Circadian Rhythm Sleep Disorder

Do you know anyone having difficulties in sleeping at night or who sleeps and wakes at different times than others? Chances are that the person is suffering from Circadian Rhythm Sleep Disorder. Read and know all about the types, causes and treatments of the condition.

Circadian Rhythm Sleep Disorder Definition

It refers to a family of several types of sleep disorders that affects sleep timing. People suffering from this condition fail to go to sleep and wake up at normal times. This affects their social needs and even various everyday activities such as going to school or workplace. However, they usually get as much sleep as required if they are allowed to fall asleep and wake up at the times their bodies want to.

Circadian Rhythm Sleep Disorder Prevalence

CRSD affect infants, children and adults. However, the exact frequency of this disorder is yet unknown.

Circadian Rhythm Sleep Disorder Types

The group of disorders is classified into two categories:

Picture of Circadian Rhythm Sleep Disorder

Picture 1 – Circadian Rhythm Sleep Disorder

Extrinsic Category

Extrinsic refers to something that originates outside an organism or a system rather than within it. Two types of this condition, which may occur from non-organic origin, are:

Jet Lag

The condition usually arises when an individual travels to east or west for several hours or crosses many time zones. The body may require several days to adjust to the environment of the new time zone. This disorder is named so as it occurs due to prolonged travelling in jet aircrafts.

Shift Work Syndrome

Individuals suffering from this syndrome have various problems with alertness, sleep and appetite. It occurs when a person works in a shift when he or she should be asleep according to the circadian rhythms.

Intrinsic category

Intrinsic disorders refer to conditions that occur within an organism or a system. There are 4 intrinsic types of CRSDs. These can be caused due to heredity or by some disease or serious head injury. These conditions are usually chronic and cannot be cured completely, although proper treatment helps keep the symptoms in check. Read on to know more about the four intrinsic types of this disorder:

Advanced Sleep-Phase Syndrome (ASPS)

It is a very rare type of CRSD. Individuals suffering from ASPS start feeling sleepy during early evening and go to bed at around 7 pm or 8 pm. They wake up at around 3 am in the morning. The quality of their sleep is normal. It is common for several members of a same family to have Advanced Sleep-Phase Syndrome.

Delayed Sleep-Phase Syndrome (DSPS)

This is a common CRSD and can be described as the opposite of Advanced Sleep-Phase Syndrome. Its offset generally occurs during early childhood or puberty. People with DSPS generally go to sleep between 3 am and 6 am. They cannot wake up before 12 in the noon, which means they cannot attend school or job in the morning. Sometimes, the symptoms subside as an individual reaches his or her 20s. However, this does not mean the syndrome is cured after 20 years of age as it is a chronic condition.

Non-24-Hour Sleep-Wake Syndrome (Non-24)

It is another extremely rare type of CRSD, generally affecting blind people. Sometimes, it also affects people with normal sight. Non-24 patients are not able to adjust to the regular light/dark cycle. Due to this reason, they sleep 1 to 2 hours later than the previous day and take the same duration to wake up after the time that they usually get up at. The times of their appetite, alertness, hormone cycles and body temperature rhythm change continuously and return to a particular time every few weeks. This pattern is known as “Free Running Sleep”.

Irregular Sleep-Wake Disorder

Another rare type of CRSD, it may occur due to various factors, such as some type of mental handicap, head injury and dementia. Irregular sleep-wake disorder patients sleep and wake many times in a single day. However, these times vary every day.

Circadian Rhythm Sleep Disorder Causes

These sleep disorders can occur due to various different causes. Difference in the normal sleeping demands and the natural sleep-wake cycle of a person and a change in the sleep-wake schedule are the two main causes of the disorder. CRSD may also occur due to pregnancy. Other common factors causing the condition include:

  • Shift work
  • Pregnancy
  • Time zone changes
  • Medications
  • Changes in routine

Circadian Rhythm Sleep Disorder Symptoms

Know about some of the main symptoms associated with each type of CRSD:

Jet Lag

  • Feeling disoriented all the time
  • Tiredness and fatigue
  • Staying awake during night
  • Difficulties in concentration
  • Loss of drive
  • General malaise
  • Headache

Delayed Sleep-Phase Syndrome

  • Feeling Sleepy when one should be awake
  • Excessive sleepiness or Insomnia
  • Difficulty in attending the morning activities

Advanced Sleep Phase Syndrome

  • Reduced alertness during daytime
  • Sleepiness during evening
  • A tendency of waking up earlier than the desired time

Shift Work Sleep Disorder

  • Excessive sleepiness
  • Increase in the stress levels
  • Difficulty in concentration
  • Insomnia
  • Lack of energy
  • Headache
  • Mood related problems like irritability

Circadian Rhythm Sleep Disorder Prevention

The disorder mainly occurs due to various environmental factors, such as:

  • Travelling long distances
  • Working in shifts
  • Following a lifestyle that disrupts sleep

It is possible to prevent the condition by avoiding these stress factors.

Circadian Rhythm Sleep Disorder Tests and Diagnosis

Physicians generally ask patients to record their sleep and wake timings and hand it over to them so that they can study the sleep-wake patterns. It is only after studying these patterns that a doctor can ascertain whether his/her patient require a complete diagnosis. A sleep lab observation may also be carried out. Physicians try to find the mismatch between the circadian sleep-wake pattern of the patient and the pattern required by his or her environment.

The diagnosis of CRSD must not be confused with the normal adjustments made by a person to match his or her schedule. An individual should be suffering from persistent and recurring sleep disruptions, affecting his or her social and occupational activities, to be positively diagnosed with this condition.

Circadian Rhythm Sleep Disorder Treatment and Management

Treatment depends on the type of sleep disorder that a person is suffering from. The main goal of all the treatment options is to alter the sleep patterns of the patient in a way that would allow the person to maintain a normal lifestyle. People suffering from Shift Work and Jet Lag type of CRSDs are able to reduce the symptoms by travelling less frequently or returning to normal work schedule. The treatment options for CRSD include:

Lifestyle Changes

Adjusting and changing some aspects of the daily life, such as exposure to daylight, can help one combat the disorder better. Changing the daily routine and strategically scheduling the nap times enable a person to cope better with the sleep disorder.

Sleep Hygiene

Doctors instruct about developing a healthy sleeping habit instead of using drugs and alcohol in order to bring about sleepiness in CRSD patients.

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Picture 2 – Circadian Rhythm Sleep Disorder Image

Bright Light Therapy

This is among the most common therapies used for treating CRSD. In Bright Light Therapy, the eyes are exposed to a safe level of bright, intense light for a brief period at specific times in a day in order to synchronize the body clock.


Sometimes, doctors may prescribe a hypnotic medicine to a CRSD patient for promoting sleep. Stimulants can be used for promoting wakefulness.


The brain produces a hormone named “Melatonin” which is believed to be very important for maintaining the normal sleep-wake cycle. CRSD patients are sometimes prescribed with doses of this hormone to relieve the condition.


The behavioral technique used for gradually adjusting the bedtime in a systematic manner is known as Chronotherapy. This helps alter the sleep-wake cycle of the patient to achieve the desired bedtime.

Circadian Rhythm Sleep Disorder Prognosis

It is very difficult for CRSD patients to change their sleeping and waking patterns and maintain them for long duration. Patients often experience a reversal of the symptoms approximately 2 weeks after achieving a normal sleep and wake schedule. Generally, however, the treatments have a positive outcome.

In case of hereditary CRSDs, the therapies cannot completely cure the condition. Chronic CRSDs caused by some head trauma or disease cannot be cured as well. However, the symptoms of both these types of CRSD can be kept in check by proper treatment.


Circadian Rhythm Sleep Disorders can seriously affect the daily life of an individual. However, proper treatment helps reduce its symptoms and allows patients to lead a normal life.



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