Insomnia & Sleep Disorders
Symptoms, Causes & Treatment
Everything you need to know about insomnia and sleep disorders: what causes them, how they are assessed, and the most effective treatments available.
What Are Insomnia & Sleep Disorders?
Sleep is a fundamental biological necessity, as essential to health as nutrition and physical activity. Adults require 7–9 hours of sleep per night for optimal physical and mental functioning. Chronic insufficient or poor-quality sleep is associated with a significantly increased risk of cardiovascular disease, obesity, type 2 diabetes, impaired immune function, depression, anxiety, and cognitive decline.
Insomnia is the most common sleep disorder, characterised by persistent difficulty falling asleep, staying asleep, or waking too early, despite adequate opportunity for sleep, and leading to significant daytime impairment. It affects approximately one in three adults in the UK at any given time, with around 10–15% experiencing chronic insomnia – defined as occurring at least three nights per week for at least three months.
Beyond insomnia, a range of other sleep disorders can significantly affect health and quality of life:
Obstructive Sleep Apnoea (OSA) – repeated partial or complete obstruction of the upper airway during sleep, causing brief awakenings, oxygen desaturation, and profoundly unrefreshing sleep. It is strongly associated with obesity, hypertension, cardiovascular disease, and type 2 diabetes. Highly prevalent and frequently undiagnosed.
Restless Legs Syndrome (RLS) – an uncomfortable urge to move the legs, typically worse in the evening and at night, which significantly disrupts sleep onset.
Narcolepsy – a neurological condition characterised by excessive daytime sleepiness, sudden muscle weakness (cataplexy), sleep paralysis, and hypnagogic hallucinations.
Parasomnias – abnormal behaviours during sleep, including sleepwalking, sleep terrors, REM sleep behaviour disorder (acting out dreams), and sleep paralysis.
Circadian Rhythm Disorders – disruptions to the body's internal clock, including delayed sleep phase disorder (characteristically presenting in adolescents) and shift work disorder.
What Are the Symptoms of Insomnia & Sleep Disorders?
Symptoms vary depending on the type of sleep disorder. Insomnia and sleep apnoea are the most common, but several other distinct conditions also affect sleep quality and daytime functioning.
- Difficulty falling asleep at bedtime (sleep onset insomnia)
- Waking frequently during the night
- Waking too early and being unable to return to sleep
- Unrefreshing or non-restorative sleep
- Daytime fatigue, low energy, and irritability
- Difficulty concentrating or poor memory during the day
- Anxiety or worry about sleep itself
- Symptoms present at least three nights per week for at least three months (chronic insomnia)
- Loud snoring, gasping, or choking during sleep (sleep apnoea)
- Excessive daytime sleepiness despite adequate time in bed
- Irresistible urge to move legs at rest, especially evenings (restless legs syndrome)
- Sudden episodes of muscle weakness triggered by emotion (cataplexy — narcolepsy)
- Sleepwalking, night terrors, or acting out dreams (parasomnias)
- Extreme difficulty waking at conventional times; delayed sleep phase disorder
- Bed partner reports breathing pauses during sleep
Seek prompt clinical assessment if you or a bed partner witnesses pauses in breathing during sleep, if excessive daytime sleepiness is so severe that it is affecting safety (including driving), if sleep disorder symptoms are accompanied by depression or thoughts of self-harm, or if symptoms are significantly worsening despite good sleep hygiene. Do not attempt to manage these presentations with over-the-counter remedies alone.
What Causes Insomnia & Sleep Disorders?
Sleep disorders rarely have a single cause. Most cases of chronic insomnia involve a combination of predisposing factors (genetic vulnerability, anxious temperament), precipitating events (stress, illness, life change), and perpetuating behaviours (poor sleep habits, time in bed, daytime napping) that maintain the problem long after the original trigger has resolved.
Anxiety, depression, PTSD, and other mental health conditions are among the most common causes of insomnia. Racing thoughts, hyperarousal, and rumination at bedtime keep the brain in a state of alertness incompatible with sleep onset and maintenance.
Poor sleep hygiene — including irregular sleep schedules, excessive screen use before bed, napping during the day, and using the bed for activities other than sleep — disrupts the body’s circadian rhythm and trains the brain to associate the bed with wakefulness.
Chronic pain, respiratory conditions (including asthma and COPD), heart failure, acid reflux, overactive thyroid, and many other medical conditions can fragment sleep. Sleep apnoea — where breathing repeatedly stops during sleep — is a major and frequently undiagnosed cause of poor sleep quality.
Caffeine (which has a half-life of 5–6 hours), alcohol (which fragments sleep in the second half of the night), nicotine, and many medications — including corticosteroids, SSRIs, beta-blockers, and decongestants — can disrupt sleep onset, architecture, and duration.
Shift work, jet lag, and irregular schedules disrupt the body’s internal clock (circadian rhythm), misaligning the sleep-wake cycle with environmental light cues. Chronic circadian misalignment increases the risk of insomnia, mood disorders, and metabolic disease.
Noise, light, an uncomfortable mattress or room temperature, and sharing a bed with a partner who snores or moves frequently are environmental factors that significantly impair sleep quality and are often overlooked in clinical assessment.
Key Risk Factors
How Are Sleep Disorders Diagnosed?
Most sleep disorders are diagnosed clinically based on a detailed sleep history, symptom pattern, and impact on daytime functioning. A two-week sleep diary is usually requested before or at the first appointment. Investigations are guided by the suspected diagnosis and may include blood tests to exclude medical causes or a sleep study for suspected sleep apnoea or narcolepsy.
How Are Insomnia & Sleep Disorders Treated?
Treatment depends on the type and underlying cause of the sleep disorder. For insomnia, CBT-I is first-line and more effective long-term than medication. For sleep apnoea, CPAP therapy is the gold standard. For circadian rhythm disorders, light therapy and melatonin play a key role. A clinician can assess your specific presentation and recommend the most appropriate treatment pathway.
Supportive Measures
Alongside formal treatment, a number of self-help measures support better sleep. Keeping a consistent sleep and wake schedule, even at weekends, is the most impactful single habit. Avoiding lying awake in bed for long periods — getting up after 20 minutes if awake and doing something calm until sleepy — helps break the association between bed and wakefulness. Relaxation techniques such as progressive muscle relaxation, guided imagery, or body scanning can reduce physiological arousal at bedtime. Reducing alcohol intake — which fragments sleep in the second half of the night despite initially promoting sleep onset — is also important.
CBT for Insomnia (CBT-I) — The Gold Standard Treatment
CBT for Insomnia (CBT-I) is the most effective long-term treatment for chronic insomnia and is recommended as first-line by NICE and SIGN. It is more effective than sleeping tablets in the long term, produces no dependence, and its benefits are maintained after treatment ends. CBT-I typically involves sleep restriction, stimulus control, cognitive restructuring of unhelpful beliefs about sleep, and relaxation training. It is available via IAPT (self-referral), sleep clinics, or digitally via validated apps such as Sleepio. If your insomnia has not responded to sleep hygiene alone, CBT-I is the next step.
When Should You Seek Medical Advice for Sleep Problems?
Excessive daytime sleepiness is causing dangerous situations such as falling asleep while driving · A sleep disorder is accompanied by thoughts of self-harm or suicide · Sleepwalking or parasomnia episodes are placing the person at risk of physical injury.
You have had significant sleep difficulties for more than three months · Poor sleep is affecting your ability to work, concentrate, or function safely · A bed partner has witnessed pauses in breathing or severe snoring · You are relying on alcohol, over-the-counter remedies, or sleeping tablets long-term · Sleep difficulties are accompanied by depression, anxiety, or other mental health symptoms · You need a referral for CBT-I or a sleep clinic assessment.
How Can You Improve & Protect Your Sleep?
While not all sleep disorders can be prevented, the majority of insomnia cases are significantly influenced by behaviours and habits that can be modified. Good sleep hygiene provides a strong foundation for healthy sleep and can prevent short-term sleep difficulties from becoming chronic.
Going to bed and waking at the same time every day — including weekends — is the single most powerful sleep hygiene measure. Consistency anchors the circadian rhythm and strengthens the natural sleep drive, making it easier to fall asleep and stay asleep.
Avoiding screens for at least one hour before bed reduces blue light exposure, which suppresses melatonin production. Using night mode, blue light glasses, or switching to a book or podcast instead supports natural sleep onset.
Caffeine has a half-life of 5–6 hours — a coffee at 4pm still has half its caffeine active at 10pm. Cutting off caffeine by early afternoon and limiting alcohol (which disrupts sleep architecture) significantly improves sleep quality.
A cool (16–18°C), dark, and quiet bedroom strongly promotes sleep. Blackout curtains, earplugs or white noise, and a comfortable mattress are simple investments that can transform sleep quality.
Using the bed only for sleep (and sex) trains the brain to associate the bedroom with sleep rather than wakefulness. Working, watching TV, or scrolling in bed undermines this association and is one of the most common perpetuating factors in chronic insomnia.
Regular physical activity — particularly aerobic exercise — significantly improves sleep onset, duration, and quality. Avoid vigorous exercise within two to three hours of bedtime, as this can delay sleep onset in some people.
Speak to a Clinician About Sleep Problems
Poor sleep should not be accepted as normal. Through The GP Service, you can speak to a licensed clinician in minutes — from home. A clinician can assess your sleep difficulties, arrange appropriate investigations, and recommend or prescribe the most effective treatment for your situation — whether that is a referral for CBT-I, a prescription for melatonin, or investigation for sleep apnoea.
Expert clinical advice, when you need it.
Insomnia & Sleep Disorder FAQs
Adults need seven to nine hours of sleep per night on average. However, there is genuine individual variation — some people function well on slightly less, and a small proportion genuinely need more. The key indicator is daytime functioning: if you feel alert, well, and able to concentrate without caffeine, you are likely getting enough sleep. Consistently needing an alarm, feeling drowsy during the day, or relying on weekend lie-ins to ‘catch up’ are signs of chronic insufficient sleep.
Chronic insomnia is defined as difficulty falling asleep, staying asleep, or achieving restorative sleep on at least three nights per week, for at least three months, causing daytime impairment. It affects approximately 10–15% of adults. Cognitive Behavioural Therapy for Insomnia (CBT-I) is the most effective long-term treatment and is recommended as first-line by NICE. Unlike sleep medication, CBT-I addresses the underlying thought patterns and behaviours maintaining insomnia and produces durable improvements without dependence risk.
Sleep apnoea is a common condition — affecting approximately 1.5 million adults in the UK, though many are undiagnosed — in which the airway repeatedly collapses during sleep, causing brief pauses in breathing. This fragments sleep and causes significant daytime sleepiness. Key warning signs include loud snoring, witnessed breathing pauses, waking with a dry mouth or headache, and excessive daytime sleepiness. If you or a partner notices these signs, a sleep study is warranted. Treatment with CPAP (continuous positive airway pressure) is highly effective.
Sleeping tablets — including Z-drugs (zopiclone, zolpidem) and benzodiazepines — are associated with significant risks including dependence, tolerance, rebound insomnia on stopping, daytime sedation, falls (particularly in older adults), and impaired driving. NICE does not recommend them for chronic insomnia. They may be appropriate for very short-term use (two to four weeks) in severe acute insomnia while other treatments are initiated. Melatonin is a safer option for certain presentations and age groups. A clinician can advise on the most appropriate approach for your circumstances.
Waking in the early hours (typically between 3 and 5am) and being unable to return to sleep is a classic symptom of depression. Other common sleep disturbances in depression include difficulty falling asleep due to rumination, and in some cases — particularly in atypical depression or bipolar disorder — excessive sleeping. If early morning waking is accompanied by low mood, loss of interest, or other depressive symptoms, a clinical assessment for depression is warranted. Treating the depression typically improves sleep significantly.
Short naps of 10–20 minutes can improve alertness and mood without significantly affecting night-time sleep. However, napping for longer than 30 minutes — particularly in the afternoon — can reduce sleep pressure (the drive to sleep) and make it harder to fall asleep at night. For people with insomnia, napping is generally discouraged as it relieves sleepiness without addressing the underlying sleep deficit in a way that supports night-time consolidation. If you cannot function without napping, this suggests insufficient night-time sleep and warrants investigation.
Sleep quality typically changes with age. Older adults tend to experience a shift in circadian timing (becoming sleepier earlier in the evening and waking earlier in the morning), reduced deep slow-wave sleep, more frequent brief awakenings, and greater sensitivity to environmental disruption. These changes are normal. However, they can be compounded by medical conditions, medications, pain, and mental health issues that are more prevalent in later life. Significant sleep disturbance is not an inevitable part of ageing and warrants clinical assessment if it is affecting quality of life.
Restless Legs Syndrome (RLS) is a neurological condition characterised by an irresistible urge to move the legs, usually accompanied by uncomfortable sensations (described as crawling, itching, or aching), which worsen at rest and are partially or fully relieved by movement. Symptoms are typically worse in the evening and at night, significantly disrupting sleep onset. RLS affects approximately 5–10% of adults. It can be primary (idiopathic) or secondary to iron deficiency, pregnancy, kidney disease, or certain medications. Treatment includes iron supplementation (if deficient), lifestyle measures, and in severe cases, prescription medication.