Circadian rhythm disorders are disruptions in a person’s circadian rhythm—a name given to the “internal body clock” that regulates the (approximately) 24-hour cycle of biological processes in animals and plants. The term circadian comes from Latin words that literally mean “around the day.”

The key feature of circadian rhythm disorders is a continuous or occasional disruption of sleep patterns. The disruption results from either a malfunction in the “internal body clock” or a mismatch between the “internal body clock” and the external environment regarding the timing and duration of sleep.

Irregular Sleep Wake Rhythm:

Most people have one main period of sleep. While rare, some people have no main sleep period but instead have several napping periods each day.  The amount of sleep is often equal to people with normal sleep patterns however the deep sleep required for the bodies normal regenerative processes may not occur or be sporadic.  They may result in conflicts with professional or social obligations and result in feelings of depression or isolation.

These irregular rhythms due to the lack of deep sleep can also result in poor eating habits, memory loss and other symptoms caused by lack of deep regenerative sleep.]

Irregular sleep wake rhythm is often the result of the internal body clock malfunctioning as are many of the circadian rhythm disorders.  While rare, neurological conditions are most associated with this disorder.

Contrary to most people who will have one main sleeping period and one main period of wakefulness during a typical 24 hour stretch, people with irregular sleep-wake rhythms will have numerous instances of these periods during a typical 24 hour day. These would most often be considered naps, and they may have as many as 3-4 napping periods each day, with no main sleeping period. This sleeping pattern is most easily associated with babies, who take numerous naps throughout a day, though babies also tend to have a main sleeping period, and get as many as 12 hours or more of sleep in a typical day.

The overall amount of sleep acquired during a 24 hour period is often equal to those people with more regular sleeping patterns, but it amounts in less deep sleep, which is required for many of the body’s natural regenerative processes, and may come into conflict with social or professional obligations, leading to feelings of isolation and depression. It can further lead to the development of poor eating habits, memory loss, and other symptoms typically caused by a lack of deep sleep.

This disorder is quite rare, and is often the result of a weak body clock, as are many of the circadian rhythm disorders. It may also be the result of neurological problems, and neurological conditions such as brain damage, dementia and mental retardation may lead to the onset of this disorder.

A small study in 2013 displayed that circadian sleep disorders are more prevalent in people with MS than healthy subjects and people with higher fatigue levels are more likely than MS patients with low to moderate fatigue to occur.

Advanced Sleep Phase Disorder:

Advanced Sleep Phase Disorder (ASPD) causes people afflicted with it to have a natural tendency to go to sleep and wake up at times considered earlier than what is normal. It is one of numerous circadian rhythm sleep disorders, and is the opposite of a delayed sleep phase, in which people go to bed and wake up at times considered later than what is normal.

People with advanced sleep phase routinely go to sleep in the early evening, between 6 and 9 pm, and wake up in the early morning, ranging from 1 to 5 am.  Many people who have ASPD get quality sleep on a par with people sleeping at more normal times.

All human functions influenced by the circadian rhythm are also affected and moved forward as a result of the advanced sleep phase, including an earlier release of melatonin and other hormones, an earlier body temperature curve, and natural tendencies to eat meals earlier than usual. Many people are able to fully function in society with advanced sleep phase disorder, but others may feel alienated when forced to skip out on social gatherings that occur in the evenings, or attend them with limited faculties due to overwhelming sleepiness. This could lead to further stress and the development of additional sleeping disorders.

People with advanced sleep phase disorder may attempt to self diagnose and cure their condition by forcing late evenings, and then remaining in bed as long as possible in the mornings or taking sleeping medications to get lengthy sleep and attempt to alter their circadian rhythm. These tactics are unlikely to succeed, and may lead to other sleeping or non sleeping related issues. Those wishing to institute a permanent change to their circadian rhythm should consult a doctor or sleep specialist.

Advanced sleep phase disorder is also rare but as is the case with many sleep disorders people with neurological conditions such as multiple sclerosis can be more susceptible to the conditions.

Delayed Sleep Phase Syndrome:

Delayed sleep phase syndrome (DSPS) is the most prevalent of all such disorders. People with this condition have a natural inclination to go to bed later and wake up later than what is typically considered normal. It is the opposite of advanced sleep phasel. People with delayed sleep phase generally go to bed in the early morning hours, from 1 am to 4 am, and wake up later in the morning, from 8 am to 11 am. Socially active people, and those considered ‘night owls’, who feel more awake or sharper during the evenings, are at a high rate of having or getting this disorder.

Delayed sleep phase is responsible for 10% of all chronic insomnia cases. In contrast to advanced sleep phase, which has minimal effects on work or school obligations, people with delayed sleep phase are more likely to have their sleeping disorder interfere with their necessary daily schedule, leading to chronic sleep deprivation.

If delayed sleep phase is interfering with your daily schedule, it is important to take steps to minimize its effects. Nearly 50% of all reported subjects with DSPS also suffer with depression.

Non-24 Hour Sleep Wake Syndrome:

The most rare of the circadian rhythm disorders and most difficult to correct is the Non 24 hour sleep wake rhythm. The internal biological clock (circadian rhythm) that roughly adheres to a 24 hour with slight daily variances in waking and sleeping onset times which generally even out over time. Even those with advanced or delayed circadian rhythm disorders function within this 24 hour schedule.

The non-24-hour sleep-wake syndrome do not have internal clocks that reset and stay balanced within a 24 hour schedule. Most cases have their circadian rhythms set on longer loops, usually resulting in 25 or 26 hour cycles. There are documented cases of people having as much as 72 hour cycles where they stay awake for 48 straight hours, and then sleep for 24 straight hours as a regular sleeping pattern. There are only a few known dramatic cases such as that though, and most cases fall within the 25 or 26 hour range.

Apart from the social stress or depression that living with this disorder may cause, the disorder itself is not considered harmful. The actual quality of sleep, and more importantly deep sleep, is equal or in many cases better, than those without the disorder.

This disorder is very common among blind people, with more than 50% of blind people having it. Though they have fully functioning biological clocks, without the light cues to balance and reset it on, the circadian rhythm often becomes unbalanced. This condition is quite rare in those with sight, but can occur. Having unstructured or irregular daily routines, bad sleeping habits, and poor exposure to sunlight on a consistent basis can all be factors in the development of this disorder.

Diagnosing Circadian Rhythm Disorders:

The diagnosis of circadian rhythm disorders is challenging and often requires a consultation with a sleep specialist. Keeping a detailed sleep history and a sleep log for 1 to 2 weeks is essential. It is also important to exclude other sleep and medical disorders, including narcolepsy, which often mimics delayed sleep phase disorder.

Treatment Options:

Treatment options for circadian rhythm disorders vary based on the type of disorder and the degree to which it affects the individual’s quality of life. Individualizing the treatment of patients of circadian rhythm disorders improves the chance of success.



Melatonin is a natural hormone produced by a gland in the brain at night (when it is dark outdoors). Melatonin levels in the body are low during daylight hours and high during the night.

Melatonin supplements, available over-the-counter, may be used to enhance the natural sleep process and for resetting the body’s internal time clock when traveling through different time zones. Melatonin supplements have been reported to be useful in treating jet lag and sleep-onset insomnia in elderly persons with melatonin deficiency. However, melatonin supplements have not been approved by the FDA; therefore, it is not clear as to how much melatonin is safe and effective.

Melatonin Warning:

  • Some people, such as those with immune disorders, should consult their healthcare team before considering melatonin.
  • Melatonin may interact with other medications.
  • Consult your doctor before using melatonin.


A melatonin receptor stimulant, is also available to treat circadian rhythm disorders, but requires a doctor’s prescription. Rozerem is used to promote the onset of sleep and help normalize circadian rhythm disorders. It works differently than melatonin supplements, as it is not melatonin but a stimulator of melatonin receptors in the brain. Rozerem is approved by the FDA for treating insomnia characterized by difficulty falling asleep.

Other Medications for Circadian Rhythm Disorders:


Short-acting benzodiazepines, such as Xanax, are often prescribed in the early treatment of a circadian rhythm disorder and are used in conjunction with behavioral therapy. Long-term use of these medications is not recommended due to potential side effects, such as the rebound phenomenon (the original problem returns at a higher level), and the risk of developing a dependence on these drugs.

Nonbenzodiazepine hypnotics:

These medications, such as Ambien, Sonata, and Lunesta, are gaining popularity because they do not have a significant effect on the regular sleep cycle and are not associated with the rebound phenomenon seen with benzodiazepines. Ambien and Sonata are good short-term options for treating sleep problems, while Lunesta, a newer sleep medicine, is approved for long-term use.

Orexin receptor antagonists:

Orexins are chemicals that are involved in regulating the sleep-wake cycle and play a role in keeping people awake. This type of drug alters the action of orexin in the brain. The only approved drug in this class is Belsomra.

Non Medication Treatment options include:

Behavior Therapy: such as maintaining regular sleep-wake times, avoiding naps, engaging in a regular routine of exercise, and avoiding caffeine, nicotine, and stimulating activities within several hours of bedtime is important in the treatment of circadian rhythm disorders. People with delayed sleep phase syndrome should minimize exposure to light in the evening and during the night by reducing indoor illumination and avoiding bright TV and computer screens. Those with advanced sleep phase syndrome should increase light exposure in the evenings by keeping lights on in the home or spending time outdoors.

Bright Light Therapy: is used to advance or delay sleep. The timing of this treatment is critical and requires guidance from a sleep specialist. Bright light therapy works by resetting the circadian clock. A high intensity light (10,000 lux) is required and the duration and timing of exposure varies from 1 to 2 hours.

Medications such as melatonin, wake-promoting agents, and short-term sleep aids may be used to adjust and maintain the sleep-wake cycle to the desired schedule. Melatonin is a hormone that is available over-the-counter and is particularly effective in treating jet lag.

Chronotherapy: is a progressive advancement or delay (1 to 2 hours per day) of sleep time depending on the type and the severity of the disorder. This type of therapy requires a firm commitment on the part of the patient and caregiver as it is can take weeks to successfully shift the sleep-wake cycle. Once the desired schedule is achieved, a regular sleep-wake schedule is maintained.


There are no cures for circadian rhythm disorders however treatments such as those noted above can help mitigate the symptom.  It is important to understand that this sleep disorder is considered neurological and not psychological although if not properly addressed it can lead to psychological problems.

If you live with a circadian rhythm disorder it is ever so important towards your quality of life to work with your healthcare professionals to help try get this under control.  While it may not presently feel as though the symptom is causing problems towards your quality of life in most cases it will eventually do so and may also worsen over time.  It is important to attempt bring the condition under control as soon as possible.

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