Key Facts

Insomnia is the most common sleep disorder and one of the most frequent complaints in primary care. It is both a symptom and an independent disorder with significant health consequences. Management should prioritise non-pharmacological approaches.

Epidemiology

• Intermittent insomnia symptoms: 30-35% of adults
• Chronic insomnia disorder: 6-10%
• Female:male ratio 1.5:1
• Prevalence increases with age
• Strong bidirectional association with depression and anxiety

Aetiology

• Primary insomnia: no identifiable medical or psychiatric cause (diagnosis of exclusion)
• Comorbid insomnia: depression, anxiety, chronic pain, COPD, heart failure, GORD, menopause, nocturia
• Substance-related: caffeine, alcohol, nicotine, stimulants, medication effects (SSRIs, steroids, beta-blockers)
• Other sleep disorders: OSA, restless legs syndrome, circadian rhythm disorders
• 3P model (Spielman): Predisposing (personality, genetics) + Precipitating (life events, illness) + Perpetuating (maladaptive sleep behaviours, worry about sleep)

Pathophysiology

• Hyperarousal model: physiological (increased cortisol, metabolic rate, heart rate), cognitive (rumination, worry), and cortical (increased beta EEG activity during sleep)
• Disrupted circadian rhythm regulation (melatonin, cortisol)
• Conditioned arousal: bed/bedroom becomes associated with wakefulness rather than sleep
• Compensatory behaviours (sleeping late, napping, excessive time in bed) perpetuate insomnia

Symptoms

• Difficulty falling asleep (sleep-onset insomnia)
• Difficulty staying asleep (sleep-maintenance insomnia)
• Early morning awakening with inability to return to sleep
• Non-restorative sleep
• Daytime consequences: fatigue, poor concentration, mood disturbance, reduced performance, irritability
• Preoccupation or worry about sleep

Assessment

• Sleep history: sleep-wake pattern, bedtime, wake time, time to fall asleep, number of awakenings, total sleep time
• Sleep diary: 2 weeks minimum
• Daytime functioning
• Bedroom environment
• Caffeine, alcohol, drug use
• Screen for depression (PHQ-9), anxiety (GAD-7), OSA (STOP-BANG)

Red Flags

• Excessive daytime sleepiness with snoring (OSA)
• Restless legs/periodic limb movements
• Narcolepsy symptoms (cataplexy, sleep paralysis)
• Parasomnias (sleepwalking, REM sleep behaviour disorder)
• Insomnia with cognitive decline in elderly (delirium, dementia)

Bedside

• Sleep diary: 2 weeks; record bedtime, wake time, sleep latency, awakenings, daytime naps
• Validated questionnaires: Insomnia Severity Index (ISI), Pittsburgh Sleep Quality Index (PSQI)
• PHQ-9, GAD-7: screen for comorbid depression and anxiety
• STOP-BANG: screen for OSA
• Epworth Sleepiness Scale: if excessive daytime sleepiness

Bloods

• TFTs (hyper/hypothyroidism)
• FBC (anaemia, restless legs — ferritin if RLS suspected)
• Ferritin (if restless legs suspected; treat if <75mcg/L)
• HbA1c (diabetes — nocturia)

Special Tests

• Polysomnography: NOT routinely indicated for insomnia; reserved for suspected OSA, PLMD, narcolepsy, or diagnostic uncertainty
• Actigraphy: wrist-worn device measuring sleep-wake patterns over 1-2 weeks; useful for circadian rhythm disorders

Non-pharmacological — First-Line

• CBT-I (Cognitive Behavioural Therapy for Insomnia): first-line treatment (NICE, AASM)
  • Components: sleep restriction, stimulus control, cognitive restructuring, relaxation, sleep hygiene
  • Sleep restriction: limit time in bed to match actual sleep time (initially may be 5-6 hours); gradually increase
  • Stimulus control: bed only for sleep and sex; leave bed if awake >15-20 minutes; fixed wake time
  • Delivery: face-to-face, group, digital (Sleepio app — NHS approved)
  • Efficacy: 70-80% improvement; durable effects lasting months-years
• Sleep hygiene (component of CBT-I, limited evidence alone):
  • Regular sleep-wake schedule
  • Avoid caffeine after midday, alcohol before bed
  • Cool, dark, quiet bedroom
  • Avoid screens 1 hour before bed
  • Regular exercise (but not within 4 hours of bed)

Pharmacological — Second-Line/Short-Term Only

• Melatonin MR 2mg (Circadin): licensed for patients ≥55 years; up to 13 weeks; relatively safe
• Z-drugs (zopiclone 3.75-7.5mg, zolpidem 5-10mg): maximum 2-4 weeks; risk of dependence, rebound insomnia, falls, daytime sedation
• Short-acting benzodiazepines (temazepam 10-20mg): maximum 2-4 weeks; AVOID in elderly
• Low-dose amitriptyline (10-25mg ON): off-label; useful if comorbid chronic pain or depression
• Antihistamines (promethazine 25mg, diphenhydramine): short-term; anticholinergic side effects; AVOID in elderly
• Orexin receptor antagonists (suvorexant, lemborexant): newer agents; not widely used in UK

Referral Criteria

• Sleep clinic: suspected OSA, narcolepsy, parasomnia, complex circadian rhythm disorder
• Psychology/IAPT: for CBT-I (available through NHS talking therapies)
• Psychiatry: insomnia with severe mental health comorbidity
• Avoid ongoing hypnotic prescriptions without review

• CBT-I: sustained benefit in >70% at 12 months; superior to medications long-term
• Hypnotics: effective short-term; high relapse on discontinuation; dependence risk
• Chronic insomnia is often a long-term condition requiring ongoing self-management
• Untreated insomnia: associated with 2× risk of depression, 1.5× risk of hypertension, cardiovascular disease, and impaired immune function
• Insomnia in elderly: associated with increased falls, cognitive decline, and mortality
• Most patients can achieve significant improvement with appropriate management

CBT-I Components Summary

Insomnia Severity Index (ISI)

Hypnotic Prescribing Safety (NICE CKS)