Sleep Disorders: By the Numbers

Sleep disorders represent one of the most prevalent — and most underrecognised — public health challenges of the modern era. The data paints a striking picture: hundreds of millions of people worldwide are sleeping poorly, most do not have a diagnosis, and the economic, social, and health costs are measured in billions of dollars and hundreds of thousands of lives.

How Much Sleep Are People Getting?

Adults are recommended to get 7–9 hours of sleep per night. The reality falls consistently short of this:

• Approximately 35% of US adults report regularly sleeping fewer than 7 hours per night (CDC, 2016)
• In the UK, a 2017 survey found that 67% of adults suffer from disrupted sleep, with 23% getting no more than 5 hours per night
• Average sleep duration has declined by an estimated 1–2 hours over the past century as industrialisation, artificial light, and now digital devices have compressed sleep
• Adolescents are particularly affected: 73% of high school students in the US do not get the recommended 8–10 hours (CDC, 2015)

Sleep insufficiency rates vary by demographics. Socioeconomic disadvantage, racial and ethnic disparities, and demanding work patterns all independently predict shorter sleep duration. Workers in essential industries — healthcare, transportation, emergency services — show among the highest rates of insufficient sleep.

Prevalence of Insomnia

• 30–35% of the general adult population report symptoms of insomnia (difficulty falling asleep, staying asleep, or unrefreshing sleep)
• 10–15% meet the full criteria for chronic insomnia disorder (symptoms at least 3 nights per week for at least 3 months with daytime impairment)
• Women are approximately 1.5 times more likely than men to have insomnia, a gap that widens at menopause
• Prevalence increases with age: insomnia affects approximately 30–48% of older adults (over 60)
• Insomnia is the most common sleep complaint presenting in primary care
• Despite this, an estimated 60–80% of insomnia cases in primary care are not formally identified or treated

Prevalence of Obstructive Sleep Apnea

OSA is the most common sleep-related medical disorder and its global prevalence is striking:

• An estimated 936 million adults aged 30–69 have mild-to-severe OSA globally (Benjafield et al., The Lancet, 2019)
• Approximately 425 million have moderate-to-severe OSA requiring treatment
• In the United States alone, an estimated 25–30 million adults have OSA
• An estimated 80% of moderate-to-severe OSA cases remain undiagnosed
• Men have OSA at 2–3 times the rate of premenopausal women; post-menopausal women approach male rates
• OSA prevalence has increased substantially over the past three decades, driven largely by rising obesity rates
• In people with type 2 diabetes, OSA prevalence may be as high as 70–80%

Prevalence of Other Common Sleep Disorders

• Restless Legs Syndrome: Affects 5–10% of adults in Western populations; 2–3% have symptoms severe enough to significantly impair sleep and quality of life; women are more commonly affected than men
• Narcolepsy: Affects approximately 1 in 2,000 people (0.05% of the population); average time from symptom onset to diagnosis is 10–15 years in many countries
• Delayed Sleep Phase Disorder: Affects approximately 0.17% of the general population but may affect up to 7–16% of adolescents and young adults
• Parasomnias: Sleepwalking affects approximately 1–3% of adults; sleep terrors affect up to 6% of children at some point; REM sleep behaviour disorder affects approximately 0.5% of adults, rising to 2% in older adults
• Periodic Limb Movement Disorder: Prevalence increases strongly with age, affecting approximately 5% of adults aged 30–50 and up to 44% of adults over 65

The Economic Cost of Poor Sleep

The economic burden of sleep disorders and sleep insufficiency is enormous and spans multiple domains:

• A 2016 RAND Corporation analysis estimated that sleep insufficiency costs the US economy $411 billion per year in lost productivity — approximately 2.28% of GDP
• Similar analyses found costs of £40 billion in the UK and €60 billion in Germany annually
• Direct healthcare costs attributable to sleep disorders in the US exceed $16 billion per year
• Untreated OSA is associated with significantly elevated healthcare utilisation — an estimated 2–3 times higher in patients before diagnosis compared to matched controls

Sleep Disorders and Road Safety

Drowsy driving is one of the most serious public health consequences of sleep disorders and insufficient sleep:

• The US National Highway Traffic Safety Administration (NHTSA) estimates drowsy driving causes approximately 91,000 crashes per year, resulting in approximately 800 deaths annually — though actual figures are believed to be significantly higher due to underreporting
• People with untreated OSA have a road accident risk 2–7 times higher than the general driving population
• Driving after 20 hours without sleep produces impairment equivalent to a blood alcohol level of 0.08% — the legal limit in most countries
• Treatment of OSA with CPAP reduces accident risk to near-normal levels within weeks

Sleep Disorders and Mental Health

• Approximately 75% of people with major depressive disorder experience insomnia; 40% have hypersomnia
• Chronic insomnia multiplies the risk of developing a new major depressive episode by approximately 5-fold
• People with chronic insomnia are 17 times more likely to have clinically significant anxiety
• Treating insomnia produces measurable improvements in depression and anxiety symptoms — in some studies, sleep improvement mediates a significant proportion of antidepressant effect
• PTSD has an estimated insomnia prevalence of 70–91%, making it the most sleep-disrupted psychiatric condition

Trends Over Time

Several trends make the sleep disorder landscape more — not less — pressing over time:

• Rising global obesity rates are driving increases in OSA prevalence worldwide
• Ageing populations increase the burden of age-related sleep disorders (insomnia, PLMD, circadian disruption)
• Increased shift work and 24-hour economy patterns are expanding the number of people with circadian misalignment
• Smartphone and digital device use has extended artificial light exposure into the sleeping environment, systematically delaying melatonin onset for a large proportion of the population
• Awareness and diagnostic capacity are improving — but still fall far short of the scale of unmet need

References

• Benjafield AV, et al. Estimation of the global prevalence of sleep apnea. The Lancet Respiratory Medicine. 2019;7(8):687–698.
• Hafner M, et al. Why sleep matters — the economic costs of insufficient sleep. RAND Corporation. 2016.
• Centers for Disease Control and Prevention. Sleep and Sleep Disorders: Data and Statistics. 2023.
• Ohayon MM. Prevalence and comorbidity of sleep disorders in the general population. Sleep Medicine Reviews. 2002;6(2):97–111.
• National Highway Traffic Safety Administration (NHTSA). Traffic Safety Facts: Drowsy Driving. 2017.