Sleep disorders and insomnia fall into seven groups in the third edition of the International Classification of Sleep Disorders: insomnia disorders, sleep-related breathing disorders, central disorders of hypersomnolence, circadian rhythm sleep-wake disorders, parasomnias, sleep-related movement disorders and other sleep disorders. Insomnia is the most common: about one third of adults in community surveys report at least one symptom and about 6% meet a diagnosis. Obstructive sleep apnea is estimated to affect 936 million adults aged 30 to 69 worldwide, restless legs syndrome 1.9 to 4.6% of adults depending on definition, and REM sleep behavior disorder about 1% of a middle-aged and older Swiss sample. This page links each group to our articles.
Sleep disorders and insomnia are talked about as if they were one thing. They are not: doctors sort sleep problems into seven groups, and the right next step depends on the group. This page is a hub. It explains the groups in plain words, shows how common each is in the studies we could verify, and links every group to our longer articles.
Nothing here diagnoses anything. If a section sounds like you, use it to describe your nights to a doctor, not to pick a label.
Sleep disorders and insomnia: how doctors sort them
The reference for sorting sleep problems is the International Classification of Sleep Disorders, now in its third edition. A summary of its changes lists seven major categories: insomnia disorders, sleep-related breathing disorders, central disorders of hypersomnolence, circadian rhythm sleep-wake disorders, sleep-related movement disorders, parasomnias, and other sleep disorders. Significant modifications were made to how insomnia, narcolepsy and parasomnias are classified.
Sateia MJ. International classification of sleep disorders-third edition: highlights and modifications. Chest 2014. PMID 25367475
The table puts the seven groups in plain words, with a prevalence figure for each where a population study exists. Different studies use different definitions, so the numbers are a range of what the literature reports, not a ranking of how many people you will meet.
| Group | In plain words | How common (source in the section below) | Our articles |
|---|---|---|---|
| Insomnia disorders | Trouble falling asleep, staying asleep or waking too early, with daytime effects | About 1 in 3 adults have a symptom; about 6% meet a diagnosis | Causes, test, CBT-I |
| Sleep-related breathing disorders | Breathing narrows or stops during sleep; snoring and sleep apnea | Estimated 936 million adults aged 30 to 69 with obstructive sleep apnea | Types of apnea, snoring |
| Central disorders of hypersomnolence | Heavy daytime sleepiness that more sleep does not explain; narcolepsy | Narcolepsy with cataplexy: 25 to 50 per 100,000 | Sleepiness signs, napping |
| Circadian rhythm sleep-wake disorders | The body clock is out of step with the day you need; delayed sleep phase, jet lag, shift work | Delayed sleep phase: 3.3% of 10,220 Norwegian adolescents | Delayed sleep phase, light therapy |
| Parasomnias | Unwanted events around sleep: sleepwalking, night terrors, acting out dreams, nightmares | Confusional arousals 4.2%, night terrors 2.2%, sleepwalking 2.0% in UK adults; REM sleep behavior disorder about 1% | Sleepwalking, RBD, nightmares |
| Sleep-related movement disorders | Urges or movements that interfere with sleep: restless legs, grinding teeth | Restless legs syndrome 1.9 to 4.6% (strict definition) | Restless legs, teeth grinding |
| Other sleep disorders | Conditions that fit nowhere else in the manual | Not given here | See your doctor |
Symptoms overlap, so use this list as a map to the right page, not as a diagnosis. Which group fits what you notice:
- You lie awake, or wake in the night and cannot get back to sleep: insomnia. Start with waking up at night and CBT-I.
- Loud snoring, gasping, pauses someone else saw, morning headaches: breathing. Start with testing for sleep apnea at home.
- Sleepy all day despite enough time in bed: hypersomnolence or a cause behind it. Start with sleep deprivation symptoms.
- You cannot fall asleep until the early hours, or you wake far too early: body clock. Start with delayed sleep phase and waking before the alarm.
- Walking, shouting, acting out dreams, frightening dreams, odd experiences on waking: parasomnia. Start with sleepwalking, waking up confused or nightmares.
- Crawling legs in the evening, jerks, grinding: movement. Start with restless legs syndrome.
Insomnia: the most common sleep condition
Epidemiologists summarizing more than 50 community studies describe four definitions of insomnia with four prevalence figures: about one third of a general population reports at least one symptom, 9 to 15% when daytime consequences are included, 8 to 18% report sleep dissatisfaction, and about 6% meet a diagnosis. Rates are higher in women, and symptoms increase with age. Insomnia is repeatedly linked to major depressive episodes.
Ohayon MM. Epidemiology of insomnia: what we know and what we still need to learn. Sleep Med Rev 2002. PMID 12531146
A Nature Reviews review describes insomnia disorder as dissatisfaction with sleep duration or quality plus difficulty initiating or maintaining sleep, with distress or impaired daytime functioning, often alongside other conditions such as pain and depression. Psychological therapies and some medicines reduce the time to fall asleep and the time awake after sleep onset, and produce a modest increase in sleep time.
Morin CM, Drake CL, Harvey AG, et al. Insomnia disorder. Nat Rev Dis Primers 2015. PMID 27189779
Where to go next: What is insomnia? for the definition and the criteria, What causes insomnia and the insomnia test for the overview, CBT for insomnia explained for the recommended treatment, Why do I keep waking up at night? and 3 a.m. waking for the pattern of waking in the night, Tired but can't sleep, sleep hygiene, medicines that cause insomnia, and the life stages: perimenopause and pregnancy.
Sleep-related breathing disorders: snoring to sleep apnea
These are conditions in which breathing narrows or pauses during sleep. A literature-based analysis estimated that 936 million adults aged 30 to 69 (95% CI 903 to 970 million) have mild to severe obstructive sleep apnea worldwide, and 425 million (399 to 450 million) have moderate to severe. The authors had reliable data from 16 countries and matched the rest. The number was highest in China, followed by the USA, Brazil and India. The study was funded by ResMed, a maker of treatment devices, and used a conversion algorithm to put different studies on one definition.
Benjafield AV, Ayas NT, Eastwood PR, et al. Estimation of the global prevalence and burden of obstructive sleep apnoea: a literature-based analysis. Lancet Respir Med 2019. PMID 31300334
The sleeper often does not notice it. The usual clues are loud snoring, witnessed pauses, gasping, a dry mouth and morning headaches, and daytime sleepiness. Start with Is snoring bad for you? and Types of sleep apnea, then Signs of sleep apnea in women, Can you have sleep apnea without snoring?, Risk factors, Is sleep apnea dangerous? and How to test for sleep apnea at home. If you wake in the night with a gasp or choke, see Waking up gasping for air and Waking up choking at night.
Central disorders of hypersomnolence: when sleepiness is the problem
This group covers heavy daytime sleepiness that a full night does not explain, and narcolepsy is the best-known example. A review of its epidemiology puts the prevalence of narcolepsy with cataplexy between 25 and 50 per 100,000 people, and it points to loss of hypocretin-producing cells in the hypothalamus in genetically susceptible people as the likely cause.
Longstreth WT, Koepsell TD, Ton TG, et al. The epidemiology of narcolepsy. Sleep 2007. PMID 17310860
Most daytime sleepiness is not narcolepsy. Short sleep, sleep apnea, medicines, mood problems and shifted schedules are far more common, so the practical first step is to rule those out. Our pages here are Sleep deprivation symptoms, Heavy sleepers, Sleep inertia and Is napping bad for you?. Sleepiness while driving, or sudden sleep attacks, are reasons to see a doctor promptly.
Circadian rhythm disorders: a body clock out of step
Here sleep itself is fine, but its timing does not fit your life: a clock that runs late, runs early, or is repeatedly shifted by travel or shift work. In a Norwegian population study of 10,220 adolescents aged 16 to 18, delayed sleep phase syndrome had a prevalence of 3.3% (3.7% in girls, 2.7% in boys), and more than half of them also met the criteria for insomnia.
Sivertsen B, Pallesen S, Stormark KM, et al. Delayed sleep phase syndrome in adolescents: prevalence and correlates in a large population based study. BMC Public Health 2013. PMID 24330358
See Delayed sleep phase disorder, Circadian rhythm light therapy, Jet lag and your circadian rhythm, Social jet lag, How to fix your sleep schedule and Why do I always wake up before my alarm?.
Parasomnias: things that happen around sleep
Parasomnias are unwanted events or experiences while falling asleep, sleeping or waking. In a representative UK sample of 4,972 adults, 4.2% reported confusional arousals, 2.2% night terrors and 2.0% sleepwalking, with rates falling with age, and the authors write that arousal parasomnias, especially night terrors and confusional arousals, are often an expression of a mental disorder. The figures are self-reported and probably underestimated.
Ohayon MM, Guilleminault C, Priest RG. Night terrors, sleepwalking, and confusional arousals in the general population: their frequency and relationship to other sleep and mental disorders. J Clin Psychiatry 1999. PMID 10221293
REM sleep behavior disorder, in which people act out their dreams, has been measured with polysomnography in the general population. Of 1,997 participants in a Swiss population study (mean age 59), 21 fulfilled the criteria, which gives an estimated prevalence of 1.06% (95% CI 0.61 to 1.50), with no difference between men and women.
Haba-Rubio J, Frauscher B, Marques-Vidal P, et al. Prevalence and determinants of rapid eye movement sleep behavior disorder in the general population. Sleep 2018. PMID 29216391
The parasomnia pages are Why do people sleepwalk?, Night terrors in adults, Waking up confused, REM sleep behavior disorder, Nightmares every night, Sleep paralysis, Is sleep talking normal?, What causes sleep talking, Sexsomnia, Groaning in your sleep and Exploding head syndrome.
Sleep-related movement disorders
This group includes restless legs syndrome, an urge to move the legs that is worse in the evening and at rest, and grinding of the teeth in sleep. A synthesis of nearly 50 community studies reports that restless legs prevalence in adults ranges from 9.4 to 15% as a symptom only, 3.9 to 14.3% when minimal diagnostic criteria are met, 2.2 to 7.9% when frequency and severity are added, and 1.9 to 4.6% when mimics are excluded. It is higher in women than in men.
Ohayon MM, O'Hara R, Vitiello MV. Epidemiology of restless legs syndrome: a synthesis of the literature. Sleep Med Rev 2012. PMID 21795081
See Restless legs syndrome, Teeth grinding in your sleep, Jaw pain and Hypnic jerks, the sudden twitches at sleep onset.
When to see a doctor, and what a recording adds
Other sleep conditions, the seventh group, are the leftovers that do not fit elsewhere. Whichever of the types of sleep disorders you suspect, get help when a symptom lasts more than a few weeks, you are sleepy while driving or at work, a partner has seen you stop breathing, you hurt yourself or someone else in your sleep, or low mood comes with the sleep problem.
A sleep app cannot tell you which of these groups you belong to. It can describe your nights, and the doctor decides what they mean.
SleepTrace listens through the phone's microphone and estimates sleep phases from the sound alone. It labels snoring, talking and coughing with short clips (3 playable a month on the free plan), marks apparent breathing pauses with a timestamp, and shows a sleep apnea indicator as a screening estimate, not a diagnosis. Against the groups above, that gives a record that can inform the breathing group and the sound side of parasomnias, plus a log of how often you woke. It cannot see movement, position, teeth grinding, mouth breathing, reflux or restless legs, and it cannot measure your body clock or diagnose insomnia. It works on iPhone and Android; the app has to stay open during the night and the phone has to be charging.
Frequently asked questions
The International Classification of Sleep Disorders, third edition, identifies seven major categories: insomnia disorders, sleep-related breathing disorders, central disorders of hypersomnolence, circadian rhythm sleep-wake disorders, sleep-related movement disorders, parasomnias and other sleep disorders.
Insomnia. A review of more than 50 community surveys found that about one third of a general population presents at least one insomnia symptom, 9 to 15% when daytime consequences are required, and about 6% meet a diagnosis.
A literature-based analysis estimated that 936 million adults aged 30 to 69 have mild to severe obstructive sleep apnea worldwide, and 425 million have moderate to severe. The estimate used an apnea-hypopnea index of 5 or more events per hour for mild to severe, and the study was funded by ResMed, a manufacturer of treatment devices.
Both. Insomnia disorder is a diagnosis in its own right, defined by dissatisfaction with sleep and difficulty falling or staying asleep with daytime impairment, but it also often occurs alongside other conditions such as pain and depression, and an insomnia symptom can be the first sign of another sleep disorder.
You cannot reliably tell from symptoms alone. A doctor starts with a sleep history, a sleep diary and questions about health and medicines, and may add tests such as polysomnography when a breathing or movement disorder is suspected. A written log of the nights, a partner's observations and a recording can help that conversation.
SleepTrace is a wellness app, not a medical device. This article is general information, not medical advice. If your symptoms are frequent, severe or worrying, please talk to a doctor.
A list of disorders cannot tell you which one, if any, is yours, and only a doctor can. SleepTrace gives you something to bring: how fragmented the nights are, whether you snore and when, and clips of snoring, coughing and talking. It cannot see leg symptoms or the body clock, and the breathing pause indicator is a screening, not a diagnosis.
Hear your own night. SleepTrace turns a night of audio into your sleep phases, the sounds you made, and how it all trends. Works without a wearable, better with one. Your phone on the nightstand is enough to start. Get it for iPhone or Android →