The Different Types of Circadian Rhythm Sleep Disorder

1. The Different Types Of
Circadian Rhythm Sleep
Disorder
Published on March 24, 2017
Lisa Marie Cannon
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4 articles Follow
The circadian rhythm is more often referred to as “body
clock.” It is the set of biological rhythms governing the

2. physiological and behavioral changes in the body; its
most common feature is the sleep-wake cycle. These
rhythms are typically in-sync with nature’s light-dark
cycle, which results in humans needing to sleep during
the night and wake up in the morning.
When there is an abnormality in the length, timing, or
rigidity in a person’s natural sleep-wake cycle, that
individual may be suffering from a circadian rhythm
sleep disorder (CRSD). Disorders falling under this
category should be diagnosed and treated appropriately as
they often lead to psychological and functional
difficulties.

3. Image source: chronobiology.com
There are six types of CRSD, which are categorized into
either intrinsic (chronic with neurological causes) or
extrinsic (due to social or environmental circumstances).
Intrinsic

4. Delayed sleep phase syndrome (DSPS): The individual’s body clock is delayed
relative to the day and night cycle. He is unable to sleep until it is very late at night,
usually after midnight.
Advanced Sleep Phase Syndrome (ASPS): Opposite of DSPS, those with ASPS feel
the need to sleep much earlier than the usual bedtime.
Non-24-hour sleep-wake syndrome (Non-24): This causes an out-of-sync circadian
rhythm, conditioning the body to have a day length longer than 24 hours.
Irregular sleep-wake disorder (ISWD): Individuals who suffer from ISWD cannot
sleep seven to nine hours straight. Instead, they require at least three sleep periods in a
day, with each period lasting for about two to three hours only.
Extrinsic
Shift-work sleep disorder: A person’s circadian rhythm is affected when he has to
work in a shift different than the traditional 9-to-5. This leads to difficulty in adjusting
to the required schedule of sleep.

5. Jet lag: When a person travels across locations of different time zones, his body has to
temporarily adjust to the different day-night cycle.
Lisa Marie Cannon, M.D. is an internist specializing in
various fields including sleep medicine.