, and jaw structure.
• Cardiorespiratory signs: heart failure, wheeze, and oedema.
• Thyroid, signs of anaemia, and neurological examination (tremor, rigidity, neuropathy, restless legs).
• Mental state: mood, anxiety, psychosis, cognition and risk.
• Bedside tests: Insomnia Severity Index (0 to 28: 8 to 14 subthreshold, 15 to 21 moderate, 22 to 28 severe), Epworth Sleepiness Scale (over 10 abnormal). STOP-BANG (score of 3 or more raises risk of sleep apnoea), PHQ-9, GAD-7, and the International Restless Legs Syndrome Study Group criteria.

Red flags

• Loud snoring with witnessed apnoeas, obesity, or morning headaches (sleep apnoea).
• Severe daytime sleepiness, sleep attacks, or near miss driving accidents (narcolepsy, apnoea).
• Cataplexy, sleep paralysis, or vivid hallucinations at sleep onset.
• Violent or injurious behaviour during sleep, or acting out dreams (REM sleep behaviour disorder, which can herald synucleinopathy).
• Suicidal ideation, severe depression, mania (reduced need for sleep with elevated mood), or psychosis.
• Delirium or acute confusion at night.
• Alcohol or sedative dependence, or abrupt withdrawal.
• New neurological symptoms, focal signs, or progressive cognitive decline.
• Severe orthopnoea, nocturnal dyspnoea, or chest pain at night.
• Postpartum period with severe sleep loss and mood change.
• Pregnancy with restless legs, pre-eclampsia features, or symptoms suggesting sleep apnoea.
• Sudden onset in an older adult without a trigger.

Special groups

• Children and adolescents: behavioural insomnia of childhood (limit setting, sleep onset association), delayed sleep phase in adolescents, ADHD, autism, and screen use. Behavioural treatment first.
• Pregnancy: restless legs, reflux, nocturia, anxiety and sleep apnoea. Avoid hypnotics where possible.
• Older adults: advanced sleep phase, fragmented sleep, nocturia, pain, polypharmacy, and dementia. Hypnotics carry high risk of falls, fracture and delirium.
• Shift workers: planned naps, light exposure, melatonin timed to sleep, and modafinil for sleepiness if needed.
• Chronic illness: treat pain, dyspnoea, itch and reflux; check drugs.
• Region specific: noise and heat, shared rooms, khat and tea use, night shift labour, and conflict related trauma.

Primary insomnia disorders

• Acute (adjustment) insomnia.
• Chronic insomnia disorder (psychophysiological).
• Paradoxical insomnia (sleep state misperception).
• Inadequate sleep hygiene.
• Behavioural insomnia of childhood.
• Short sleeper (normal variant).

Psychiatric

• Major depressive disorder and persistent depressive disorder.
• Bipolar disorder (mania or hypomania with reduced need for sleep).
• Generalised anxiety disorder, panic disorder and obsessive compulsive disorder.
• Posttraumatic stress disorder and nightmare disorder.
• Psychotic disorders.
• Substance use disorders and withdrawal.
• Adjustment disorder and grief.

Sleep disorders

• Obstructive sleep apnoea, central sleep apnoea, and obesity hypoventilation.
• Restless legs syndrome and periodic limb movement disorder.
• Circadian rhythm disorders (delayed and advanced sleep phase, irregular, non-24 hour, shift work, jet lag).
• Parasomnias: REM sleep behaviour disorder, non-REM arousal disorders, nightmares, sleep related eating disorder.
• Sleep related epilepsy and nocturnal frontal lobe seizures.
• Narcolepsy and idiopathic hypersomnia (insomnia with sleepiness).
• Nocturnal gastro-oesophageal reflux and bruxism.

Medical causes

• Pain: osteoarthritis, rheumatoid arthritis, fibromyalgia, neuropathy, and cancer pain.
• Cardiac: heart failure, angina, and arrhythmia.
• Respiratory: asthma, COPD, chronic cough and cystic fibrosis.
• Endocrine: hyperthyroidism, diabetes (nocturia, hypoglycaemia), menopause, and Cushing syndrome.
• Gastrointestinal: reflux, peptic ulcer, and inflammatory bowel disease.
• Genitourinary: prostate enlargement, nocturia, overactive bladder.
• Neurological: Parkinson disease, dementia, stroke, multiple sclerosis, headache disorders, and traumatic brain injury.
• Dermatological: chronic itch.
• Renal and hepatic disease (uraemic pruritus, restless legs, encephalopathy).
• Pregnancy, malignancy, and HIV.
• Iron deficiency anaemia.

Substances and drugs

• Caffeine, nicotine, alcohol (rebound awakening), cannabis, stimulants, cocaine, and khat.
• Antidepressants (fluoxetine, venlafaxine, bupropion), corticosteroids, decongestants, theophylline, beta agonists, levodopa, thyroid hormone excess, statins, montelukast, antiepileptics (lamotrigine, levetiracetam), diuretics at night, and efavirenz.
• Withdrawal from benzodiazepines, Z drugs, opioids, alcohol and barbiturates.

Step 1. Clinical diagnosis. Insomnia is a clinical diagnosis from history and a 2 week sleep diary. Confirm the duration, frequency, daytime consequences, and the absence of another sleep disorder that fully explains the complaint. Identify perpetuating factors and the patient's beliefs about sleep. Measure severity with the Insomnia Severity Index and repeat to follow treatment. Complete a screen for depression (PHQ-9), anxiety (GAD-7), bipolar disorder, alcohol (AUDIT-C) and suicide risk.

Step 2. Screen for other sleep disorders

• Obstructive sleep apnoea: STOP-BANG score (snoring, tiredness, observed apnoea, pressure, BMI over 35 kg/m2, age over 50 years, neck over 40 cm, male sex). A score of 3 to 4 is intermediate and 5 or more high risk.
• Restless legs syndrome: diagnostic criteria (urge to move, worse at rest, relieved by movement, worse in evening or night, not explained by another condition).
• Circadian disorder: sleep diary showing a fixed late or early sleep window with normal duration when allowed.
• Parasomnia, nocturnal seizures or narcolepsy features: refer for polysomnography.

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

• Full blood count, ferritin and transferrin saturation (restless legs: ferritin under 75 micrograms/L), urea, creatinine, electrolytes, calcium, liver tests, glucose or HbA1c, thyroid stimulating hormone, and vitamin B12.
• Pregnancy test, urine drug screen and blood alcohol if substance use is suspected.
• ECG in patients with palpitations or before using QT prolonging drugs.

Step 4. Targeted tests

• Polysomnography (attended overnight sleep study) for suspected sleep apnoea with comorbid heart failure, respiratory disease or neuromuscular disease, narcolepsy, REM sleep behaviour disorder, parasomnias with injury, nocturnal seizures, treatment resistant insomnia, and suspected periodic limb movements.
• Home sleep apnoea testing for uncomplicated moderate to high probability obstructive sleep apnoea (apnoea-hypopnoea index of 5 or more with symptoms, or 15 or more without).
• Actigraphy (7 to 14 days) for circadian rhythm disorders, irregular schedules and sleep state misperception.
• Multiple sleep latency test for suspected narcolepsy or idiopathic hypersomnia.
• Electroencephalogram with sleep for suspected nocturnal seizures.
• Cognitive testing if memory complaints, neuroimaging for focal signs.
• Serum bicarbonate and arterial blood gas for obesity hypoventilation (bicarbonate 27 mmol/L or more).

Interpretation. Polysomnography is not needed for typical insomnia. Sleep diary data guide sleep restriction. Treat both insomnia and any coexisting sleep apnoea, since untreated apnoea reduces response to cognitive behavioural therapy.

Limits. Subjective sleep time and objective measures often differ in insomnia. Questionnaires screen and do not diagnose. Normal investigations are expected in primary insomnia.

Immediate. Reassure, set expectations and screen for risk. Treat urgent conditions (suicidal ideation, mania, psychosis, delirium, withdrawal, heart failure, severe pain). Provide brief sleep education and arrange follow up in 2 to 4 weeks. Warn about drowsy driving.

Cognitive behavioural therapy for insomnia (first line for chronic insomnia in all adults, including older adults)

• Structured programme over 4 to 8 weekly sessions (face to face, group, telephone, or digital), with benefits equal to drug treatment in the short term and better over the long term. About 70 to 80% improve, and about 40% achieve remission.
• Components:
  • Sleep restriction: set time in bed to the average total sleep time from the diary (minimum 5 hours, 5.5 hours in some settings), with a fixed wake time. Extend by 15 to 30 minutes each week when sleep efficiency exceeds 90%, and reduce if under 85%.
  • Warn about transient sleepiness early in treatment, and avoid in bipolar disorder, epilepsy, parasomnias and untreated sleep apnoea unless supervised.
  • Stimulus control: go to bed only when sleepy, leave bed after about 15 to 20 minutes awake, use the bed only for sleep and sex, and keep a fixed wake time.
  • Cognitive therapy for unhelpful beliefs about sleep and daytime consequences.
  • Relaxation, paradoxical intention and mindfulness.
  • Sleep hygiene as support only (caffeine under 200 mg daily and not after midday, no alcohol near bedtime, stop nicotine). Other measures: regular exercise but not within 2 to 3 hours of bedtime, dark cool quiet bedroom, limit screens for 1 hour before bed, avoid naps or limit to 20 minutes before 15:00.
  • Sleep hygiene alone is not effective for chronic insomnia.

Drug treatment (adjunct to cognitive behavioural therapy, for short term use of under 4 weeks, at the lowest effective dose, intermittently)

Use only after assessment of the cause, a discussion of risks, and with a plan to stop. Avoid in sleep apnoea, respiratory depression, substance misuse, pregnancy and driving, and in older adults when possible.

• Zolpidem 5 mg orally at bedtime in women (increased to 10 mg only if needed) and 5 to 10 mg in men (maximum 10 mg; 5 mg in older adults and in hepatic impairment), only when 7 to 8 hours remain before waking. Not for use for more than 4 weeks.
• Zopiclone 3.75 mg orally at bedtime, increased to 7.5 mg if needed (maximum 7.5 mg; 3.75 mg in older adults and in hepatic or severe kidney impairment). Bitter taste. Not for use for more than 4 weeks.
• Eszopiclone 1 mg orally at bedtime, increased to 2 or 3 mg (maximum 2 mg in older adults and in severe hepatic impairment).
• Temazepam 10 to 20 mg orally at bedtime (maximum 40 mg; 10 mg in older adults), for 2 to 4 weeks at most.
• Lorazepam 0.5 to 1 mg orally at bedtime for the shortest period (maximum 2 mg), and avoid in older adults.
• Melatonin prolonged release 2 mg orally 1 to 2 hours before bedtime, for adults aged 55 years or more, for up to 13 weeks (evidence for a modest effect). Immediate release 0.5 to 5 mg 30 to 60 minutes before the target bedtime is used for delayed sleep phase and jet lag.
• Daridorexant 25 mg orally within 30 minutes before bedtime (maximum 50 mg; 25 mg in moderate hepatic impairment), suvorexant 10 mg (maximum 20 mg; not with strong CYP3A inhibitors), or lemborexant 5 mg (maximum 10 mg). Orexin receptor antagonists have lower dependence potential. Avoid in narcolepsy and severe hepatic impairment.
• Doxepin 3 mg orally at bedtime, up to 6 mg (maximum 6 mg), for sleep maintenance insomnia. Avoid with monoamine oxidase inhibitors.
• Trazodone 25 to 50 mg orally at night, up to 100 mg (off label), and mirtazapine 7.5 to 15 mg at night when depression coexists. Amitriptyline 10 to 25 mg at night is an option with strong caution (anticholinergic effects, cardiac effects, overdose danger).
• Antihistamines (diphenhydramine 25 to 50 mg, promethazine 10 to 25 mg) are for short term use only (maximum 7 days), and are avoided in older adults, glaucoma, urinary retention and dementia.
• Quetiapine, olanzapine and gabapentinoids are not first line for insomnia because of metabolic and other risks, and are used only for a co-existing indication.
• Risks of hypnotics: next day impairment (driving, falls, hip fracture, confusion), complex sleep behaviours (sleepwalking, sleep driving, eating, with a risk of injury, particularly with zolpidem, zopiclone and eszopiclone: stop at once if they occur).
• Tolerance, dependence and rebound insomnia.
• Respiratory depression with opioids and alcohol.
• Cognitive effects in older adults.
• Stopping hypnotics after more than 4 weeks: reduce the dose by 10 to 25% every 1 to 2 weeks, with cognitive behavioural therapy support. When a switch to a long acting drug is needed, diazepam 10 mg is roughly equivalent to temazepam 20 mg or zopiclone 7.5 mg.

Treatment of the cause or comorbid condition

• Depression and anxiety: treat with psychological therapy and an SSRI or mirtazapine. Insomnia treatment improves depression outcomes.
• Obstructive sleep apnoea: continuous positive airway pressure (auto titrating 4 to 20 cmH2O, adherence of 4 hours or more on most nights), weight loss, positional therapy, mandibular advancement devices, and treat nasal obstruction.
• Restless legs syndrome: if ferritin is under 75 micrograms/L or transferrin saturation under 20%, give ferrous sulphate 200 mg (65 mg elemental iron) orally once daily or on alternate days with vitamin C for 3 months. Give intravenous ferric carboxymaltose 500 to 1000 mg once if intolerant or malabsorption exists.
• First line drug: gabapentin 300 mg orally at night increased to 900 to 1800 mg daily in divided doses (reduce in kidney impairment), or pregabalin 75 mg at night increased to 150 to 300 mg.
• Dopamine agonists (pramipexole 0.125 mg 2 to 3 hours before bed increased to a maximum of 0.5 mg, or ropinirole 0.25 mg increased to a maximum of 4 mg) are second line because of augmentation, impulse control disorders and rebound.
• Stop antihistamines and review antidepressants.
• Circadian rhythm disorders: fixed wake time, bright light on waking (10000 lux for 30 minutes) for delayed phase, melatonin 0.5 mg 5 hours before the habitual sleep onset or 3 mg 2 to 3 hours before target bedtime, and avoid evening light.
• Shift work: planned naps, bright light in the shift, dark glasses on the way home, and melatonin 3 mg before daytime sleep.
• Nocturia: restrict evening fluids, treat prostate disease, diabetes and heart failure, desmopressin melt 25 micrograms sublingually at bedtime in women and 50 micrograms in men (check sodium at 3 days; avoid in over 65 years with heart failure or hyponatraemia).
• Pain: scheduled analgesia, topical therapy, and review of opioids.
• Reflux, asthma and COPD: optimise treatment, and raise the head of the bed.
• Menopause: hormone therapy if there are vasomotor symptoms and no contraindication (transdermal estradiol 50 micrograms), or fezolinetant 45 mg daily.
• Drugs: move stimulating drugs to the morning, review doses, and avoid caffeine, nicotine and alcohol.
• REM sleep behaviour disorder: safe bedroom, clonazepam 0.25 to 2 mg at night (avoid in apnoea and dementia) or melatonin 3 to 12 mg at night, and neurological assessment.
• Nightmares with posttraumatic stress disorder: prazosin 1 mg at night increased every 3 days to 3 to 15 mg, and trauma focused therapy.

Special populations

• Pregnancy and breastfeeding: sleep hygiene, cognitive behavioural therapy, iron for restless legs, and avoid hypnotics. Short term diphenhydramine 25 mg is considered when needed.
• Children and adolescents: behavioural treatment first, regular schedule and limits. Melatonin 1 to 5 mg 30 to 60 minutes before bedtime for children with ADHD or autism (under specialist direction), and evening light restriction for delayed sleep phase.
• Older adults: cognitive behavioural therapy for insomnia, melatonin prolonged release 2 mg, low dose doxepin 3 mg, or daridorexant 25 mg if a drug is needed. Avoid benzodiazepines, Z drugs, antihistamines and tricyclic antidepressants.
• Kidney and liver impairment: lowest doses, avoid benzodiazepines in hepatic encephalopathy, and reduce gabapentin and pregabalin in kidney impairment.

Monitoring. Sleep diary and Insomnia Severity Index at 2 to 4 weeks, then monthly until stable. Review sleep efficiency, daytime function, mood, drug use, alcohol and caffeine, adverse effects (next day sedation, complex sleep behaviours, falls), and duration of any hypnotic.

Referral and escalation. Sleep medicine for suspected sleep apnoea, narcolepsy, REM sleep behaviour disorder, parasomnias with injury, circadian disorders, periodic limb movements, and treatment failure. Psychiatry or psychology for severe depression, bipolar disorder, trauma and cognitive behavioural therapy for insomnia. Neurology for nocturnal seizures and movement disorders. ENT or dental sleep medicine for upper airway problems. Addiction services for hypnotic or alcohol dependence.

Admission criteria. Rarely needed. Consider for acute suicidal risk, mania, psychosis, delirium, severe withdrawal, or sleep apnoea with hypercapnic respiratory failure.

Discharge and follow up. Provide a written sleep plan and diary. Review within 2 to 4 weeks, then at 3 months. Safety net advice: return for suicidal thoughts, no sleep for several nights with elevated mood, driving drowsiness, falls, sleepwalking or other complex behaviours on hypnotics, witnessed apnoeas, or worsening daytime function.