A sleep disorder, or somnipathy, is a

medical disorder A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism, and that is not immediately due to any external injury. Diseases are often known to be medical conditions that ar ...

of an individual's

sleep Sleep is a sedentary state of mind and body. It is characterized by altered consciousness, relatively inhibited sensory activity, reduced muscle activity and reduced interactions with surroundings. It is distinguished from wakefulness by a de ...

patterns. Some sleep disorders are severe enough to interfere with normal physical, mental, social and emotional functioning.

Polysomnography Polysomnography (PSG), a type of sleep study, is a multi-parameter study of sleep and a diagnostic tool in sleep medicine. The test result is called a polysomnogram, also abbreviated PSG. The name is derived from Greek and Latin roots: the Gree ...

and actigraphy are tests commonly ordered for diagnosing sleep disorders. Sleep disorders are broadly classified into

dyssomnia Dyssomnias are a broad classification of sleeping disorders involving difficulty getting to sleep, remaining asleep, or of excessive sleepiness. Dyssomnias are primary disorders of initiating or maintaining sleep or of excessive sleepiness and ar ...

parasomnia Parasomnias are a category of sleep disorders that involve abnormal movements, behaviors, emotions, perceptions, and dreams that occur while falling asleep, sleeping, between sleep stages, or during arousal from sleep. Parasomnias are dissociate ...

circadian rhythm sleep disorder Circadian rhythm sleep disorders (CRSD), also known as circadian rhythm sleep-wake disorders (CRSWD), are a family of sleep disorders which affect the timing of sleep. CRSDs arise from a persistent pattern of sleep/wake disturbances that can be ...

s involving the timing of sleep, and other disorders including ones caused by medical or psychological conditions. When a person struggles to fall asleep and/or stay asleep with no obvious cause, it is referred to as

insomnia Insomnia, also known as sleeplessness, is a sleep disorder in which people have trouble sleeping. They may have difficulty falling asleep, or staying asleep as long as desired. Insomnia is typically followed by daytime sleepiness, low energy, ...

, the most common sleep disorder. Others include

sleep apnea Sleep apnea, also spelled sleep apnoea, is a sleep disorder in which pauses in breathing or periods of shallow breathing during sleep occur more often than normal. Each pause can last for a few seconds to a few minutes and they happen many times ...

narcolepsy Narcolepsy is a long-term neurological disorder that involves a decreased ability to regulate sleep–wake cycles. Symptoms often include periods of excessive daytime sleepiness and brief involuntary sleep episodes. About 70% of those affec ...

and

hypersomnia Hypersomnia is a neurological disorder of excessive time spent sleeping or excessive sleepiness. It can have many possible causes (such as seasonal affective disorder) and can cause distress and problems with functioning. In the fifth edition ...

(excessive sleepiness at inappropriate times),

sleeping sickness African trypanosomiasis, also known as African sleeping sickness or simply sleeping sickness, is an insect-borne parasitic infection of humans and other animals. It is caused by the species ''Trypanosoma brucei''. Humans are infected by two typ ...

(disruption of sleep cycle due to infection),

sleepwalking Sleepwalking, also known as somnambulism or noctambulism, is a phenomenon of combined sleep and wakefulness. It is classified as a sleep disorder belonging to the parasomnia family. It occurs during slow wave stage of sleep, in a state of low ...

, and

night terror Night terror, also called sleep terror, is a sleep disorder causing feelings of panic or dread and typically occurring during the first hours of stage 3–4 non-rapid eye movement (NREM) sleep and lasting for 1 to 10 minutes. It can last long ...

s. Sleep disruptions can be caused by various issues, including teeth grinding (

bruxism Bruxism is excessive teeth grinding or jaw clenching. It is an oral parafunctional activity; i.e., it is unrelated to normal function such as eating or talking. Bruxism is a common behavior; reports of prevalence range from 8% to 31% in the gene ...

) and

s. Management of sleep disturbances that are secondary to mental, medical or substance abuse disorders should focus on the underlying conditions. Primary sleep disorders are common in both children and adults. However, there is a significant lack of awareness in children with sleep disorders, due to most cases being unidentified. Several common factors involved in the onset of a sleep disorder include increased medication use, age-related changes in circadian rhythms, environmental changes, lifestyle changes,Roepke, S. K., & Ancoli-Israel, S. (2010). Sleep disorders in the elderly. The Indian Journal of Medical Research, 131, 302–310. pre-diagnosed physiological problems, or stress. Among the elderly, the risk of developing sleep disordered breathing, periodic limb movements, restless legs syndrome, REM sleep behavior disorders, insomnia, and circadian rhythm disturbances is especially increased.

List of conditions

There are a number of sleep disorders. The following list includes some of them: *

Bruxism Bruxism is excessive teeth grinding or jaw clenching. It is an oral parafunctional activity; i.e., it is unrelated to normal function such as eating or talking. Bruxism is a common behavior; reports of prevalence range from 8% to 31% in the gene ...

, involuntary grinding or clenching of the teeth while sleeping *

Catathrenia Catathrenia or nocturnal groaning is a sleep-related breathing disorder, consisting of end-inspiratory apnea (breath holding) and expiratory groaning during sleep. The name originates from the Greek ''kata'' (below) and ''threnia'' (to lament), ...

, nocturnal groaning during prolonged exhalation *

Delayed sleep phase disorder Delayed sleep phase disorder (DSPD), more often known as delayed sleep phase syndrome and also as delayed sleep–wake phase disorder, is a delaying of a person's circadian rhythm (biological clock) compared to those of societal norms. The diso ...

(DSPD), inability to awaken and fall asleep at socially acceptable times but no problem with sleep maintenance, a disorder of

circadian rhythm A circadian rhythm (), or circadian cycle, is a natural, internal process that regulates the sleep–wake cycle and repeats roughly every 24 hours. It can refer to any process that originates within an organism (i.e., Endogeny (biology), endogeno ...

s. Other such disorders are

advanced sleep phase disorder Advanced Sleep Phase Disorder (ASPD), also known as the advanced sleep-phase type (ASPT) of circadian rhythm sleep disorder, is a condition that is characterized by a recurrent pattern of early evening (e.g. 7-9 PM) sleepiness and very early mor ...

(ASPD),

non-24-hour sleep–wake disorder Non-24-hour sleep–wake disorder (non-24 or N24SWD) is one of several chronic circadian rhythm sleep disorders (CRSDs). It is defined as a "chronic steady pattern comprising ..daily delays in sleep onset and wake times in an individual livin ...

(non-24) in the sighted or in the blind, and

irregular sleep wake rhythm Irregular, irregulars or irregularity may refer to any of the following: Astronomy * Irregular galaxy * Irregular moon * Irregular variable, a kind of star Language * Irregular inflection, the formation of derived forms such as plurals in ...

, all much less common than DSPD, as well as the situational

shift work sleep disorder Shift work sleep disorder (SWSD) is a circadian rhythm sleep disorder characterized by insomnia, excessive sleepiness, or both affecting people whose work hours overlap with the typical sleep period. Insomnia can be the difficulty to fall asleep ...

. *

Fatal familial insomnia Fatal insomnia is an extremely rare genetic (and even more rarely, sporadic) disorder that results in trouble sleeping as its hallmark symptom. The problems with sleeping typically start out gradually and worsen over time. Eventually, the patien ...

, an extremely rare prion disease that causes a complete cessation of sleep, leading quickly to death by sleep deprivation. * Hypopnea syndrome, abnormally shallow breathing or slow respiratory rate while sleeping *

Idiopathic hypersomnia Idiopathic hypersomnia (IH) is a neurological disorder which is characterized primarily by excessive sleep and excessive daytime sleepiness (EDS). The condition typically becomes evident in early adulthood and most patients diagnosed with IH will ...

, a primary, neurologic cause of long-sleeping, sharing many similarities with narcolepsy *

Insomnia Insomnia, also known as sleeplessness, is a sleep disorder in which people have trouble sleeping. They may have difficulty falling asleep, or staying asleep as long as desired. Insomnia is typically followed by daytime sleepiness, low energy, ...

disorder (primary insomnia), chronic difficulty in falling asleep and/or maintaining sleep when no other cause is found for these symptoms. Insomnia can also be comorbid with or secondary to other disorders. *

Kleine–Levin syndrome Kleine–Levin syndrome (KLS) is a rare disorder characterized by persistent episodic hypersomnia and cognitive or mood changes. Many patients also experience hyperphagia, hypersexuality and other symptoms. Patients generally experience recurrent e ...

, a rare disorder characterized by persistent episodic hypersomnia and cognitive or mood changes *

Narcolepsy Narcolepsy is a long-term neurological disorder that involves a decreased ability to regulate sleep–wake cycles. Symptoms often include periods of excessive daytime sleepiness and brief involuntary sleep episodes. About 70% of those affec ...

, characterized by

excessive daytime sleepiness Excessive daytime sleepiness (EDS) is characterized by persistent sleepiness and often a general lack of energy, even during the day after apparently adequate or even prolonged nighttime sleep. EDS can be considered as a broad condition encompass ...

(EDS) and so-called "sleep attacks," relatively sudden-onset, irresistible urges to sleep, which may interfere with occupational and social commitments. About 70% of those who have narcolepsy also have

cataplexy Cataplexy is a sudden and transient episode of muscle weakness accompanied by full conscious awareness, typically triggered by emotions such as laughing, crying, or terror. Cataplexy affects approximately 70% of people who have narcolepsy, and is ...

, a sudden weakness in the motor muscles that can result in collapse to the floor while retaining full conscious awareness. *

Night terror Night terror, also called sleep terror, is a sleep disorder causing feelings of panic or dread and typically occurring during the first hours of stage 3–4 non-rapid eye movement (NREM) sleep and lasting for 1 to 10 minutes. It can last long ...

, ''Pavor nocturnus'', sleep terror disorder, an abrupt awakening from sleep with behavior consistent with terror *

Nocturia Nocturia is defined by the International Continence Society (ICS) as “the complaint that the individual has to wake at night one or more times for voiding (''i.e. to urinate'').” The term is derived from Latin ''nox, night'', and Greek '' �αο ...

, a frequent need to get up and urinate at night. It differs from

enuresis Enuresis is a repeated inability to control urination. Use of the term is usually limited to describing people old enough to be expected to exercise such control. Involuntary urination is also known as urinary incontinence. The term "enuresis" co ...

, or bed-wetting, in which the person does not arouse from sleep, but the bladder nevertheless empties. *

Parasomnia Parasomnias are a category of sleep disorders that involve abnormal movements, behaviors, emotions, perceptions, and dreams that occur while falling asleep, sleeping, between sleep stages, or during arousal from sleep. Parasomnias are dissociate ...

s, disruptive sleep-related events involving inappropriate actions during sleep, for example sleepwalking, night-terrors and catathrenia. *

Periodic limb movements in sleep Periodic limb movement disorder (PLMD) is a sleep disorder where the patient moves limbs involuntarily and periodically during sleep, and has symptoms or problems related to the movement. PLMD should not be confused with restless legs syndrome (RL ...

(PLMS), sudden involuntary movement of the arms and/or legs during sleep. In the absence of other sleep disorders, PLMS may cause sleep disruption and impair sleep quality, leading to

periodic limb movement disorder Periodic limb movement disorder (PLMD) is a sleep disorder where the patient moves limbs involuntarily and periodically during sleep, and has symptoms or problems related to the movement. PLMD should not be confused with restless legs syndrome (RL ...

(PLMD). * Other limb movements in sleep, including hypneic jerks and

nocturnal myoclonus Periodic limb movement disorder (PLMD) is a sleep disorder where the patient moves limbs involuntarily and periodically during sleep, and has symptoms or problems related to the movement. PLMD should not be confused with restless legs syndrome (RL ...

. *

Rapid eye movement sleep behavior disorder Rapid eye movement sleep behavior disorder or REM behavior disorder (RBD) is a sleep disorder in which people act out their dreams. It involves abnormal behavior during the sleep phase with rapid eye movement (REM) sleep. The major feature of ...

(RBD), acting out violent or dramatic dreams while in REM sleep, sometimes injuring bed partner or self (REM sleep disorder or RSD) *

Restless legs syndrome Restless legs syndrome (RLS), also known as Willis-Ekbom disease (WED), is generally a long-term disorder that causes a strong urge to move one's legs. There is often an unpleasant feeling in the legs that improves somewhat by moving them. This ...

(RLS), an irresistible urge to move legs. *

Shift work sleep disorder Shift work sleep disorder (SWSD) is a circadian rhythm sleep disorder characterized by insomnia, excessive sleepiness, or both affecting people whose work hours overlap with the typical sleep period. Insomnia can be the difficulty to fall asleep ...

(SWSD), a situational

. (

Jet lag Jet lag is a physiological condition that results from alterations to the body's circadian rhythms caused by rapid long-distance trans-meridian (east–west or west–east) travel. For example, someone flying from New York to London, i.e. fr ...

was previously included as a situational circadian rhythm sleep disorder, but it does not appear in

DSM-5 The ''Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition'' (DSM-5), is the 2013 update to the ''Diagnostic and Statistical Manual of Mental Disorders'', the taxonomic and diagnostic tool published by the American Psychiatric ...

, see

Diagnostic and Statistical Manual of Mental Disorders The ''Diagnostic and Statistical Manual of Mental Disorders'' (DSM; latest edition: DSM-5-TR, published in March 2022) is a publication by the American Psychiatric Association (APA) for the classification of mental disorders using a common langua ...

for more). *

Sleep apnea Sleep apnea, also spelled sleep apnoea, is a sleep disorder in which pauses in breathing or periods of shallow breathing during sleep occur more often than normal. Each pause can last for a few seconds to a few minutes and they happen many times ...

obstructive sleep apnea Obstructive sleep apnea (OSA) is the most common sleep-related breathing disorder and is characterized by recurrent episodes of complete or partial obstruction of the upper airway leading to reduced or absent breathing during sleep. These episod ...

, obstruction of the airway during sleep, causing lack of sufficient deep sleep, often accompanied by snoring. Other forms of sleep apnea are less common. Obstructive sleep apnea (OSA) is a medical disorder that is caused by repetitive collapse of the upper airway (back of the throat) during sleep. For the purposes of sleep studies, episodes of full upper airway collapse for at least ten seconds are called apneas. *

Sleep paralysis Sleep paralysis is a state, during waking up or falling asleep, in which one is conscious but is completely paralyzed. During an episode, one may hallucinate (hear, feel, or see things that are not there), which often results in fear. Episodes ...

, characterized by temporary

paralysis Paralysis (also known as plegia) is a loss of motor function in one or more muscles. Paralysis can also be accompanied by a loss of feeling (sensory loss) in the affected area if there is sensory damage. In the United States, roughly 1 in 50 ...

of the body shortly before or after sleep. Sleep paralysis may be accompanied by

visual The visual system comprises the sensory organ (the eye) and parts of the central nervous system (the retina containing photoreceptor cells, the optic nerve, the optic tract and the visual cortex) which gives organisms the sense of sight (the ...

, auditory or

tactile Tactile may refer to: * Tactile, related to the sense of touch * Haptics (disambiguation) * Tactile (device), a text-to-braille translation device See also * Tangibility, in law * Somatosensory system, where sensations are processed * CD96 CD ...

hallucination A hallucination is a perception in the absence of an external stimulus that has the qualities of a real perception. Hallucinations are vivid, substantial, and are perceived to be located in external objective space. Hallucination is a combinatio ...

s. It is not a disorder unless severe, and is often seen as part of narcolepsy. *

Sleepwalking Sleepwalking, also known as somnambulism or noctambulism, is a phenomenon of combined sleep and wakefulness. It is classified as a sleep disorder belonging to the parasomnia family. It occurs during slow wave stage of sleep, in a state of low ...

or ''somnambulism'', engaging in activities normally associated with wakefulness (such as

eating Eating (also known as consuming) is the ingestion of food, typically to provide a heterotrophic organism with energy and to allow for growth. Animals and other heterotrophs must eat in order to survive — carnivores eat other animals, herbi ...

or dressing), which may include walking, without the conscious knowledge of the subject. * Somniphobia, one cause of sleep deprivation, a dread/ fear of falling asleep or going to bed. Signs of the illness include anxiety and panic attacks before and during attempts to sleep.

Types

Dyssomnia Dyssomnias are a broad classification of sleeping disorders involving difficulty getting to sleep, remaining asleep, or of excessive sleepiness. Dyssomnias are primary disorders of initiating or maintaining sleep or of excessive sleepiness and ar ...

s – A broad category of sleep disorders characterized by either

. The three major subcategories include intrinsic (i.e., arising from within the body), extrinsic (secondary to environmental conditions or various pathologic conditions), and disturbances of circadian rhythm. **

: Insomnia may be primary or it may be comorbid with or secondary to another disorder such as a mood disorder (i.e., emotional stress, anxiety, depression) or underlying health condition (i.e., asthma, diabetes, heart disease, pregnancy or neurological conditions). ** Primary

: Hypersomnia of central or brain origin ***

: A chronic neurological disorder (or dyssomnia), which is caused by the brain's inability to control sleep and wakefulness. ***

: A chronic neurological disease similar to narcolepsy, in which there is an increased amount of fatigue and sleep during the day. Patients who have idiopathic hypersomnia cannot obtain a healthy amount of sleep for a regular day of activities. This hinders the patients' ability to perform well, and patients have to deal with this for the rest of their lives. *** Recurrent hypersomnia, including

*** Post traumatic hypersomnia *** Menstrual-related hypersomnia ** Sleep disordered breathing (SDB), including (non-exhaustive): *** Several types of

***

Snoring Snoring is the vibration of respiratory structures and the resulting sound due to obstructed air movement during breathing while sleeping. The sound may be soft or loud and unpleasant. Snoring during sleep may be a sign, or first alarm, of obs ...

*** Upper airway resistance syndrome **

Restless leg syndrome Restless legs syndrome (RLS), also known as Willis-Ekbom disease (WED), is generally a long-term disorder that causes a strong urge to move one's legs. There is often an unpleasant feeling in the legs that improves somewhat by moving them. This ...

Periodic limb movement disorder Periodic limb movement disorder (PLMD) is a sleep disorder where the patient moves limbs involuntarily and periodically during sleep, and has symptoms or problems related to the movement. PLMD should not be confused with restless legs syndrome (RL ...

Circadian rhythm sleep disorders Circadian rhythm sleep disorders (CRSD), also known as circadian rhythm sleep-wake disorders (CRSWD), are a family of sleep disorders which affect the timing of sleep. CRSDs arise from a persistent pattern of sleep/wake disturbances that can be ...

Advanced sleep phase disorder Advanced Sleep Phase Disorder (ASPD), also known as the advanced sleep-phase type (ASPT) of circadian rhythm sleep disorder, is a condition that is characterized by a recurrent pattern of early evening (e.g. 7-9 PM) sleepiness and very early mor ...

Non-24-hour sleep–wake disorder Non-24-hour sleep–wake disorder (non-24 or N24SWD) is one of several chronic circadian rhythm sleep disorders (CRSDs). It is defined as a "chronic steady pattern comprising ..daily delays in sleep onset and wake times in an individual livin ...

s – A category of sleep disorders that involve abnormal and unnatural movements, behaviors, emotions, perceptions, and dreams in connection with sleep. ** Bedwetting or sleep enuresis **

(Tooth-grinding) **

– nocturnal groaning **

Exploding head syndrome Exploding head syndrome (EHS) is an abnormal sensory perception during sleep in which a person experiences auditory hallucinations that are loud and of short duration when falling asleep or waking up. The noise may be frightening, typically occ ...

– Waking up in the night hearing loud noises. **

Sleep terror Night terror, also called sleep terror, is a sleep disorder A sleep disorder, or somnipathy, is a medical disorder of an individual's sleep patterns. Some sleep disorders are severe enough to interfere with normal physical, mental, social a ...

(or Pavor nocturnus) – Characterized by a sudden arousal from deep sleep with a scream or cry, accompanied by some behavioral manifestations of intense fear. **

REM sleep behavior disorder Rapid eye movement sleep behavior disorder or REM behavior disorder (RBD) is a sleep disorder in which people act out their dreams. It involves abnormal behavior during the sleep phase with rapid eye movement (REM) sleep. The major feature of ...

(or somnambulism) **

Sleep talking Somniloquy, commonly referred to as sleep-talking, is a parasomnia in which one speaks aloud while asleep. It can range from simple mumbling sounds to loud shouts or long, frequently inarticulate, speeches. It can occur many times during a sleep c ...

(or somniloquy) **

Sleep sex Sexsomnia, also known as sleep sex, is a distinct form of parasomnia, or an abnormal activity that occurs while an individual is asleep. Sexsomnia is characterized by an individual engaging in sexual acts while in non-rapid eye movement ( NREM) ...

(or sexsomnia) * Medical or psychiatric conditions that may produce sleep disorders **

22q11.2 deletion syndrome DiGeorge syndrome, also known as 22q11.2 deletion syndrome, is a syndrome caused by a microdeletion on the long arm of chromosome 22. While the symptoms can vary, they often include congenital heart problems, specific facial features, frequent i ...

Alcoholism Alcoholism is, broadly, any drinking of alcohol (drug), alcohol that results in significant Mental health, mental or physical health problems. Because there is disagreement on the definition of the word ''alcoholism'', it is not a recognize ...

Mood disorders A mood disorder, also known as an affective disorder, is any of a group of conditions of mental and behavioral disorder where a disturbance in the person's mood is the main underlying feature. The classification is in the ''Diagnostic and Stat ...

*** Depression **

Anxiety disorder Anxiety disorders are a cluster of mental disorders characterized by significant and uncontrollable feelings of anxiety and fear such that a person's social, occupational, and personal function are significantly impaired. Anxiety may cause physi ...

Nightmare disorder Nightmare disorder, also known as dream anxiety disorder, is a sleep disorder characterized by frequent nightmares. The nightmares, which often portray the individual in a situation that jeopardizes their life or personal safety, usually occur du ...

Panic Panic is a sudden sensation of fear, which is so strong as to dominate or prevent reason and logical thinking, replacing it with overwhelming feelings of anxiety and frantic agitation consistent with an animalistic fight-or-flight reactio ...

Psychosis Psychosis is a condition of the mind that results in difficulties determining what is real and what is not real. Symptoms may include delusions and hallucinations, among other features. Additional symptoms are incoherent speech and behavior ...

(such as

Schizophrenia Schizophrenia is a mental disorder characterized by continuous or relapsing episodes of psychosis. Major symptoms include hallucinations (typically hearing voices), delusions, and disorganized thinking. Other symptoms include social withdra ...

) *

Sleeping sickness African trypanosomiasis, also known as African sleeping sickness or simply sleeping sickness, is an insect-borne parasitic infection of humans and other animals. It is caused by the species ''Trypanosoma brucei''. Humans are infected by two typ ...

– a parasitic disease which can be transmitted by the

Tsetse fly Tsetse ( , or ) (sometimes spelled tzetze; also known as tik-tik flies), are large, biting flies that inhabit much of tropical Africa. Tsetse flies include all the species in the genus ''Glossina'', which are placed in their own family, Glo ...

Causes

A systematic review found that traumatic childhood experiences (such as family conflict or sexual trauma) significantly increases the risk for a number of sleep disorders in adulthood, including

, and

. In addition, an evidence-based synopsis suggests that idiopathic REM sleep behavior disorder (iRBD) may have a hereditary component. A total of 632 participants, half with iRBD and half without, completed self-report questionnaires. The results of the study suggest that people with iRBD are more likely to report having a first-degree relative with the same sleep disorder than people of the same age and sex that do not have the disorder. More research needs to be conducted to further understand the hereditary nature of sleep disorders. A population susceptible to the development of sleep disorders includes people who have experienced a traumatic brain injury (TBI). Because many researchers have focused on this issue, a systematic review was conducted to synthesize their findings. The results indicate that individuals who experienced a TBI are most disproportionately at risk for developing narcolepsy, obstructive sleep apnea, excessive daytime sleepiness, and insomnia. The study's complete findings can be found in the table below:

Sleep disorders and Neurodegenerative Diseases

Neurodegenerative diseases have often been associated with sleep disorders, mainly when they are characterized by abnormal accumulation of

alpha-synuclein Alpha-synuclein is a protein that, in humans, is encoded by the ''SNCA'' gene. Alpha-synuclein is a neuronal protein that regulates synaptic vesicle trafficking and subsequent neurotransmitter release. It is abundant in the brain, while smaller a ...

, such as

multiple system atrophy Multiple system atrophy (MSA) is a rare neurodegenerative disorder characterized by autonomic dysfunction, tremors, slow movement, muscle rigidity, and postural instability (collectively known as parkinsonism) and ataxia. This is caused by progr ...

(MSA),

Parkinson's disease Parkinson's disease (PD), or simply Parkinson's, is a long-term degenerative disorder of the central nervous system that mainly affects the motor system. The symptoms usually emerge slowly, and as the disease worsens, non-motor symptoms becom ...

(PD) and

Lewy body disease Lewy body dementias are two similar and common subtypes of dementia—dementia with Lewy bodies (DLB) and Parkinson's disease dementia (PDD). Both are characterized by changes in thinking, movement, behavior, and mood. The two conditions have sim ...

(LBD).Aurora, R., Zak, R., Maganti, R., Auerbach, S., Casey, K., Chowdhuri, S., . . . Morgenthaler, T. (2010). Best practice guide for the treatment of REM sleep behavior disorder (RBD). Journal of Clinical Sleep Medicine : JCSM : Official Publication of the American Academy of Sleep Medicine, 6(1), 85-95.Zhong, Naismith, Rogers, & Lewis. (2011). Sleep–wake disturbances in common neurodegenerative diseases: A closer look at selected aspects of the neural circuitry. Journal of the Neurological Sciences, 307(1-2), 9-14.Bjørnarå, Dietrichs, & Toft. (2013). REM sleep behavior disorder in Parkinson's disease – Is there a gender difference? Parkinsonism and Related Disorders, 19(1), 120-122.Malkani, R., & Attarian, H. (2015). Sleep in Neurodegenerative Disorders. Current Sleep Medicine Reports, 1(2), 81-90.Bjørnarå, K., Dietrichs, E., & Toft, M. (2015). Longitudinal assessment of probable rapid eye movement sleep behavior disorder in Parkinson's disease. European Journal of Neurology, 22(8), 1242-1244.Wang, P., Wing, Y.K., Xing, J. et al. Aging Clin Exp Res (2016) 28: 951. https://doi.org/10.1007/s40520-015-0382-8McCarter, S., & Howell, J. (2017). REM Sleep Behavior Disorder and Other Sleep Disturbances in Non-Alzheimer Dementias. Current Sleep Medicine Reports, 3(3), 193-203. For instance, people diagnosed with PD have often presented different kinds of sleep concerns, commonly in regard to

(around 70% of the PD population),

(more than 50% of the PD population), and

(RBD) - that may affect around 40% of the PD population and it is associated with increased motor symptoms. Furthermore, RBD has been highlighted as a strong precursor for future development of those neurodegenerative diseases over several years in prior, which seems to be a great opportunity for improving the treatments of the disease. Sleep disturbances have been also observed in

Alzheimer's disease Alzheimer's disease (AD) is a neurodegeneration, neurodegenerative disease that usually starts slowly and progressively worsens. It is the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in short-term me ...

(AD), affecting about 45% of its population. When based on caregiver reports, this percentage increases to about 70%.Dick-Muehlke, C. (2015). Psychosocial studies of the individual's changing perspectives in Alzheimer's disease (Premier Reference Source). Hershey, PA: Medical Information Science Reference. As well as in PD population, insomnia and

are frequently recognized in AD patients, which have been associated with accumulation of

beta-amyloid Amyloid beta (Aβ or Abeta) denotes peptides of 36–43 amino acids that are the main component of the amyloid plaques found in the brains of people with Alzheimer's disease. The peptides derive from the amyloid precursor protein (APP), which i ...

s (CRSD) and

melatonin Melatonin is a natural product found in plants and animals. It is primarily known in animals as a hormone released by the pineal gland in the brain at night, and has long been associated with control of the sleep–wake cycle. In vertebrates ...

alteration. Additionally, changes in

sleep architecture Sleep is a sedentary state of mind and body. It is characterized by altered consciousness, relatively inhibited sensory activity, reduced muscle activity and reduced interactions with surroundings. It is distinguished from wakefulness by a d ...

are observed in AD. Although sleep architecture seems to naturally change with age, its development appears aggravated in AD patients. SWS potentially decreases (and is sometimes absent), spindles and the length of time spent in REM sleep are also reduced, while its latency increases. Poor sleep onset in AD has been associated with dream-related hallucination, increased restlessness, wandering and agitation that seem related to sundowning - a typical chronobiological phenomenon presented in the disease. The neurodegenerative conditions are commonly related to structural brain impairment, which might disrupt the states of sleep and wakefulness, circadian rhythm, motor or non motor functioning. On the other hand, sleep disturbances are frequently related to worsening patient's cognitive functioning, emotional state and quality of life. Furthermore, these abnormal behavioral symptoms negatively contribute to overwhelming their relatives and caregivers. The limited research related to it and the increasing life expectancy calls for a deeper understanding of the relationship between sleep disorders and neurodegenerative disease.

Sleep disturbances and Alzheimer's Disease

More than 70% of people with dementia are affected by Alzheimer's disease (AD). Despite this high number, our understanding of the underlying mechanisms for disease progression remains very limited. However, recent studies have highlighted a link between sleep disturbances and Alzheimer's disease. Sleep changes with normal aging. Over time, a decrease in time sleeping and a decrease in the quantity of

NREM Non-rapid eye movement sleep (NREM), also known as quiescent sleep, is, collectively, sleep stages 1–3, previously known as stages 1–4. Rapid eye movement sleep (REM) is not included. There are distinct electroencephalographic and other char ...

sleep can be observed, specifically in NREM SWS (less than 10% of the SWS is maintained). Older people also are more prone to insomnia or sleep apnea. In Alzheimer's disease, in addition to cognitive decline and memory impairment, there are also significant sleep disturbances with modified sleep architecture. The latter may consist in sleep fragmentation, reduced sleep duration, insomnia, increased daytime napping, decreased quantity of some sleep stages, and a growing resemblance between some sleep stages (N1 and N2). More than 65% of people with Alzheimer's disease have this type of sleep disturbance. One factor that could explain this change in sleep architecture is a change in circadian rhythm, which regulates sleep. A disruption of the circadian rhythm would generate sleep disturbances. Some studies show that people with AD have a delayed circadian rhythm, whereas in normal aging, an advanced circadian rhythm is present. In addition to these psychological symptoms, at a neurological level there are two main symptoms of Alzheimer's disease. The first is an accumulation of beta-amyloid waste forming aggregate "plaques". The second is an accumulation of tau protein. It has been shown that the sleep-wake cycle acts on the beta-amyloid burden, which is a central component found in AD. As individuals awaken, the production of beta-amyloid protein will be more consistent than its production during sleep. This is explained by two phenomena. The first is that the metabolic activity will be higher during waking, thus resulting in greater secretion of beta-amyloid protein. The second is that oxidative stress will also increase, which leads to greater AB production. On the other hand, it is during sleep that beta-amyloid residues are degraded to prevent plaque formation. The glymphatic system is responsible for this through the phenomenon of glymphatic clearance. Thus, during wakefulness, the AB burden is greater because the metabolic activity and oxidative stress are higher, and there is no protein degradation by the glymphatic clearance. During sleep, the burden is reduced as there is less metabolic activity and oxidative stress (in addition to the glymphatic clearance that occurs). Glymphatic clearance occurs during the NREM SWS sleep. This sleep stage decreases in normal aging, resulting in less glymphatic clearance and increased AB burden that will form AB plaques. Therefore, sleep disturbances in individuals with AD will amplify this phenomenon. The decrease in the quantity and quality of the NREM SWS, as well as the disturbances of sleep will therefore increase the AB plaques. This initially occurs in the hippocampus, which is a brain structure integral in long-term memory formation. Hippocampus cell death occurs, which contributes to diminished memory performance and cognitive decline found in AD. Although the causal relationship is unclear, the development of AD correlates with the development of prominent sleep disorders. In the same way, sleep disorders exacerbate disease progression, forming a positive feedback relationship. As a result, sleep disturbances are no longer only a symptom of AD; the relationship between sleep disturbances and AD is bidirectional. At the same time, it has been shown that memory consolidation in long-term memory (which depends on the hippocampus) occurs during NREM sleep. This indicates that a decrease in the NREM sleep will result in less consolidation, resulting in poorer memory performances in hippocampal-dependent long-term memory. This drop in performance is one of the central symptoms of AD. Recent studies have also linked sleep disturbances, neurogenesis and AD. The subgranular zone and the subventricular zone continued to produce new neurons in adult brains. These new cells are then incorporated into neuronal circuits and the subragranular zone, which is found in the hippocampus. These new cells contribute to learning and memory, playing an essential role in hippocampal-dependent memory. However, recent studies have shown that several factors can interrupt neurogenesis, including stress and prolonged sleep deprivation (more than one day). The sleep disturbances encountered in AD could therefore suppress neurogenesis—and thus impair hippocampal functions. This would contribute to diminished memory performances and the progression of AD, and the progression of AD would aggravate sleep disturbances. Changes in sleep architecture found in patients with AD occur during the preclinical phase of AD. These changes could be used to detect those most at risk of developing AD. However, this is still only theoretical. While the exact mechanisms and the causal relationship between sleep disturbances and AD remains unclear, these findings already provide a better understanding and offer possibilities to improve targeting of at-risk populations—and the implementation of treatments to curb the cognitive decline of AD patients.

Sleep disorder symptoms in psychiatric illnesses

Schizophrenia

In individuals with psychiatric illnesses sleep disorders may include a variety of clinical symptoms, including but not limited to: excessive daytime sleepiness, difficulty falling asleep, difficulty staying asleep, nightmares, sleep talking, sleepwalking, and poor sleep quality. Sleep disturbances - insomnia, hypersomnia and delayed sleep-phase disorder - are quite prevalent in severe mental illnesses such as psychotic disorders. In those with

schizophrenia Schizophrenia is a mental disorder characterized by continuous or relapsing episodes of psychosis. Major symptoms include hallucinations (typically hearing voices), delusions, and disorganized thinking. Other symptoms include social withdra ...

, sleep disorders contribute to cognitive deficits in learning and memory. Sleep disturbances often occur before the onset of psychosis. Sleep deprivation can also produce hallucinations, delusions and depression. A 2019 study investigated the three above-mentioned sleep disturbances in schizophrenia-spectrum (SCZ) and bipolar (BP) disorders in 617 SCZ individuals, 440 BP individuals, and 173 healthy controls (HC). Sleep disturbances were identified using the Inventory for Depressive Symptoms - clinician rated scale (IDS-C). Results suggested that at least one type of sleep disturbance was reported in 78% of the SCZ population, in 69% individuals with BD, and in 39% of healthy controls. The SCZ group reported the most number of sleep disturbances compared to the BD and HC groups; specifically, hypersomnia was more frequent among individuals with SCZ, and delayed sleep phase disorder was three times more common in the SCZ group compared to the BD group. Insomnias were the most frequently reported sleep disturbance across all three groups.

Bipolar disorder

One of the main behavioral symptoms of bipolar disorder is abnormal sleep. Studies have suggested that 23-78% of individuals with bipolar disorders consistently report symptoms of excessive time spent sleeping, or hypersomnia. The pathogenesis of bipolar disorder, including the higher risk of suicidal ideation, could possibly be linked to circadian rhythm variability, and sleep disturbances are a good predictor of mood swings. The most common sleep-related symptom of bipolar disorder is insomnia, in addition to hypersomnia, nightmares, poor sleep quality, OSA, extreme daytime sleepiness, etc. Moreover, animal models have shown that sleep debt can induce episodes of bipolar mania in laboratory mice, but these models are still limited in their potential to explain bipolar disease in humans with all its multifaceted symptoms, including those related to sleep disturbances.

Major depressive disorder (MDD)

Sleep disturbances (insomnia or hypersomnia) are not a necessary diagnostic criterion—but one of the most frequent symptoms of individuals with major depressive disorder (MDD). Among individuals with MDD, insomnia and hypersomnia have prevalence estimates of 88% and 27%, respectively, whereas individuals with insomnia have a threefold increased risk of developing MDD. Depressed mood and sleep efficiency strongly co-vary, and while sleep regulation problems may precede depressive episodes, such depressive episodes may also precipitate sleep deprivation. Fatigue, as well as sleep disturbances such as irregular and excessive sleepiness, are linked to symptoms of depression. Recent research has even pointed to sleep problems and fatigues as potential driving forces bridging MDD symptoms to those of co-occurring generalized anxiety disorder.

Treatment

Treatments for sleep disorders generally can be grouped into four categories: * Behavioral and psychotherapeutic treatment * Rehabilitation and management * Medication * Other somatic treatment None of these general approaches are sufficient for all patients with sleep disorders. Rather, the choice of a specific treatment depends on the patient's diagnosis, medical and psychiatric history, and preferences, as well as the expertise of the treating clinician. Often, behavioral/psychotherapeutic and pharmacological approaches may be compatible, and can effectively be combined to maximize therapeutic benefits. Management of sleep disturbances that are secondary to mental, medical, or substance abuse disorders should focus on the underlying conditions. Medications and somatic treatments may provide the most rapid symptomatic relief from certain disorders, such as narcolepsy, which is best treated with prescription drugs such as

modafinil Modafinil, sold under the brand name Provigil among others, is a central nervous system (CNS) stimulant medication used to treat sleepiness due to narcolepsy, shift work sleep disorder, and obstructive sleep apnea. While it has seen off-label ...

. Others, such as chronic and primary insomnia, may be more amenable to behavioral interventions—with more durable results. Chronic sleep disorders in childhood, which affect some 70% of children with developmental or psychological disorders, are under-reported and under-treated. Sleep-phase disruption is also common among adolescents, whose school schedules are often incompatible with their natural circadian rhythm. Effective treatment begins with careful diagnosis using sleep diaries and perhaps sleep studies. Modifications in

sleep hygiene Sleep hygiene is a behavioral and environmental practice developed in the late 1970s as a method to help people with mild to moderate insomnia. Clinicians assess the sleep hygiene of people with insomnia and other conditions, such as depression, ...

may resolve the problem, but medical treatment is often warranted. Special equipment may be required for treatment of several disorders such as obstructive apnea, circadian rhythm disorders and bruxism. In severe cases, it may be necessary for individuals to accept living with the disorder, however well managed. Some sleep disorders have been found to compromise glucose metabolism.

Allergy treatment

Histamine plays a role in wakefulness in the brain. An allergic reaction over produces histamine, causing wakefulness and inhibiting sleep. Sleep problems are common in people with

allergic rhinitis Allergic rhinitis, of which the seasonal type is called hay fever, is a type of inflammation in the nose that occurs when the immune system overreacts to allergens in the air. Signs and symptoms include a runny or stuffy nose, sneezing, red, i ...

. A study from the N.I.H. found that sleep is dramatically impaired by allergic symptoms, and that the degree of impairment is related to the severity of those symptoms. Treatment of allergies has also been shown to help sleep apnea.

Acupuncture

A review of the evidence in 2012 concluded that current research is not rigorous enough to make recommendations around the use of

acupuncture Acupuncture is a form of alternative medicine and a component of traditional Chinese medicine (TCM) in which thin needles are inserted into the body. Acupuncture is a pseudoscience; the theories and practices of TCM are not based on scientifi ...

for

. The pooled results of two trials on acupuncture showed a moderate likelihood that there may be some improvement to sleep quality for individuals with insomnia. This form of treatment for sleep disorders is generally studied in adults, rather than children. Further research would be needed to study the effects of acupuncture on sleep disorders in children.

Hypnosis

Research suggests that

hypnosis Hypnosis is a human condition involving focused attention (the selective attention/selective inattention hypothesis, SASI), reduced peripheral awareness, and an enhanced capacity to respond to suggestion.In 2015, the American Psychologica ...

may be helpful in alleviating some types and manifestations of sleep disorders in some patients. "Acute and chronic insomnia often respond to relaxation and hypnotherapy approaches, along with sleep hygiene instructions."

Hypnotherapy Hypnotherapy is a type of mind–body intervention in which hypnosis is used to create a state of focused attention and increased suggestibility in the treatment of a medical or psychological disorder or concern. Popularized by 17th and 18th cen ...

has also helped with nightmares and sleep terrors. There are several reports of successful use of hypnotherapy for parasomnias specifically for head and body rocking, bedwetting and sleepwalking. Hypnotherapy has been studied in the treatment of sleep disorders in both adults and children.

Music therapy

Although more research should be done to increase the reliability of this method of treatment, research suggests that

music therapy Music therapy, an allied health profession, "is the clinical and evidence-based use of music interventions to accomplish individualized goals within a therapeutic relationship by a credentialed professional who has completed an approved music th ...

can improve sleep quality in

acute Acute may refer to: Science and technology * Acute angle ** Acute triangle ** Acute, a leaf shape in the glossary of leaf morphology * Acute (medicine), a disease that it is of short duration and of recent onset. ** Acute toxicity, the adverse eff ...

and chronic sleep disorders. In one particular study, participants (18 years or older) who had experienced acute or chronic sleep disorders were put in a randomly controlled trial, and their sleep efficiency, in the form of overall time asleep, was observed. In order to assess sleep quality, researchers used subjective measures (i.e.

questionnaire A questionnaire is a research Research is "creativity, creative and systematic work undertaken to increase the stock of knowledge". It involves the collection, organization and analysis of evidence to increase understanding of a topic, ...

s) and objective measures (i.e.

polysomnography Polysomnography (PSG), a type of sleep study, is a multi-parameter study of sleep and a diagnostic tool in sleep medicine. The test result is called a polysomnogram, also abbreviated PSG. The name is derived from Greek and Latin roots: the Gree ...

). The results of the study suggest that music therapy did improve sleep quality in subjects with acute or chronic sleep disorders, though only when tested subjectively. Although these results are not fully conclusive and more research should be conducted, it still provides evidence that music therapy can be an effective treatment for sleep disorders. In another study specifically looking to help people with insomnia, similar results were seen. The participants that listened to music experienced better sleep quality than those who did not listen to music. Listening to slower pace music before bed can help decrease the heart rate, making it easier to transition into sleep. Studies have indicated that music helps induce a state of relaxation that shifts an individual's internal clock towards the sleep cycle. This is said to have an effect on children and adults with various cases of sleep disorders. Music is most effective before bed once the brain has been conditioned to it, helping to achieve sleep much faster.

Melatonin

Research suggests that

is useful in helping people fall asleep faster (decreased

sleep latency In sleep science, sleep onset latency (SOL) is the length of time that it takes to accomplish the transition from full wakefulness to sleep, normally to the lightest of the non-REM sleep stages. Sleep latency studies Pioneering Stanford Univers ...

), stay asleep longer, and experience improved sleep quality. To test this, a study was conducted that compared subjects who had taken melatonin to subjects with primary sleep disorders who had taken a placebo. Researchers assessed sleep onset latency, total minutes slept, and overall sleep quality in the melatonin and placebo groups to note the differences. In the end, researchers found that melatonin decreased sleep onset latency and increased total sleep time but had an insignificant and inconclusive impact on the quality of sleep compared to the placebo group.

Sleep medicine

Due to rapidly increasing knowledge and understanding of sleep in the 20th century, including the discovery of REM sleep in the 1950s and circadian rhythm disorders in the 70s and 80s, the medical importance of sleep was recognized. By the 1970s in the US, clinics and laboratories devoted to the study of sleep and sleep disorders had been founded, and a need for standards arose. The medical community began paying more attention to primary sleep disorders, such as sleep apnea, as well as the role and quality of sleep in other conditions. Specialists in sleep medicine were originally and continue to be certified by the American Board of Sleep Medicine. Those passing the Sleep Medicine Specialty Exam received the designation "diplomate of the ABSM." Sleep medicine is now a recognized subspecialty within internal medicine,

family medicine Family medicine is a medical specialty within primary care that provides continuing and comprehensive health care for the individual and family across all ages, genders, diseases, and parts of the body. The specialist, who is usually a primary ...

pediatrics Pediatrics ( also spelled ''paediatrics'' or ''pædiatrics'') is the branch of medicine that involves the medical care of infants, children, adolescents, and young adults. In the United Kingdom, paediatrics covers many of their youth until th ...

otolaryngology Otorhinolaryngology ( , abbreviated ORL and also known as otolaryngology, otolaryngology–head and neck surgery (ORL–H&N or OHNS), or ear, nose, and throat (ENT)) is a surgical subspeciality within medicine that deals with the surgical a ...

psychiatry Psychiatry is the medical specialty devoted to the diagnosis, prevention, and treatment of mental disorders. These include various maladaptations related to mood, behaviour, cognition, and perceptions. See glossary of psychiatry. Initial psych ...

and

neurology Neurology (from el, wikt:νεῦρον, νεῦρον (neûron), "string, nerve" and the suffix wikt:-logia, -logia, "study of") is the branch of specialty (medicine), medicine dealing with the diagnosis and treatment of all categories of co ...

in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

. Certification in Sleep medicine shows that the specialist: Competence in sleep medicine requires an understanding of a myriad of very diverse disorders. Many of which present with similar

symptom Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormality showin ...

s such as excessive daytime sleepiness, which, in the absence of volitional

sleep deprivation Sleep deprivation, also known as sleep insufficiency or sleeplessness, is the condition of not having adequate duration and/or quality of sleep to support decent alertness, performance, and health. It can be either chronic or acute and may vary ...

, "is almost inevitably caused by an identifiable and treatable sleep disorder", such as sleep apnea,

idiopathic hypersomnia Idiopathic hypersomnia (IH) is a neurological disorder which is characterized primarily by excessive sleep and excessive daytime sleepiness (EDS). The condition typically becomes evident in early adulthood and most patients diagnosed with IH will ...

, menstrual-related hypersomnia,

idiopathic An idiopathic disease is any disease with an unknown cause or mechanism of apparent wikt:spontaneous, spontaneous origin. From Ancient Greek, Greek ἴδιος ''idios'' "one's own" and πάθος ''pathos'' "suffering", ''idiopathy'' means approxi ...

recurrent stupor, or circadian rhythm disturbances. Another common complaint is insomnia, a set of symptoms which can have a great many different causes, physical and mental. Management in the varying situations differs greatly and cannot be undertaken without a correct diagnosis. Sleep dentistry (

snoring Snoring is the vibration of respiratory structures and the resulting sound due to obstructed air movement during breathing while sleeping. The sound may be soft or loud and unpleasant. Snoring during sleep may be a sign, or first alarm, of obs ...

and

), while not recognized as one of the nine dental specialties, qualifies for board-certification by the American Board of Dental Sleep Medicine (ABDSM). The qualified dentists collaborate with sleep physicians at accredited sleep centers, and can provide oral appliance therapy and upper airway surgery to treat or manage sleep-related breathing disorders. The resulting diplomate status is recognized by the

American Academy of Sleep Medicine The American Academy of Sleep Medicine (AASM) is a United States professional society for the medical subspecialty of sleep medicine which includes disorders of circadian rhythms. It was established in 1975. The organization's functions include t ...

(AASM), and these dentists are organized in the Academy of Dental Sleep Medicine (USA).

Occupational therapy Occupational therapy (OT) is a global healthcare profession. It involves the use of assessment and intervention to develop, recover, or maintain the meaningful activities, or ''occupations'', of individuals, groups, or communities. The field of ...

is an area of medicine that can also address a diagnosis of sleep disorder, as rest and sleep is listed in the Occupational Therapy Practice Framework (OTPF) as its own occupation of daily living. Rest and sleep are described as restorative in order to support engagement in other occupational therapy occupations. In the OTPF, the occupation of rest and sleep is broken down into rest, sleep preparation, and sleep participation. Occupational therapists have been shown to help improve restorative sleep through the use of assistive devices/equipment,

cognitive behavioral therapy for Insomnia Cognitive behavioral therapy for insomnia (CBT-I) is a technique for treating insomnia without (or alongside) medications. Insomnia is a common problem involving trouble falling asleep, staying asleep, or getting quality sleep. CBT-I aims to impro ...

, therapeutic activities, and/or lifestyle interventions. In the UK, knowledge of sleep medicine and possibilities for diagnosis and treatment seem to lag. The Imperial College Healthcare shows attention to obstructive sleep apnea syndrome (OSA) and very few other sleep disorders. Some NHS trusts have specialist clinics for respiratory and/or neurological sleep medicine.

Epidemiology

Children and young adults

According to one meta-analysis of sleep disorders in children,

confusional arousals Confusional arousals are classified as “partial awakenings in which the state of consciousness remains impaired for several minutes without any accompanying major behavioural disorders or severe autonomic responses”. Complete or partial amnesia ...

and

are the two most common sleep disorders among children. An estimated 17.3% of kids between 3 and 13 years old experience confusional arousals. About 17% of children sleepwalk, with the disorder being more common among boys than girls, the peak ages of sleepwalking are from 8 to 12 years old. A different systematic review offers a high range of prevalence rates of sleep bruxism for children. Parasomnias like sleepwalking and talking typically occur during the first part of an individual's sleep cycle, the first slow wave of sleep During the first slow wave of sleep period of the sleep cycle the mind and body slow down causing one to feel drowsy and relaxed. At this stage it is the easiest to wake up, therefore many children do not remember what happened during this time. Nightmares are also considered a parasomnia among children, who typically remember what took place during the nightmare. However, nightmares only occur during the last stage of sleep - Rapid Eye Movement (REM) sleep. REM is the deepest stage of sleep, it is named for the host of neurological and physiological responses an individual can display during this period of the sleep cycle which are similar to being awake. Between 15.29% and 38.6% of preschoolers grind their teeth at least one night a week. All but one of the included studies reports decreasing bruxist prevalence as age increased, as well as a higher prevalence among boys than girls. Another systematic review noted 7-16% of young adults have

delayed sleep phase disorder Delayed sleep phase disorder (DSPD), more often known as delayed sleep phase syndrome and also as delayed sleep–wake phase disorder, is a delaying of a person's circadian rhythm (biological clock) compared to those of societal norms. The diso ...

. This disorder reaches peak prevalence when people are in their 20s. Between 20 and 26% of adolescents report a

sleep onset latency In sleep science, sleep onset latency (SOL) is the length of time that it takes to accomplish the transition from full wakefulness to sleep, normally to the lightest of the non-REM sleep stages. Sleep latency studies Pioneering Stanford Universi ...

of greater than 30 minutes. Also, 7-36% have difficulty initiating sleep. Asian teens tend to have a higher prevalence of all of these adverse sleep outcomes—than their North American and European counterparts. By adulthood, parasomnias can normally be resolved due to a person's growth; however, 4% of people have recurring symptoms.

Effects of Untreated Sleep Disorders

Children and young adults who do not get enough sleep due to sleep disorders also have many other health problems such as obesity and physical problems where it could interfere with everyday life. It is recommended that children and young adults stick to the hours of sleep recommended by the CDC, as it helps increase mental health, physical health, and more.

Insomnia

is a prevalent form of sleep deprivation. Individuals with insomnia may have problems falling asleep, staying asleep, or a combination of both resulting in hyposomnia - i.e. insufficient quantity and poor quality of sleep. Combining results from 17 studies on insomnia in China, a pooled prevalence of 15.0% is reported for the country. This result is consistent among other

East Asia East Asia is the eastern region of Asia, which is defined in both geographical and ethno-cultural terms. The modern states of East Asia include China, Japan, Mongolia, North Korea, South Korea, and Taiwan. China, North Korea, South Korea and ...

n countries; however, this is considerably lower than a series of

Western countries The Western world, also known as the West, primarily refers to the various nations and states in the regions of Europe, North America, and Oceania.

(50.5% in Poland, 37.2% in France and Italy, 27.1% in USA). Men and women residing in China experience insomnia at similar rates. A separate meta-analysis focusing on this sleeping disorder in the elderly mentions that those with more than one physical or psychiatric malady experience it at a 60% higher rate than those with one condition or less. It also notes a higher prevalence of insomnia in women over the age of 50 than their male counterparts. A study that was resulted from a collaboration between

Massachusetts General Hospital Massachusetts General Hospital (Mass General or MGH) is the original and largest teaching hospital of Harvard Medical School located in the West End neighborhood of Boston, Massachusetts. It is the third oldest general hospital in the United Stat ...

and

Merck Merck refers primarily to the German Merck family and three companies founded by the family, including: * the Merck Group, a German chemical, pharmaceutical and life sciences company founded in 1668 ** Merck Serono (known as EMD Serono in the Unite ...

describes the development of an

algorithm In mathematics and computer science, an algorithm () is a finite sequence of rigorous instructions, typically used to solve a class of specific Computational problem, problems or to perform a computation. Algorithms are used as specificat ...

to identify patients with sleep disorders using electronic medical records. The algorithm that incorporated a combination of structured and unstructured variables identified more than 36,000 individuals with physician-documented insomnia. Insomnia can start off at the basic level but about 40% of people who struggle with insomnia have worse symptoms. There are treatments that can help with insomnia and that includes medication, planning out a sleep schedule, limiting oneself from caffeine intake, and cognitive behavioral therapy.

Obstructive sleep apnea

Obstructive sleep apnea Obstructive sleep apnea (OSA) is the most common sleep-related breathing disorder and is characterized by recurrent episodes of complete or partial obstruction of the upper airway leading to reduced or absent breathing during sleep. These episod ...

(OSA) affects around 4% of men and 2% of women in the United States. In general, this disorder is more prevalent among men. However, this difference tends to diminish with age. Women experience the highest risk for OSA during pregnancy, and tend to report experiencing depression and

in conjunction with obstructive sleep apnea. In a meta-analysis of the various Asian countries, India and China present the highest prevalence of the disorder. Specifically, about 13.7% of the Indian population and 7% of Hong Kong's population is estimated to have OSA. The two groups in the study experience daytime OSA symptoms such as difficulties concentrating, mood swings, or high blood pressure, at similar rates (prevalence of 3.5% and 3.57%, respectively).

Sleep paralysis

systematic review A systematic review is a Literature review, scholarly synthesis of the evidence on a clearly presented topic using critical methods to identify, define and assess research on the topic. A systematic review extracts and interprets data from publ ...

states 7.6% of the general population experiences

sleep paralysis Sleep paralysis is a state, during waking up or falling asleep, in which one is conscious but is completely paralyzed. During an episode, one may hallucinate (hear, feel, or see things that are not there), which often results in fear. Episodes ...

at least once in their lifetime. Its prevalence among men is 15.9%, while 18.9% of women experience it. When considering specific populations, 28.3% of students and 31.9% of psychiatric patients have experienced this phenomenon at least once in their lifetime. Of those psychiatric patients, 34.6% have

panic disorder Panic disorder is a mental disorder, mental and Abnormal behavior, behavioral disease#Disorder, disorder, specifically an anxiety disorder characterized by reoccurring unexpected panic attacks. Panic attacks are sudden periods of intense fear th ...

. Sleep paralysis in students is slightly more prevalent for those of Asian descent (39.9%) than other ethnicities (Hispanic: 34.5%, African descent: 31.4%, Caucasian 30.8%).

Restless leg syndrome

According to one meta-analysis, the average prevalence rate for North America and Western Europe is estimated to be 14.5±8.0%. Specifically in the United States, the prevalence of

restless leg syndrome Restless legs syndrome (RLS), also known as Willis-Ekbom disease (WED), is generally a long-term disorder that causes a strong urge to move one's legs. There is often an unpleasant feeling in the legs that improves somewhat by moving them. This ...

is estimated to be between 5% and 15.7% when using strict diagnostic criteria. RLS is over 35% more prevalent in American women than their male counterparts.

References

External links

*
Sleep Problems
– information leaflet from mental health charity The Royal College of Psychiatrists
WebMD
Sleep Disorders Health Center {{Authority control