Insomnia is one of the most common sleep disorders worldwide, characterised by persistent difficulty initiating sleep, maintaining sleep, or waking earlier than desired despite adequate opportunity for rest. It affects both physical and psychological wellbeing and can significantly impair daily functioning. According to the World Health Organization (WHO, 2023) and epidemiological reviews, between 10% and 30% of adults experience chronic insomnia symptoms, with higher rates among women and older adults (Morin and Benca, 2012).
This article explores the definition, causes, symptoms and evidence-based treatments of insomnia, drawing upon textbooks, peer-reviewed journal articles and reputable health organisations, using the Harvard referencing system and British spelling.
1.0 Understanding Insomnia
Insomnia is classified as either acute (short-term) or chronic (long-term). Acute insomnia may last days or weeks, often triggered by stress or life events. Chronic insomnia persists for at least three nights per week for three months or longer (American Academy of Sleep Medicine, 2014).
The International Classification of Sleep Disorders (ICSD-3) defines insomnia as a disorder involving difficulty sleeping accompanied by daytime impairment, such as fatigue, reduced concentration or mood disturbance (American Academy of Sleep Medicine, 2014).
2.0 Symptoms of Insomnia
The symptoms of insomnia extend beyond night-time sleep difficulty. They include both nocturnal and daytime manifestations.
2.1 Night-Time Symptoms
- Difficulty falling asleep (sleep onset insomnia)
- Frequent awakenings during the night
- Early morning awakening
- Non-restorative sleep
For example, an individual may lie awake for over an hour before falling asleep and then wake repeatedly throughout the night.
2.2 Daytime Symptoms
- Persistent fatigue
- Irritability
- Difficulty concentrating
- Memory impairment
- Reduced work performance
- Increased risk of accidents
Sleep deprivation affects cognitive processing and emotional regulation. Walker (2017) explains that inadequate sleep heightens amygdala activity, increasing emotional reactivity and stress sensitivity.
3.0 Causes of Insomnia
Insomnia arises from a complex interaction of biological, psychological and environmental factors.
3.1 Psychological Causes
Stress is one of the most common triggers of insomnia. According to Morin and Benca (2012), anxiety and rumination create a state of cognitive hyperarousal, preventing the brain from transitioning into sleep.
Depression is strongly associated with insomnia. Sleep disturbance is both a symptom and risk factor for mood disorders (Riemann et al., 2017).
For example, a person experiencing workplace stress may replay conversations repeatedly at bedtime, delaying sleep onset.
3.2 Behavioural and Lifestyle Factors
Poor sleep hygiene contributes significantly to insomnia. Common behaviours include:
- Irregular sleep schedules
- Excessive screen time before bed
- Late caffeine consumption
- Inadequate sleep environment
The NHS (2023) advises maintaining consistent bedtime routines and limiting electronic device use in the evening.
3.3 Medical Conditions
Insomnia may result from underlying medical conditions such as:
- Chronic pain
- Asthma
- Gastro-oesophageal reflux disease
- Hyperthyroidism
- Neurological disorders
Sleep apnoea and restless legs syndrome may also mimic or worsen insomnia symptoms (Kryger, Roth and Dement, 2017).
3.4 Medication and Substance Use
Certain medications, including corticosteroids and stimulants, may disrupt sleep. Alcohol, although initially sedating, interferes with REM sleep and may cause night-time awakenings (Kryger, Roth and Dement, 2017).
3.5 Circadian Rhythm Disruption
Shift work, jet lag and inconsistent schedules can disrupt the body’s circadian rhythm, impairing melatonin release and sleep timing.
4.0 The Impact of Chronic Insomnia
Chronic insomnia is associated with increased risk of:
- Cardiovascular disease
- Hypertension
- Type 2 diabetes
- Depression and anxiety disorders
- Impaired immune function
Grandner (2017) highlights that persistent short sleep duration is linked with metabolic dysregulation and inflammation.
For example, individuals sleeping fewer than six hours per night over prolonged periods demonstrate elevated cardiovascular risk markers.
5.0 Treatment of Insomnia
Treatment depends on underlying causes and symptom severity. Evidence-based approaches prioritise non-pharmacological interventions.
5.1 Cognitive Behavioural Therapy for Insomnia (CBT-I)
CBT-I is considered the gold standard treatment for chronic insomnia (Riemann et al., 2017). It addresses maladaptive thoughts and behaviours related to sleep.
CBT-I typically includes:
- Sleep restriction therapy
- Stimulus control therapy
- Cognitive restructuring
- Relaxation techniques
For example, stimulus control involves using the bed only for sleep and intimacy, avoiding television or phone use in bed.
Meta-analyses show CBT-I significantly improves sleep onset latency and sleep efficiency (Morin and Benca, 2012).
5.2 Sleep Hygiene Education
Improving sleep hygiene can reduce mild insomnia symptoms. Recommendations include:
- Going to bed and waking at the same time daily
- Creating a cool, dark and quiet bedroom
- Avoiding caffeine after mid-afternoon
- Limiting daytime naps
- Engaging in regular physical activity
The NHS (2023) emphasises consistency and routine in promoting circadian alignment.
5.3 Relaxation Techniques
Relaxation methods such as progressive muscle relaxation, mindfulness meditation and controlled breathing reduce physiological arousal (Kryger, Roth and Dement, 2017).
These techniques are particularly beneficial for stress-related insomnia.
5.4 Pharmacological Treatment
Short-term use of hypnotic medications may be appropriate in selected cases. However, long-term reliance is discouraged due to risks of dependency, tolerance and residual sedation (Riemann et al., 2017).
Melatonin supplements may benefit individuals with circadian rhythm disorders but are less effective for chronic primary insomnia.
5.5 Addressing Underlying Conditions
Effective management of chronic pain, mental health disorders or medical conditions may resolve secondary insomnia.
6.0 When to Seek Medical Advice
Medical consultation is recommended if:
- Insomnia persists longer than three months
- Daytime functioning is significantly impaired
- There are signs of depression or anxiety
- Snoring or breathing interruptions suggest sleep apnoea
Early intervention improves long-term outcomes.
Insomnia is a prevalent and potentially debilitating sleep disorder characterised by difficulty initiating or maintaining sleep alongside daytime impairment. Its causes are multifactorial, encompassing psychological stress, behavioural habits, medical conditions and circadian disruption.
While short-term insomnia is common during stressful periods, chronic insomnia requires structured intervention. Evidence strongly supports cognitive behavioural therapy for insomnia (CBT-I) as the most effective long-term treatment, complemented by sleep hygiene and relaxation techniques.
Sleep is a fundamental biological process essential for mental clarity, emotional balance and physical health. Recognising symptoms early and implementing appropriate strategies can restore healthy sleep patterns and improve overall wellbeing.
References
American Academy of Sleep Medicine (2014) International Classification of Sleep Disorders. 3rd edn. Darien, IL: AASM.
Grandner, M.A. (2017) ‘Sleep, health and society’, Sleep Medicine Clinics, 12(1), pp. 1–22.
Kryger, M., Roth, T. and Dement, W. (2017) Principles and Practice of Sleep Medicine. 6th edn. Philadelphia: Elsevier.
Morin, C.M. and Benca, R. (2012) ‘Chronic insomnia’, The Lancet, 379(9821), pp. 1129–1141.
NHS (2023) Insomnia. Available at: https://www.nhs.uk/conditions/insomnia/ (Accessed: 17 February 2026).
Riemann, D., Baglioni, C., Bassetti, C. et al. (2017) ‘European guideline for the diagnosis and treatment of insomnia’, Journal of Sleep Research, 26(6), pp. 675–700.
Walker, M. (2017) Why We Sleep. London: Penguin.
