Sleep state misperception

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 generally show normal sleep patterns. Though the sleep patterns found in those with SSM have long been considered indistinguishable from those without, some preliminary research suggest there may be subtle differences (see Symptoms and diagnosis: Spectral analysis). Patients are otherwise generally in good health, and any illnesses—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." The validity and reliability of sleep state misperception as a pertinent diagnosis has been questioned, with studies finding poor empirical support. Sleep state misperception is classified as an intrinsic dyssomnia. 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: report short sleep (subjective insomnia complaint without objective findings) or no sleep at all (subjective total insomnia) report excessive daytime sleepiness (subjective sleepiness complaint without objective findings) report sleeping too much (subjective hypersomnia without objective findings) The validity and reliability of the sleep state misperception as a pertinent medical entity was questioned.