Circadian rhythm sleep disorder

Credit: wikipedia.org

Circadian rhythm sleep disorders (CRSD), a family of sleep disorders, affect (among other bodily processes) the timing of sleep. People with circadian rhythm sleep disorders are unable to go to sleep and awaken at the times commonly required for work and school as well as social needs. They are generally able to get enough sleep if allowed to sleep and wake at the times dictated by their "body clocks". The quality of their sleep is usually normal unless they also have another sleep disorder.

Humans, like most living organisms, have various biological rhythms. Circadian rhythms, often referred to as the body clock or the biological clock, control processes that re-occur daily, e.g. body temperature, alertness, and hormone secretion as well as sleep timing. Due to the circadian clock, sleepiness does not continuously increase throughout the day; a person's desire and ability to fall asleep is influenced both by the length of time since the person woke from an adequate sleep and by internal circadian rhythms. Thus, a person's body is ready for sleep and for wakefulness at relatively specific times of the day.

Sleep researcher Yaron Dagan states that "[t]hese disorders can lead to harmful psychological and functional difficulties and are often misdiagnosed and incorrectly treated due to the fact that doctors are unaware of their existence".

Types of circadian rhythm sleep disorders

Extrinsic type

One of these disorders is extrinsic (from Latin extrinsecus, from without, on the outside) or circumstantial:

• Shift work sleep disorder, which affects people who work nights or rotating shifts.

Formerly, jet lag, too, was classified as an extrinsic type circadian rhythm disorder.

Intrinsic type

Four of them are intrinsic (from Latin intrinsecus, on the inside, inwardly), "built-in":

• Advanced sleep phase disorder (ASPD), aka advanced sleep phase syndrome (ASPS), characterized by difficulty staying awake in the evening and difficulty staying asleep in the morning
• Delayed sleep phase disorder (DSPD), aka delayed sleep phase syndrome (DSPS), characterized by a much later than normal timing of sleep onset and offset and a period of peak alertness in the middle of the night
• Irregular sleep–wake rhythm, which presents as sleeping at very irregular times, and usually more than twice per day (waking frequently during the night and taking naps during the day) but with total time asleep typical for the person's age
• Non-24-hour sleep–wake disorder (non-24, aka hypernychthemeral syndrome), in which the affected individual's sleep occurs later and later each day, with the period of peak alertness also continuously moving around the clock from day to day.  Read more >>

Source: https://en.wikipedia.org/wiki/Circadian_rhythm_sleep_disorder