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# Insomnia disorder

Trouble falling or staying asleep, or waking too early, at least three nights a week, which affects daytime life. Behavioural therapy works best.

Updated 2026-11-01

## Structures involved

Tap one to see what it is and open it in 3D.

- [Hypothalamus](https://durgical.com/en/anatomy/hypothalamus/)
- [Thalamus](https://durgical.com/en/anatomy/thalamus/)
- [Pineal gland](https://durgical.com/en/anatomy/pineal-gland/)
- [Pons](https://durgical.com/en/anatomy/pons/)
- [Midbrain](https://durgical.com/en/anatomy/midbrain/)
- [Frontal lobe](https://durgical.com/en/anatomy/superior-frontal-gyrus/)

## Why it happens

- [Wakefulness, sleep, the EEG and seizures](https://durgical.com/en/physiology/wakefulness-sleep-the-eeg-and-seizures/)

## What it is

Persistent difficulty starting or keeping sleep, or waking too early, despite adequate opportunity to sleep, that causes distress or daytime impairment. It is chronic when it happens at least 3 nights a week for 3 months, and it often coexists with other mental or medical illness.

## Who gets it

Insomnia symptoms affect about a third of adults and the disorder about one in ten. It is more frequent in women, older adults, shift workers and people with depression, anxiety or chronic pain, and is a common complaint in Colombian primary care and in hospitalised patients.

## Causes

- Stress, life events and hyperarousal
- Psychiatric conditions: depression, anxiety, PTSD, bipolar disorder
- Medical conditions: pain, heart failure, hyperthyroidism, reflux, nocturia, menopause
- Substances and drugs: caffeine, alcohol, nicotine, stimulants, corticosteroids, some antidepressants
- Poor sleep habits, irregular schedules and shift work

## Risk factors

- Female sex and older age
- Anxious temperament and family history
- Psychiatric or chronic medical illness
- Shift or night work and frequent travel across time zones
- Low socioeconomic status and stressful environments

## Pathophysiology

The core is hyperarousal: increased cognitive, emotional and physiological activation (higher metabolic rate, cortisol and fast EEG activity) that opposes the sleep drive. In the 3P model, predisposing traits combine with a precipitating event, and perpetuating behaviours such as long time in bed, napping and worry about sleep turn short-term insomnia into a chronic disorder. The hypothalamic and thalamic systems that switch between wakefulness and sleep stay biased towards waking.

## Classification

- Short-term insomnia: less than 3 months, often linked to a stressor
- Chronic insomnia disorder: at least 3 nights a week for at least 3 months
- By pattern: sleep-onset, sleep-maintenance or early-morning awakening

## Symptoms and signs

- Taking a long time to fall asleep
- Frequent or long awakenings during the night
- Waking too early and being unable to fall back asleep
- Daytime tiredness, poor concentration and memory
- Irritability, low mood and worry about sleep
- Errors and accidents at work or while driving

## Red flags

- Loud snoring, witnessed apnoeas or severe daytime sleepiness (possible sleep apnoea)
- Insomnia with suicidal thoughts or severe depression
- Reduced need for sleep without tiredness (possible mania)
- Drowsy driving or work accidents
- Complex sleep behaviours, such as sleepwalking, after hypnotic use

## Diagnosis

**Clinical**
Clinical diagnosis based on a sleep history, a sleep diary of 1 to 2 weeks and questionnaires such as the Insomnia Severity Index. The assessment looks for psychiatric and medical causes, substance use and other sleep disorders.

**Tests**
Polysomnography is not routine; it is used when sleep apnoea, periodic limb movements or a parasomnia are suspected, or when treatment fails. Actigraphy can document sleep patterns. Thyroid function or other tests as guided by history.

**Imaging**
Not needed.

## Differential diagnosis

- Obstructive sleep apnoea
- Restless legs syndrome
- Circadian rhythm disorders (delayed sleep phase, shift work)
- Depression, anxiety or mania
- Inadequate sleep opportunity (by choice or circumstance)

## Goal of treatment

Improve the quality and quantity of sleep and daytime functioning, treat associated conditions, and avoid long-term dependence on hypnotics.

## Treatment

**Conservative**
Cognitive behavioural therapy for insomnia (CBT-I) is first-line for chronic insomnia: stimulus control, sleep restriction, cognitive work on beliefs about sleep and relaxation.

**Lifestyle**
Sleep hygiene as a complement: regular schedule, limiting caffeine, alcohol and screens at night, and a dark, quiet bedroom.

**Medical**
Short-term medicines when CBT-I is not enough or not available: non-benzodiazepine hypnotics (zolpidem, eszopiclone), orexin receptor antagonists, low-dose doxepin or melatonin receptor agonists.

**Medical**
Treatment of coexisting depression, anxiety, pain or other conditions, which often improves sleep.

**Follow-up**
Nursing care and safety: avoiding benzodiazepines and sedating antihistamines in older adults (falls, confusion), reducing night-time disturbances in hospital and checking for daytime sleepiness.

## Drugs for this condition

- [Zolpidem](https://durgical.com/en/pharmacology/zolpidem/)
- [Eszopiclone](https://durgical.com/en/pharmacology/eszopiclone/)
- [Zopiclone](https://durgical.com/en/pharmacology/zopiclone/)
- [Melatonin](https://durgical.com/en/pharmacology/melatonin/)
- [Ramelteon](https://durgical.com/en/pharmacology/ramelteon/)
- [Suvorexant](https://durgical.com/en/pharmacology/suvorexant/)
- [Temazepam](https://durgical.com/en/pharmacology/temazepam/)
- [Triazolam](https://durgical.com/en/pharmacology/triazolam/)

## Complications

- Depression and anxiety, and higher risk of suicide
- Traffic and work accidents
- Falls and confusion from hypnotics in older adults
- Dependence and rebound insomnia with hypnotics
- Higher cardiovascular and metabolic risk

## Prognosis

Short-term insomnia usually resolves once the trigger passes. Chronic insomnia tends to persist or recur, but CBT-I gives lasting improvement in most patients, with effects that outlast those of medicines.

## Prevention

- Regular sleep and wake times
- Limiting caffeine, alcohol and nicotine in the evening
- Early treatment of short-term insomnia to avoid perpetuating habits

## Test yourself

Think of the answer, then tap the question to see it.

## What is the first-line treatment for chronic insomnia disorder?

Cognitive behavioural therapy for insomnia (CBT-I).

## What frequency and duration define chronic insomnia disorder?

Symptoms at least 3 nights a week for at least 3 months, with daytime impairment.

## When is polysomnography indicated in insomnia?

When another sleep disorder such as sleep apnoea or periodic limb movements is suspected, or treatment fails.

## Which hypnotic drug classes are avoided in older adults because of falls and confusion?

Benzodiazepines and sedating antihistamines.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/conditions/insomnia-disorder/)

## Related conditions

- [Obstructive sleep apnoea](https://durgical.com/en/conditions/obstructive-sleep-apnoea/)
- [Restless legs syndrome](https://durgical.com/en/conditions/restless-legs-syndrome/)
- [Major depressive disorder](https://durgical.com/en/conditions/major-depressive-disorder/)
- [Generalized anxiety disorder](https://durgical.com/en/conditions/generalized-anxiety-disorder/)
- [Alcohol use disorder](https://durgical.com/en/conditions/alcohol-use-disorder/)
- [Delirium](https://durgical.com/en/conditions/delirium/)
- [Graves disease (hyperthyroidism)](https://durgical.com/en/conditions/graves-disease/)
- [Gastro-oesophageal reflux disease (GERD)](https://durgical.com/en/conditions/gastro-oesophageal-reflux-disease/)

Educational information, not medical advice. For any symptom, see a health professional.

Sources: [Insomnia](https://medlineplus.gov/ency/article/000805.htm) (MedlinePlus (U.S. National Library of Medicine), 2025); [Insomnia](https://www.nhlbi.nih.gov/health/insomnia) (National Heart, Lung, and Blood Institute (NHLBI), 2025).

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Source: https://durgical.com/en/conditions/insomnia-disorder/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/conditions/insomnia-disorder/