What Is Non-24-Hour Sleep-Wake Disorder?

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Non-24-hour sleep-wake disorder is a type of circadian rhythmsleep disorder. The circadian rhythm is a 24-hour sleep cycle your body follows. People with this condition have a circadian rhythm typically shorter or longer than 24 hours.

While most people sleep at about the same time every day, a person with this disorder will find that their sleep time is gradually delayed every day. Over time, living with this disorder can lead to health challenges. People with this condition also find it difficult to adhere to regular schedules, which affects work, school, and social obligations.

What Is a Circadian Rhythm Sleep Disorder?

Symptoms of Non-24-Hour Sleep-Wake Disorder

This condition can look a little different from person to person. Symptoms also range in severity. N24SWD progresses gradually, and so do its symptoms. This means that symptoms of the condition are less severe when it first develops. The most common symptoms of the disorder include:

People with N24SWD may not always experience these symptoms. Sometimes theirdelayed sleep patternsmight eventually align with the regular day-night cycle, allowing a person with this condition to get a full night of rest and be up and functioning in the morning.

However, if the condition goes untreated, the cycle continues to shift until it once again becomes desynchronized with the usual 24-hour cycle.

Diagnosis

N24SWD is more likely to affect people who are blind. As a result, it’s often misdiagnosed in people with sight. Its symptoms are also similar to several other sleeping disorders. To make a conclusive diagnosis, your doctor will take a detailed history of the symptoms you’ve been exhibiting. They’ll also consider your family and medical history.

At the same time, N24SWD isn’t necessarily a genetic disorder. Some research points to genetic factors contributing to its development. If you have a history of drug or alcohol misuse, it’s also essential to disclose this to your doctor.

You might be asked to keep a sleep diary, recording your sleep and wake times for a couple of weeks. If your doctor suspects another medical condition may be responsible for your symptoms, they’ll request additional tests like blood work or a CT scan.

Actigraphy is used to measure sleep-wake cycles. It’s used for diagnosing some sleep disorders. It involves you wearing a watchlike device round the clock for a week or two. The device records inactive and active periods of sleep, which can help your doctor establish a pattern of sleep disturbance.

Causes

It’s unclear what exactly is responsible for N24WD’s development. Over the years, scientists have come up with some plausible theories. What is clear is that light and the way we perceive light plays a significant role in the development of this condition.

In the morning, your body senses that it’s bright and wakes you, resetting your body’s sleep-wake clock until the next time you sleep. This is why you are more likely to sleep longer in a pitch dark room even if it’s already day.

Blindness

This is the most commonly researched cause of N24SWD. People who are blind don’t possess the ability to perceive light. As a result, they’ll fail to notice light signals that help your body fine-tune its circadian rhythm.

Some research estimates that around 55%-70% of people who are blind may have N24SWD.However, not all blind people are at risk of developing this disorder. Some blind people retain the ability to perceive light.

Sensitivity to Light

N24SWD is more likely to occur in people who are blind. However, it can also occur in people with sight in certain cases. One is that people with sight could be hypersensitive or insensitive to light which may affect their circadian rhythms.

Treatment

Treatment aims at restoring your body’s regular sleep-wake cycle.Bright light therapyis another treatment option that may be considered for people with this condition who have light perception. However, this treatment option is only effective for sighted people or people with blindness who can perceive light.

Coping With Non-24-Hour Sleep-Wake Disorder

Maintaining regular sleep-wake times is challenging for a person with this disorder. The inability to perceive light has been identified as a significant causative factor in the development of N24SWD. However, there are other ways tohelp your body reset its circadian cyclebesides light. Some tips to help you achieve this include:

A Word From Verywell

N24SWD can be a disruptive condition, interrupting your daily functioning and causing problems for you at home, school, or work. If you suspect you or a loved one has this condition, you should speak to a medical professional about it.

5 SourcesVerywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.NORD (National Organization for Rare Disorders).Non-24-hour sleep-wake disorder.2017Genetic and Rare Diseases Information Center.Non 24 hour sleep wake disorder.November 8, 2021Emens JS, Eastman CI.Diagnosis and treatment of non-24-h sleep–wake disorder in the blind.Drugs. 2017;77(6):637-650. doi:10.1007/s40265-017-0707-3U.S. National Library of Medicine.HETLIOZ- tasimelteon capsule.December 10, 2020Malkani RG, Abbott SM, Reid KJ, Zee PC.Diagnostic and treatment challenges of sighted non–24-hour sleep-wake disorder.J Clin Sleep Med. 2018;14(4):603-613. doi:10.5664%2Fjcsm.7054

5 Sources

Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.NORD (National Organization for Rare Disorders).Non-24-hour sleep-wake disorder.2017Genetic and Rare Diseases Information Center.Non 24 hour sleep wake disorder.November 8, 2021Emens JS, Eastman CI.Diagnosis and treatment of non-24-h sleep–wake disorder in the blind.Drugs. 2017;77(6):637-650. doi:10.1007/s40265-017-0707-3U.S. National Library of Medicine.HETLIOZ- tasimelteon capsule.December 10, 2020Malkani RG, Abbott SM, Reid KJ, Zee PC.Diagnostic and treatment challenges of sighted non–24-hour sleep-wake disorder.J Clin Sleep Med. 2018;14(4):603-613. doi:10.5664%2Fjcsm.7054

Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

NORD (National Organization for Rare Disorders).Non-24-hour sleep-wake disorder.2017Genetic and Rare Diseases Information Center.Non 24 hour sleep wake disorder.November 8, 2021Emens JS, Eastman CI.Diagnosis and treatment of non-24-h sleep–wake disorder in the blind.Drugs. 2017;77(6):637-650. doi:10.1007/s40265-017-0707-3U.S. National Library of Medicine.HETLIOZ- tasimelteon capsule.December 10, 2020Malkani RG, Abbott SM, Reid KJ, Zee PC.Diagnostic and treatment challenges of sighted non–24-hour sleep-wake disorder.J Clin Sleep Med. 2018;14(4):603-613. doi:10.5664%2Fjcsm.7054

NORD (National Organization for Rare Disorders).Non-24-hour sleep-wake disorder.2017

Genetic and Rare Diseases Information Center.Non 24 hour sleep wake disorder.November 8, 2021

Emens JS, Eastman CI.Diagnosis and treatment of non-24-h sleep–wake disorder in the blind.Drugs. 2017;77(6):637-650. doi:10.1007/s40265-017-0707-3

U.S. National Library of Medicine.HETLIOZ- tasimelteon capsule.December 10, 2020

Malkani RG, Abbott SM, Reid KJ, Zee PC.Diagnostic and treatment challenges of sighted non–24-hour sleep-wake disorder.J Clin Sleep Med. 2018;14(4):603-613. doi:10.5664%2Fjcsm.7054

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