Insomnia — Symptoms, Causes & Treatment | MyMedicPlus

Insomnia disorder is defined as dissatisfaction with sleep quantity or quality, despite adequate opportunity for sleep, causing significant daytime distress or functional impairment, occurring at least 3 nights per week for at least 3 months (chronic insomnia). It encompasses difficulty initiating sleep (sleep-onset insomnia), maintaining sleep (sleep maintenance insomnia), and early morning awakening. Insomnia affects 10–30% of adults globally, is twice as common in women, and is strongly associated with anxiety, depression, and chronic pain. Cognitive behavioral therapy for insomnia (CBT-I) is the evidence-based first-line treatment, outperforming medication in long-term outcomes. Insomnia is categorised as acute (transient — less than 3 months, typically stress-related) or chronic (more than 3 months, perpetuated by maladaptive behaviours and cognitions). The hyperarousal model of insomnia — elevated physiological arousal (increased cortisol, elevated core body temperature, increased CNS activity) combined with negative automatic thoughts about sleep — explains why CBT-I targeting both physiological and cognitive components is the most effective treatment. The global economic cost of insomnia through lost productivity and healthcare utilisation is estimated at over $400 billion per year in the USA alone.

The '3P model' explains chronic insomnia: predisposing factors (anxiety-prone personality, female sex, older age, family history), precipitating factors (acute stress, illness, bereavement, major life changes), and perpetuating factors (maladaptive behaviors and cognitions that maintain insomnia after the precipitant resolves — spending excessive time in bed, catastrophizing about sleep). Common associated conditions: anxiety and depression (bidirectional relationship), chronic pain, obstructive sleep apnea, restless legs syndrome, menopause, urinary frequency, and GERD. Perpetuating medications: caffeine, stimulants, decongestants, corticosteroids, beta-blockers, and SSRIs. Restless legs syndrome (Willis-Ekbom disease) — an urge to move the legs with uncomfortable sensations, typically worse in the evening and at rest — causes severe sleep-onset difficulty and is a frequently missed cause of insomnia; treated with dopamine agonists (pramipexole, ropinirole) or alpha-2 delta ligands (pregabalin, gabapentin). Obstructive sleep apnoea causes non-restorative sleep, nocturnal arousals, and daytime fatigue that can mimic insomnia — diagnosis by polysomnography; treatment with CPAP prevents arousals and improves sleep quality dramatically. Circadian rhythm disorders including delayed sleep-wake phase disorder (inability to fall asleep until the early morning hours) are misdiagnosed as insomnia — treated with chronotherapy or timed light therapy.

Sleep-related symptoms: prolonged sleep latency (more than 30 minutes to fall asleep), frequent nocturnal awakenings lasting more than 30 minutes, early morning awakening (more than 30 minutes before desired wake time), non-restorative or poor quality sleep. Daytime consequences: fatigue, difficulty concentrating, memory impairment, mood disturbance (irritability, anxiety, low mood), reduced motivation, and occupational or social impairment. Patients with insomnia have heightened physiological and cognitive arousal (elevated cortisol, increased core body temperature, and negative automatic thoughts about sleep) — in contrast to other sleep disorders where patients feel genuinely sleepy but cannot stay awake. The Insomnia Severity Index (ISI) — a validated 7-item self-report questionnaire — grades severity: scores 0–7 (no clinically significant insomnia), 8–14 (subthreshold insomnia), 15–21 (moderate insomnia), 22–28 (severe insomnia). The Epworth Sleepiness Scale (ESS) — assessing propensity to fall asleep in mundane situations — is typically normal in primary insomnia (distinguishing it from excessive daytime sleepiness from sleep apnoea or narcolepsy, where ESS above 10 indicates pathological sleepiness). Actigraphy — wrist-worn motion sensor worn for 1–2 weeks — objectively documents sleep-wake patterns including sleep latency, total sleep time, and sleep efficiency.

Insomnia is primarily a clinical diagnosis based on thorough sleep history (onset, duration, pattern, precipitants, sleep hygiene), a 2-week sleep diary (bedtime, wake time, time to fall asleep, number of awakenings, total sleep time), and assessment of daytime impairment using validated tools (Insomnia Severity Index, Epworth Sleepiness Scale — typically normal in insomnia). Exclude underlying conditions: depression and anxiety screening, restless legs syndrome assessment, and obstructive sleep apnea (if snoring, obesity, or witnessed apneas). Polysomnography (overnight sleep study) is not routinely required for insomnia but is indicated when other sleep disorders are suspected. The Pittsburgh Sleep Quality Index (PSQI) — a 19-item retrospective questionnaire — assesses sleep quality over the past month across seven domains, with a score above 5 indicating poor sleep quality. Polysomnography is reserved for suspected periodic limb movement disorder (PLMD), suspected parasomnias (REM sleep behaviour disorder, sleepwalking), or when treatment-refractory insomnia does not respond to CBT-I after 6–8 weeks.

Cognitive Behavioral Therapy for Insomnia (CBT-I) is the NICE, AASM, and ESS recommended first-line treatment — consistently superior to medications in long-term outcomes and produces sustained benefit without dependence. CBT-I components: sleep restriction therapy (limits time in bed to build sleep pressure), stimulus control (bed only for sleep and sex), cognitive restructuring (challenging sleep-related catastrophic thoughts), relaxation techniques, and sleep hygiene education. Pharmacological treatment for short-term use: melatonin receptor agonists (ramelteon), orexin receptor antagonists (suvorexant, lemborexant) — favorable safety profile; Z-drugs (zopiclone, zolpidem) — short-term only (maximum 2–4 weeks) due to dependence risk; low-dose doxepin for sleep maintenance. The AASM (American Academy of Sleep Medicine) 2017 clinical guideline recommends CBT-I as first-line treatment for chronic insomnia disorder in adults, rated as strong recommendation. Digital CBT-I (Sleepio, Somryst — FDA-cleared digital therapeutic) provides structured online CBT-I programs with equivalent efficacy to therapist-delivered CBT-I in randomised trials — massively increasing access to the gold standard treatment. Doxylamine (antihistamine sedative — first-generation) has significant anticholinergic effects and is not recommended for chronic insomnia due to tolerance development and cognitive side effects in the elderly.

Chronic insomnia substantially impairs quality of life, work performance, and safety — insomnia is associated with doubled risk of road traffic accidents. Long-term insomnia significantly increases risk of depression (3-fold), anxiety disorders, hypertension, diabetes, cardiovascular disease, and immune dysfunction. Dependence on benzodiazepines and Z-drugs is a serious iatrogenic complication — long-term use impairs sleep architecture, reduces restorative slow-wave sleep, and causes psychological dependence and significant withdrawal symptoms including rebound insomnia. Excessive daytime fatigue from chronic insomnia impairs cognitive performance, affecting academic, occupational, and social functioning.

Sleep hygiene forms the foundation: maintain consistent sleep and wake times (even on weekends), limit bed to sleep and sex, avoid screens (blue light suppresses melatonin) for 1 hour before bed, keep the bedroom cool, dark, and quiet, avoid caffeine after 2 pm and alcohol within 3 hours of sleep (alcohol fragments sleep architecture despite aiding sleep onset). Address anxiety and stress with psychological support or therapy. Develop a consistent wind-down routine 30–60 minutes before bedtime. Avoid lying awake in bed — if not asleep within 20 minutes, get up and do something calming in dim light until sleepy. CBT-I is more effective and longer-lasting than any sleep medication and should be the first-line treatment for chronic insomnia.

See a GP for: insomnia persisting beyond 4 weeks that is significantly impairing daytime function (fatigue, concentration, mood, work performance); insomnia associated with significant anxiety, depression, or trauma — these underlying conditions should be treated alongside sleep; suspicion of a comorbid sleep disorder (sleep apnoea — loud snoring with observed breathing pauses, waking unrefreshed; restless leg syndrome — uncomfortable urge to move legs disrupting sleep onset); or when over-the-counter sleep aids are being used regularly for more than 2-3 weeks. Seek urgent help for: insomnia combined with suicidal thoughts (insomnia is an independent risk factor for suicide and should be taken seriously in this context); or insomnia combined with new severe physical symptoms (chest pain, breathlessness, palpitations — these may have a treatable organic cause). Avoid requesting sleeping tablets as a first-line solution — CBT-I (cognitive behavioural therapy for insomnia) is the most effective long-term treatment and should be tried before hypnotic medication. Self-referral to IAPT (Improving Access to Psychological Therapies) in the UK provides access to digital and face-to-face CBT-I.