Insomnia
Exam Tips
- In OSCEs, insomnia diagnosis requires daytime impairment plus adequate sleep opportunity; poor sleep alone is insufficient.
- Classify by duration/frequency: chronic insomnia = symptoms at least 3 nights/week for at least 3 months.
- Always screen for red flags of alternative sleep disorders (snoring/witnessed apnoea, urge to move legs, sudden daytime sleep attacks).
- State CBT-I as first-line and explain why: stronger long-term outcomes than hypnotics.
- If prescribing hypnotics, mention explicit safety counselling: short course only, dependence risk, no alcohol, and driving/next-day sedation advice.
- Use a 2-week sleep diary and an objective baseline score (for example ISI) to demonstrate structured assessment and follow-up.
Definition
Insomnia disorder is a persistent problem with sleep initiation, sleep maintenance, early morning waking, or non-restorative sleep despite adequate opportunity and environment for sleep. For diagnosis, the night-time sleep complaint must cause clinically meaningful daytime impairment (for example fatigue, mood disturbance, poor concentration, reduced functioning), and not just dissatisfaction with sleep quantity. In adults, short-term insomnia is typically <3 months, whereas chronic insomnia occurs at least 3 nights per week for 3 months or more.
Pathophysiology
Insomnia is best explained by a biopsychosocial hyperarousal model: predisposition (genetic/trait anxiety), precipitating stressors (for example bereavement, illness, exams), and perpetuating factors (maladaptive sleep behaviours and dysfunctional beliefs) interact to maintain symptoms. Neurobiologically, increased cognitive and physiological arousal (heightened sympathetic activity, conditioned wakefulness in bed) disrupts normal sleep-wake regulation. From a sleep physiology perspective, insomnia reflects dysregulation between circadian timing (Process C) and homeostatic sleep drive (Process S), often worsened by irregular schedules, daytime napping, caffeine/alcohol, and comorbid psychiatric or medical illness.
Risk Factors
- Female sex and perimenopause/menopause
- Older age
- Stressful life events (bereavement, financial stress, deadlines, illness)
- Shift work, jet lag, environmental sleep disruption (noise, light, temperature)
- Comorbid mental health disorders (anxiety, depression, PTSD, bipolar disorder, ADHD, autism spectrum disorder)
- Substance use (alcohol, nicotine, high caffeine intake, illicit drugs)
- Comorbid medical illness (chronic pain, COPD, heart failure, diabetes, neurological disease, reflux, tinnitus)
- Coexisting sleep disorders (obstructive sleep apnoea, restless legs syndrome, periodic limb movement disorder)
- Medication adverse effects (for example corticosteroids, SSRIs/SNRIs, beta-blockers)
Clinical Features
Symptoms
- Difficulty falling asleep (prolonged sleep-onset latency)
- Frequent nocturnal awakenings or difficulty returning to sleep
- Early morning awakening
- Non-restorative or poor-quality sleep
- Daytime fatigue, low energy, malaise
- Irritability, reduced mood, anxiety symptoms
- Poor concentration, memory and attention
- Functional impairment (work/study performance, driving safety, relationships)
Signs
- Often no specific abnormal physical signs on examination
- Possible signs of comorbid anxiety/depression on mental state assessment
- Features suggesting alternative sleep pathology (for example obesity/large neck circumference and hypertension suggesting OSA)
- Signs of contributory medical disease (for example tremor/goitre in hyperthyroidism, cardiorespiratory signs, chronic pain behaviours)
Investigations
Management
Lifestyle Modifications
- First-line: offer CBT for insomnia (CBT-I), digital or face-to-face, including stimulus control, sleep restriction, cognitive restructuring, and relapse prevention
- Sleep hygiene as adjunct (regular wake time, wind-down routine, avoid evening caffeine/nicotine/alcohol, limit naps, optimize bedroom light/noise/temperature)
- Address perpetuating behaviours (time in bed while awake, clock-watching, compensatory daytime sleeping)
- Treat comorbid conditions driving insomnia (pain, reflux, menopause symptoms, anxiety/depression, substance misuse)
- Advise on driving and occupational risk where daytime sleepiness is significant
Pharmacological Treatment
Non-benzodiazepine hypnotic (Z-drug)
- Zopiclone 3.75-7.5 mg at bedtime for short-term use only (usually up to 2-4 weeks)
- Zolpidem 5-10 mg at bedtime for short-term use only (usually up to 2-4 weeks)
Use only if insomnia is severe/disabling and daytime function is markedly affected after non-drug measures. Prescribe the lowest effective dose for the shortest duration; review early. Warn about dependence, tolerance, rebound insomnia, next-day psychomotor impairment, falls, confusion, and complex sleep behaviours; avoid alcohol and caution driving the next day.
Benzodiazepine hypnotic
- Temazepam 10-20 mg at bedtime for short-term use only (usually up to 2-4 weeks)
Reserve for exceptional short-term crisis use. Higher risk of dependence, withdrawal, cognitive impairment, falls, and respiratory depression. Avoid or use extreme caution in older adults, myasthenia gravis, severe respiratory insufficiency, sleep apnoea, and history of substance misuse.
Melatonin receptor agonist approach
- Melatonin prolonged-release 2 mg at bedtime (licensed in UK for primary insomnia in adults aged 55 years or over, typically short-term up to 13 weeks)
Consider mainly in older adults with sleep-maintenance issues or when standard hypnotics are unsuitable. Check interactions (for example fluvoxamine can markedly increase melatonin levels); may cause dizziness/somnolence.
Complications
- Reduced quality of life and occupational/academic performance
- Road traffic and workplace accidents due to impaired alertness
- Falls and injury risk, especially in older adults
- Increased risk of depression, anxiety, substance misuse, and possible suicidal behaviour
- Associations with cardiometabolic disease (hypertension, obesity, type 2 diabetes, cardiovascular disease), particularly with short sleep duration
- Potential increase in all-cause mortality in persistent severe insomnia
Prognosis
Acute insomnia often resolves when triggers settle, but around 1 in 5 short-term cases progress to chronic insomnia. Chronic insomnia is frequently persistent over years, especially in older adults, women, and people with severe baseline symptoms or comorbidity. CBT-I has the best evidence for durable improvement, while benefits from hypnotics are usually short-lived and relapse is common after discontinuation.
Sources & References
🏥BMJ Best Practice(1)
💊BNF Drug References(6)
- Chloral hydrate[management.pharmacological]
- Daridorexant[management.pharmacological]
- Diazepam[management.pharmacological]
- Eszopiclone[management.pharmacological]
- Melatonin[management.pharmacological]
- Oxazepam[management.pharmacological]
✅NICE Guidelines(1)
- Insomnia[overview]