How common are sleep disorders?

Approximately 45% of the global population has sleep problems in some form. Obstructive sleep apnoea (OSA) — the most prevalent diagnosable sleep disorder — affects 936 million people aged 30-69 globally, of whom >50% are undiagnosed. Insomnia disorder (persistent sleep difficulties with daytime consequences) affects 10-15% of adults. Restless legs syndrome affects approximately 5-10% of adults. Circadian rhythm disorders, narcolepsy and parasomnias affect smaller but significant numbers.

What is insomnia and how is it treated?

Insomnia disorder is persistent difficulty initiating or maintaining sleep (or early morning awakening) with significant daytime consequences (fatigue, concentration difficulties, mood changes, reduced performance) — not explained by another condition. Cognitive behavioural therapy for insomnia (CBT-I) is the gold-standard first-line treatment — more effective than sleeping pills long-term, with sustained benefits and no withdrawal risk. CBT-I components: sleep restriction therapy (building sleep drive); stimulus control (associating bed only with sleep); cognitive restructuring (addressing unhelpful beliefs about sleep); and sleep hygiene.

What are the health consequences of poor sleep?

Chronic sleep deprivation (<7 hours per night) increases risk of: obesity (disrupted hunger hormones — leptin and ghrelin); type 2 diabetes (impaired glucose tolerance); cardiovascular disease (hypertension, heart attack, stroke); depression and anxiety; immune dysfunction; cognitive impairment and dementia; and cancer (through circadian disruption and immune suppression). Shift work — the most common cause of circadian disruption — is classified as a Group 2A carcinogen by IARC.

Does sleep apnoea cause cardiovascular disease?

OSA is an independent risk factor for cardiovascular disease — causing hypertension (present in 50-60% of OSA patients), atrial fibrillation, heart failure, stroke and coronary artery disease through: nocturnal hypoxia; sympathetic nervous system activation; oxidative stress; systemic inflammation; and endothelial dysfunction. CPAP treatment reduces blood pressure and improves cardiovascular risk factors, though randomised trials have not shown clear reduction in cardiovascular events (partly reflecting difficulty achieving consistent CPAP adherence in trials).

Cognitive Behavioural Therapy for Insomnia (CBT-I) is a structured psychological therapy — the gold-standard first-line treatment for chronic insomnia. Unlike sleeping pills, CBT-I addresses the underlying thoughts and behaviours maintaining insomnia and achieves sustained remission in 60-80% of patients. Components: sleep restriction (temporarily limiting time in bed to build sleep drive); stimulus control (using bed only for sleep and sex); cognitive restructuring (challenging catastrophic thoughts about sleep); relaxation techniques; and sleep hygiene education. Digital CBT-I apps (Sleepio, Somryst) expand access.

Are sleeping pills safe for insomnia?

Short-term use of sleep medications — benzodiazepines, Z-drugs (zolpidem, zopiclone) — provides relief for acute insomnia but is not recommended for chronic insomnia due to: tolerance (effectiveness decreasing over time); dependency; withdrawal symptoms; cognitive impairment; falls risk in older adults; rebound insomnia on stopping; and increased mortality in long-term users. Low-dose doxylamine (antihistamine) and melatonin have more benign profiles for short-term use. Orexin receptor antagonists (suvorexant, lemborexant) are newer options with better safety profiles.

What is shift work sleep disorder?

Shift work sleep disorder affects people whose work schedules conflict with the natural circadian rhythm — causing insomnia at conventional sleep times and excessive sleepiness during work hours. Approximately 20% of the workforce in high-income countries does shift work. Consequences: sleep deprivation; accidents and errors; cardiovascular disease; metabolic syndrome; gastrointestinal disorders; mental health problems; and — from chronic circadian disruption — IARC Group 2A carcinogenicity. Management: strategic napping; light therapy; melatonin; modafinil for night shift workers.

Narcolepsy is a rare (approximately 1 in 2,000) neurological disorder characterised by: excessive daytime sleepiness (irresistible sleep attacks); cataplexy (sudden muscle weakness triggered by strong emotions like laughter — present in type 1 narcolepsy); sleep paralysis; and hypnagogic hallucinations. Type 1 narcolepsy is caused by autoimmune destruction of orexin (hypocretin)-producing neurons in the hypothalamus. Treated with: modafinil for sleepiness; sodium oxybate (GHB) for cataplexy and sleepiness; and lifestyle adjustments (strategic napping).

How does sleep affect cognitive function and dementia risk?

Chronic sleep deprivation impairs attention, memory consolidation, executive function and emotional regulation. Sleep is when the glymphatic system clears metabolic waste — including amyloid beta and tau proteins — from the brain. Poor sleep is associated with increased amyloid accumulation and is an independent risk factor for Alzheimer's disease and cognitive decline. Treating sleep disorders (particularly OSA) may reduce dementia risk — though evidence is still developing. The Lancet Commission on Dementia Prevention (2024) includes poor sleep as a modifiable risk factor.

How does GMJ News cover sleep disorders?

GMJ News covers WHO sleep health priorities, CBT-I evidence, OSA prevalence and CPAP therapy, shift work health effects, drowsy driving and sleep-cardiovascular links. Sleep disorders are relevant to Georgian public health — particularly occupational sleep disruption, road safety and the dementia-sleep connection — and to PHIG's health promotion work.

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Sleep Disorders

Q: What is obstructive sleep apnoea?

OSA occurs when the upper airway repeatedly collapses during sleep, causing brief pauses in breathing (apnoeas), oxygen desaturation and brief arousal. Symptoms: loud snoring; witnessed breathing pauses; gasping; fragmented sleep; and — the defining feature — excessive daytime sleepiness. Risk factors: obesity (the most important — fat deposits narrow the airway); male sex; older age; large neck circumference; alcohol. Diagnosed by polysomnography (sleep study) or home sleep testing. Treated with CPAP — a device maintaining positive airway pressure to keep the airway open.

Q: Does sleep apnoea cause cardiovascular disease?

OSA is an independent risk factor for cardiovascular disease — causing hypertension (present in 50-60% of OSA patients), atrial fibrillation, heart failure, stroke and coronary artery disease through: nocturnal hypoxia; sympathetic nervous system activation; oxidative stress; systemic inflammation; and endothelial dysfunction. CPAP treatment reduces blood pressure and improves cardiovascular risk factors, though randomised trials have not shown clear reduction in cardiovascular events (partly reflecting difficulty achieving consistent CPAP adherence in trials).

Q: What is CBT-I?

Cognitive Behavioural Therapy for Insomnia (CBT-I) is a structured psychological therapy — the gold-standard first-line treatment for chronic insomnia. Unlike sleeping pills, CBT-I addresses the underlying thoughts and behaviours maintaining insomnia and achieves sustained remission in 60-80% of patients. Components: sleep restriction (temporarily limiting time in bed to build sleep drive); stimulus control (using bed only for sleep and sex); cognitive restructuring (challenging catastrophic thoughts about sleep); relaxation techniques; and sleep hygiene education. Digital CBT-I apps (Sleepio, Somryst) expand access.

Q: Are sleeping pills safe for insomnia?

Short-term use of sleep medications — benzodiazepines, Z-drugs (zolpidem, zopiclone) — provides relief for acute insomnia but is not recommended for chronic insomnia due to: tolerance (effectiveness decreasing over time); dependency; withdrawal symptoms; cognitive impairment; falls risk in older adults; rebound insomnia on stopping; and increased mortality in long-term users. Low-dose doxylamine (antihistamine) and melatonin have more benign profiles for short-term use. Orexin receptor antagonists (suvorexant, lemborexant) are newer options with better safety profiles.

Q: What is shift work sleep disorder?

Shift work sleep disorder affects people whose work schedules conflict with the natural circadian rhythm — causing insomnia at conventional sleep times and excessive sleepiness during work hours. Approximately 20% of the workforce in high-income countries does shift work. Consequences: sleep deprivation; accidents and errors; cardiovascular disease; metabolic syndrome; gastrointestinal disorders; mental health problems; and — from chronic circadian disruption — IARC Group 2A carcinogenicity. Management: strategic napping; light therapy; melatonin; modafinil for night shift workers.

Q: What is narcolepsy?

Narcolepsy is a rare (approximately 1 in 2,000) neurological disorder characterised by: excessive daytime sleepiness (irresistible sleep attacks); cataplexy (sudden muscle weakness triggered by strong emotions like laughter — present in type 1 narcolepsy); sleep paralysis; and hypnagogic hallucinations. Type 1 narcolepsy is caused by autoimmune destruction of orexin (hypocretin)-producing neurons in the hypothalamus. Treated with: modafinil for sleepiness; sodium oxybate (GHB) for cataplexy and sleepiness; and lifestyle adjustments (strategic napping).

Q: How does sleep affect cognitive function and dementia risk?

Chronic sleep deprivation impairs attention, memory consolidation, executive function and emotional regulation. Sleep is when the glymphatic system clears metabolic waste — including amyloid beta and tau proteins — from the brain. Poor sleep is associated with increased amyloid accumulation and is an independent risk factor for Alzheimer's disease and cognitive decline. Treating sleep disorders (particularly OSA) may reduce dementia risk — though evidence is still developing. The Lancet Commission on Dementia Prevention (2024) includes poor sleep as a modifiable risk factor.

GMJ News knowledge hub · last reviewed September 2026 · Georgian Medical Journal

Summary Statistics Glossary GMJ news FAQ Documents Organizations Research

Sleep disorders affect an estimated 45% of the global population, with insomnia disorder (persistent difficulty initiating or maintaining sleep with daytime consequences) affecting approximately 10-15% of adults, and obstructive sleep apnoea (OSA) affecting an estimated 936 million people aged 30-69 (WHO/Lancet). Inadequate sleep drives cardiovascular disease, metabolic disorders, mental health conditions, road traffic accidents and reduced cognitive performance — yet sleep medicine is severely neglected in most health systems globally. Cognitive behavioural therapy for insomnia (CBT-I) is the evidence-based first-line treatment, more effective than sleep medications long-term, and increasingly available through digital platforms.

Key messages

45% of global population affected

Sleep disorders affect approximately 45% of the global population in some form. Insomnia disorder (persistent difficulty sleeping with daytime consequences) affects 10-15% of adults; obstructive sleep apnoea affects an estimated 936 million people aged 30-69 (WHO/Lancet).

CBT-I is gold standard

Cognitive behavioural therapy for insomnia (CBT-I) is more effective than sleep medications long-term — achieving remission in 60-80% of patients — yet is rarely offered as first-line care. CBT-I is now available via digital platforms, expanding access.

Sleep apnoea is undertreated

Obstructive sleep apnoea (OSA) — where repeated airway collapse during sleep causes oxygen desaturation — is severely underdiagnosed. OSA causes cardiovascular disease, metabolic syndrome, road traffic accidents and neurocognitive impairment. CPAP therapy is highly effective.

Sleep deprivation health effects

Chronic sleep deprivation (less than 7 hours per night) increases risk of obesity, type 2 diabetes, cardiovascular disease, depression, immune dysfunction and dementia. The WHO sleep deprivation crisis has been described as a public health epidemic.

Road safety link

Drowsy driving causes approximately 20% of serious road traffic accidents — comparable to drink-driving. Sleep disorders (particularly OSA and insomnia) are major contributors to impaired driving and occupational accidents.

WHO global strategy

WHO has highlighted sleep disorders as a global health priority — calling for integration of sleep medicine into primary health care, improved occupational health standards, and public education about sleep hygiene.

Key statistics

45%

of global population with sleep problems

WHO/WASM

936M

people with obstructive sleep apnoea

Benjafield et al. Lancet 2019

10-15%

of adults with insomnia disorder

WHO/research

7hrs

WHO recommended minimum sleep for adults

WHO

20%

of road accidents from drowsy driving

WHO

>50%

of OSA cases undiagnosed

Lancet/WASM

Global prevalence of sleep disorders by type (millions of people) — WHO/research

Source: WHO and published research estimates. Insomnia symptoms very common; OSA is the most prevalent sleep disorder.

Glossary of key terms

Insomnia disorder
WHO/ICD-11/DSM-5Persistent difficulty initiating or maintaining sleep (or early morning awakening), with daytime consequences (fatigue, cognitive impairment, mood disturbance, reduced performance) — not explained by another condition. Affects 10-15% of adults. CBT-I is the gold-standard treatment.

Obstructive sleep apnoea (OSA)
AASM/WHORepeated partial or complete upper airway collapse during sleep — causing apnoeas (breathing pauses), oxygen desaturation and arousal. Characterised by loud snoring, witnessed apnoeas, gasping and excessive daytime sleepiness. Risk factors: obesity, male sex, older age, large neck circumference. Treated with CPAP.

CPAP (continuous positive airway pressure)
AASMThe gold-standard treatment for moderate-severe OSA — a device delivering pressurised air through a mask to keep the upper airway open during sleep. Highly effective: eliminates apnoeas, improves daytime sleepiness, blood pressure and cognitive function. Adherence is the primary challenge.

CBT-I (cognitive behavioural therapy for insomnia)
AASM/NICEThe evidence-based first-line treatment for chronic insomnia — more effective than sleep medications long-term with no withdrawal or dependency issues. Components: sleep restriction therapy; stimulus control; sleep hygiene education; relaxation training; cognitive restructuring.

Circadian rhythm disorders
WHO/ICD-11Misalignment between the internal biological clock and the external environment — including delayed sleep-wake phase disorder (commonly called "night owl"), shift work sleep disorder, jet lag, and free-running circadian rhythm disorder (common in the blind).

Narcolepsy
WHO/ICD-11A rare (affecting approximately 1 in 2,000) neurological sleep disorder characterised by excessive daytime sleepiness, sudden muscle weakness (cataplexy — triggered by emotions), sleep paralysis and hypnagogic hallucinations. Caused by loss of orexin (hypocretin)-producing neurons. Treated with modafinil, stimulants and sodium oxybate.