Sleep state misperception
Encyclopedia
Sleep state misperception (SSM) is a term in the International Classification of Sleep Disorders
(ICSD) most commonly used for people who mistakenly perceive their sleep
as wakefulness, though it has been proposed that it be applied to those who severely overestimate their sleep time as well ("positive" sleep state misperception). While most sleepers with this condition will report not having slept in the previous night at all or having slept very little, clinical recordings demonstrate normal sleep patterns. Moreover, patients are otherwise generally in good health, and any ills—such as depression—appear to be more associated with fear of negative consequences of insomnia ("insomnia phobia") than from any actual loss of sleep.
Sleep state misperception was adopted by the ICSD to replace two previous diagnostic terminologies
: "subjective insomnia complaint without objective findings" and "subjective sleepiness complaint without objective findings."
Other synonyms of the term include: paradoxical insomnia, pseudo-insomnia, subjective insomnia, subjective sleepiness, and sleep hypochondriasis.
. While SSM is regarded a sub-type of insomnia
, it is also established as a separate sleep-condition, with distinct pathophysiology
. Nonetheless, the value of distinguishing this type of insomnia from other types is debatable due to the relatively low frequency of SSM being reported.
Sleep state misperception can also be further broken down into several types, by patients who—
s or prevention, though it is believed to be most prevalent among young to middle aged adults.
Distribution among the general population and by gender
is unknown. About 5% of the clinical population is affected, though that figure is subject to sampling bias.
This sleep disorder
frequently applies when patient
s report not feeling tired despite their subjective
perception
of not having slept. Alternatively, patients may report excessive daytime sleepiness
or insomnia, while lacking factors often associated with those symptoms such as sleep apnea
syndrome
or nocturnal sleep disturbance. Generally, they may describe experiencing several years of no sleep, short sleep, or non-restorative sleep. Otherwise, patients appear healthy, both psychiatrically
and medically
. (That this condition is often asymptomatic
could explain why it is relatively unreported.)
However, upon clinical observation, it is found that patients may severely overestimate the time they took to fall asleep
—often reporting having slept half the amount of time indicated by polysomnogram or electroencephalography
(EEG), which may record normal sleep. Thus, it becomes evident that the perception of poor sleep is primarily illusion
ary. Moreover, reports of daytime sleepiness may be a result of the nocebo
response—the reverse of the placebo
effect—due to patient expectations of adverse effects from their subjective perception of poor sleep.
Due to the subjective nature of this complaint, which depends on patient self-reporting of sleep, it is not currently measurable by objective means. One woman affected by SSM began contemplating suicide “because no one can figure out what is wrong with me” after being repeatedly dismissed as normal by various doctors and receiving insomnia treatments that did not work from others.
A recent study published in the journal Psychosomatic Medicine has shown that sleep misperception (i.e., underestimation of sleep duration) is prevalent among chronic insomniacs who sleep objectively more than 6 hours in the sleep lab. The psychological profile of these chronic insomniacs with objective normal sleep duration is characterize by depressive, anxious-ruminative traits and poor coping resources. Thus, it appears that not all chronic insomniacs underestimate their sleep duration, and that sleep misperception is a clinical characteristics of chronic insomniacs with objective normal sleep duration. Furthermore, rumination and poor coping resources may play a significant role in sleep misperception.
hypnotics may also help relieve the symptom
s. Additionally, education about normal patterns of the sleep-wake cycle
may alleviate anxiety
in some patients. For patients with severe depression resulting from the fear of having insomnia, electroconvulsive therapy
appears to be a safe and effective treatment.
of hypnotic
s or stimulant
s may lead to drug dependency
as a complication.
Nonetheless, chronic SSM may increase risk for depression, anxiety, and substance abuse
. It has also been noted that patients with this condition may sometimes opt to take medications over other treatments "for the wrong reasons (e.g. because of euphoriant properties)."
, unlike SSM, can be confirmed empirical
ly through clinical testing, such as by polysomnogram. In other words, those who experience SSM may believe that they have not slept for extended periods of time, when they in fact do sleep but without perceiving so.
Moreover, cases of objective total insomnia are extremely rare. The few that have been recorded have predominantly been ascribed to a rare incurable genetic disorder called fatal familial insomnia
, which patients rarely survive for more than 26 months after the onset of illness—often much less. While rarer cases of objective total insomnia
lasting for decades have been reported, such as with the American Al Herpin
and the Vietnamese Thai Ngoc
, they have not been studied extensively in a clinical setting.
International Classification of Sleep Disorders
The International Classification of Sleep Disorders is "a primary diagnostic, epidemiological and coding resource for clinicians and researchers in the field of sleep and sleep medicine."...
(ICSD) most commonly used for people who mistakenly perceive their sleep
Sleep
Sleep is a naturally recurring state characterized by reduced or absent consciousness, relatively suspended sensory activity, and inactivity of nearly all voluntary muscles. It is distinguished from quiet wakefulness by a decreased ability to react to stimuli, and is more easily reversible than...
as wakefulness, though it has been proposed that it be applied to those who severely overestimate their sleep time as well ("positive" sleep state misperception). While most sleepers with this condition will report not having slept in the previous night at all or having slept very little, clinical recordings demonstrate normal sleep patterns. Moreover, patients are otherwise generally in good health, and any ills—such as depression—appear to be more associated with fear of negative consequences of insomnia ("insomnia phobia") than from any actual loss of sleep.
Sleep state misperception was adopted by the ICSD to replace two previous diagnostic terminologies
Diagnosis
Diagnosis is the identification of the nature and cause of anything. Diagnosis is used in many different disciplines with variations in the use of logics, analytics, and experience to determine the cause and effect relationships...
: "subjective insomnia complaint without objective findings" and "subjective sleepiness complaint without objective findings."
Other synonyms of the term include: paradoxical insomnia, pseudo-insomnia, subjective insomnia, subjective sleepiness, and sleep hypochondriasis.
Classification
Sleep state misperception is classified as an intrinsic dyssomniaDyssomnia
Dyssomnias are a broad classification of sleeping disorders that make it difficult to get to sleep, or to remain sleeping.Dyssomnias are primary disorders of initiating or maintaining sleep or of excessive sleepiness and are characterized by a disturbance in the amount, quality, or timing of...
. While SSM is regarded a sub-type of insomnia
Insomnia
Insomnia is most often defined by an individual's report of sleeping difficulties. While the term is sometimes used in sleep literature to describe a disorder demonstrated by polysomnographic evidence of disturbed sleep, insomnia is often defined as a positive response to either of two questions:...
, it is also established as a separate sleep-condition, with distinct pathophysiology
Pathophysiology
Pathophysiology is the study of the changes of normal mechanical, physical, and biochemical functions, either caused by a disease, or resulting from an abnormal syndrome...
. Nonetheless, the value of distinguishing this type of insomnia from other types is debatable due to the relatively low frequency of SSM being reported.
Sleep state misperception can also be further broken down into several types, by patients who—
- report short sleep (subjective insomnia complaint without objective findings)
- or no sleep at all (subjective total insomnia)
- report excessive daytime sleepinessExcessive daytime sleepinessExcessive daytime sleepiness is characterized by persistent sleepiness, and often a general lack of energy, even after apparently adequate night time sleep...
(subjective sleepiness complaint without objective findings) - report sleeping too much (subjective hypersomniaHypersomniaHypersomnia is a disorder characterized by excessive amounts of sleepiness.There are two main categories of hypersomnia: primary hypersomnia and recurrent hypersomnia...
without objective findings)
Prevalence
SSM is poorly understood. As of 2008, there is little to no information regarding risk factorRisk factor
In epidemiology, a risk factor is a variable associated with an increased risk of disease or infection. Sometimes, determinant is also used, being a variable associated with either increased or decreased risk.-Correlation vs causation:...
s or prevention, though it is believed to be most prevalent among young to middle aged adults.
Distribution among the general population and by gender
Gender
Gender is a range of characteristics used to distinguish between males and females, particularly in the cases of men and women and the masculine and feminine attributes assigned to them. Depending on the context, the discriminating characteristics vary from sex to social role to gender identity...
is unknown. About 5% of the clinical population is affected, though that figure is subject to sampling bias.
Symptoms and diagnosis
Sleep disorder
A sleep disorder, or somnipathy, is a medical disorder of the sleep patterns of a person or animal. Some sleep disorders are serious enough to interfere with normal physical, mental and emotional functioning...
frequently applies when patient
Patient
A patient is any recipient of healthcare services. The patient is most often ill or injured and in need of treatment by a physician, advanced practice registered nurse, veterinarian, or other health care provider....
s report not feeling tired despite their subjective
Subjectivity
Subjectivity refers to the subject and his or her perspective, feelings, beliefs, and desires. In philosophy, the term is usually contrasted with objectivity.-Qualia:...
perception
Perception
Perception is the process of attaining awareness or understanding of the environment by organizing and interpreting sensory information. All perception involves signals in the nervous system, which in turn result from physical stimulation of the sense organs...
of not having slept. Alternatively, patients may report excessive daytime sleepiness
Excessive daytime sleepiness
Excessive daytime sleepiness is characterized by persistent sleepiness, and often a general lack of energy, even after apparently adequate night time sleep...
or insomnia, while lacking factors often associated with those symptoms such as sleep apnea
Sleep apnea
Sleep apnea is a sleep disorder characterized by abnormal pauses in breathing or instances of abnormally low breathing, during sleep. Each pause in breathing, called an apnea, can last from a few seconds to minutes, and may occur 5 to 30 times or more an hour. Similarly, each abnormally low...
syndrome
Syndrome
In medicine and psychology, a syndrome is the association of several clinically recognizable features, signs , symptoms , phenomena or characteristics that often occur together, so that the presence of one or more features alerts the physician to the possible presence of the others...
or nocturnal sleep disturbance. Generally, they may describe experiencing several years of no sleep, short sleep, or non-restorative sleep. Otherwise, patients appear healthy, both psychiatrically
Psychiatry
Psychiatry is the medical specialty devoted to the study and treatment of mental disorders. These mental disorders include various affective, behavioural, cognitive and perceptual abnormalities...
and medically
Medicine
Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....
. (That this condition is often asymptomatic
Asymptomatic
In medicine, a disease is considered asymptomatic if a patient is a carrier for a disease or infection but experiences no symptoms. A condition might be asymptomatic if it fails to show the noticeable symptoms with which it is usually associated. Asymptomatic infections are also called subclinical...
could explain why it is relatively unreported.)
However, upon clinical observation, it is found that patients may severely overestimate the time they took to fall asleep
Sleep onset latency
In sleep science, sleep onset latency 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:...
—often reporting having slept half the amount of time indicated by polysomnogram or electroencephalography
Electroencephalography
Electroencephalography is the recording of electrical activity along the scalp. EEG measures voltage fluctuations resulting from ionic current flows within the neurons of the brain...
(EEG), which may record normal sleep. Thus, it becomes evident that the perception of poor sleep is primarily illusion
Illusion
An illusion is a distortion of the senses, revealing how the brain normally organizes and interprets sensory stimulation. While illusions distort reality, they are generally shared by most people....
ary. Moreover, reports of daytime sleepiness may be a result of the nocebo
Nocebo
In medicine, a nocebo reaction or response refers to harmful, unpleasant, or undesirable effects a subject manifests after receiving an inert dummy drug or placebo...
response—the reverse of the placebo
Placebo
A placebo is a simulated or otherwise medically ineffectual treatment for a disease or other medical condition intended to deceive the recipient...
effect—due to patient expectations of adverse effects from their subjective perception of poor sleep.
Due to the subjective nature of this complaint, which depends on patient self-reporting of sleep, it is not currently measurable by objective means. One woman affected by SSM began contemplating suicide “because no one can figure out what is wrong with me” after being repeatedly dismissed as normal by various doctors and receiving insomnia treatments that did not work from others.
A recent study published in the journal Psychosomatic Medicine has shown that sleep misperception (i.e., underestimation of sleep duration) is prevalent among chronic insomniacs who sleep objectively more than 6 hours in the sleep lab. The psychological profile of these chronic insomniacs with objective normal sleep duration is characterize by depressive, anxious-ruminative traits and poor coping resources. Thus, it appears that not all chronic insomniacs underestimate their sleep duration, and that sleep misperception is a clinical characteristics of chronic insomniacs with objective normal sleep duration. Furthermore, rumination and poor coping resources may play a significant role in sleep misperception.
Treatment
Behavioral treatment can be effective in some cases. SedativeSedative
A sedative or tranquilizer is a substance that induces sedation by reducing irritability or excitement....
hypnotics may also help relieve the symptom
Symptom
A symptom is a departure from normal function or feeling which is noticed by a patient, indicating the presence of disease or abnormality...
s. Additionally, education about normal patterns of the sleep-wake cycle
Circadian rhythm
A circadian rhythm, popularly referred to as body clock, is an endogenously driven , roughly 24-hour cycle in biochemical, physiological, or behavioural processes. Circadian rhythms have been widely observed in plants, animals, fungi and cyanobacteria...
may alleviate anxiety
Anxiety
Anxiety is a psychological and physiological state characterized by somatic, emotional, cognitive, and behavioral components. The root meaning of the word anxiety is 'to vex or trouble'; in either presence or absence of psychological stress, anxiety can create feelings of fear, worry, uneasiness,...
in some patients. For patients with severe depression resulting from the fear of having insomnia, electroconvulsive therapy
Electroconvulsive therapy
Electroconvulsive therapy , formerly known as electroshock, is a psychiatric treatment in which seizures are electrically induced in anesthetized patients for therapeutic effect. Its mode of action is unknown...
appears to be a safe and effective treatment.
Complications
The condition may worsen as a result of persistent attempts to treat the symptoms through conventional methods of dealing with insomnia. The prescriptionMedical prescription
A prescription is a health-care program implemented by a physician or other medical practitioner in the form of instructions that govern the plan of care for an individual patient. Prescriptions may include orders to be performed by a patient, caretaker, nurse, pharmacist or other therapist....
of hypnotic
Hypnotic
Hypnotic drugs are a class of psychoactives whose primary function is to induce sleep and to be used in the treatment of insomnia and in surgical anesthesia...
s or stimulant
Stimulant
Stimulants are psychoactive drugs which induce temporary improvements in either mental or physical function or both. Examples of these kinds of effects may include enhanced alertness, wakefulness, and locomotion, among others...
s may lead to drug dependency
Physical dependence
Physical dependence refers to a state resulting from chronic use of a drug that has produced tolerance and where negative physical symptoms of withdrawal result from abrupt discontinuation or dosage reduction...
as a complication.
Nonetheless, chronic SSM may increase risk for depression, anxiety, and substance abuse
Substance abuse
A substance-related disorder is an umbrella term used to describe several different conditions associated with several different substances .A substance related disorder is a condition in which an individual uses or abuses a...
. It has also been noted that patients with this condition may sometimes opt to take medications over other treatments "for the wrong reasons (e.g. because of euphoriant properties)."
Distinction from "true" insomnia
Objective insomniaInsomnia
Insomnia is most often defined by an individual's report of sleeping difficulties. While the term is sometimes used in sleep literature to describe a disorder demonstrated by polysomnographic evidence of disturbed sleep, insomnia is often defined as a positive response to either of two questions:...
, unlike SSM, can be confirmed empirical
Empirical
The word empirical denotes information gained by means of observation or experimentation. Empirical data are data produced by an experiment or observation....
ly through clinical testing, such as by polysomnogram. In other words, those who experience SSM may believe that they have not slept for extended periods of time, when they in fact do sleep but without perceiving so.
Moreover, cases of objective total insomnia are extremely rare. The few that have been recorded have predominantly been ascribed to a rare incurable genetic disorder called fatal familial insomnia
Fatal familial insomnia
Fatal familial insomnia is a very rare autosomal dominant inherited prion disease of the brain. It is almost always caused by a mutation to the protein PrPC, but can also develop spontaneously in patients with a non-inherited mutation variant called sporadic fatal insomnia...
, which patients rarely survive for more than 26 months after the onset of illness—often much less. While rarer cases of objective total insomnia
Insomnia
Insomnia is most often defined by an individual's report of sleeping difficulties. While the term is sometimes used in sleep literature to describe a disorder demonstrated by polysomnographic evidence of disturbed sleep, insomnia is often defined as a positive response to either of two questions:...
lasting for decades have been reported, such as with the American Al Herpin
Al Herpin
Al Herpin was an American known as the "Man Who Never Slept".Al Herpin, who lived in Trenton, New Jersey, claimed to have developed a rare case of insomnia, whereby he could not sleep...
and the Vietnamese Thai Ngoc
Thai Ngoc
Thai Ngoc or Hai Ngoc is a Vietnamese insomniac. According to Vietnamese news organization Thanh Nien, he is best known for his claim of being awake for 38 years. Thanh Nien also claimed that Ngoc acquired the ability to go without sleep after a bout of fever in 1973, but according to the Vietnam...
, they have not been studied extensively in a clinical setting.