Revealed: The Five Types of Circadian Rhythm Sleep Disorders

by Martin Reed Patient Advocate

All-too-often we use the term “insomnia” to describe all manner of sleep disturbances. If you find yourself falling asleep and waking at odd hours, you may be living with a circadian rhythm disorder.

What are circadian rhythm disorders?

We all have a built-in body clock known as the circadian rhythm. For most of us, it runs on an (approximately) 24-hour cycle. A disruption in this cycle or a mismatch with the external environment can lead to a circadian rhythm disorder.

General symptoms

If you feel as though you sometimes suffer from insomnia, and sometimes suffer with daytime sleepiness, your internal body clock may not be appropriately aligned with the day-night cycle.

Shift work sleep disorder

This condition is associated with those who tend to be awake and working when their bodies are expected to be asleep. It can lead to insomnia and excessive sleepiness.

How to treat shift work disorder

The best treatment for this condition is to stick to a regular sleep/wake cycle. If that's not possible, rotating shifts every two weeks in a forward direction may help. Naps can help if kept to less than 30 minutes. Exposure to bright light in the evening and restriction of bright light in the morning may help.

Delayed sleep phase disorder

This is characterized by the inability to fall asleep until late at night and difficulty waking in the morning. Those with this disorder may find it difficult to wake in the morning and are commonly referred to as night owls.

How to treat delayed sleep phase disorder

Exposure to bright light early in the morning for 30-90 minutes may help, especially when combined with light restriction in the evenings. Glasses that block blue light in the evening may also be helpful.

Advanced sleep phase disorder

This is characterized by the inability to stay awake until bedtime and finding it difficult to stay asleep in the morning. As a result, individuals tend to go to bed very early in the evening and wake very early in the morning.

How to treat advanced sleep phase disorder

Exposure to bright light in the evenings can help maintain alertness and reset bedtimes to a more appropriate hour.

Irregular sleep-wake rhythm

Those with this condition will tend to get the right amount of sleep for their age, but they will get no real sleep cycle rest during the night. Instead, sleep comes from numerous naps, with no pattern of sleep and wakefulness.

How to treat irregular sleep-wake rhythm

Practicing good sleep hygiene such as keeping a regular bedtime and wake time can help. Furthermore, trying to stick to a regular routine during the day (for example, eating times and activity times) can also help.

Non-24-hour sleep-wake disorder

Individuals with this sleep condition have variable sleep patterns. Most sufferers are blind; as a result their internal body clock is completely out of sync with the external environment.

How to treat non-24-hour sleep-wake disorder

Melatonin and melatonin receptor agonists may help improve sleep patterns in blind individuals. For sighted individuals, exposure to bright light in the morning can help.

A few additional words about melatonin

There is inconsistent evidence for melatonin as a treatment for sleep disorders. The U.S. Department of Health and Human Services found little difference between melatonin and placebo. In fact, higher doses can lead to daytime sleepiness, depression, and sleep disturbance.

Martin Reed
Meet Our Writer
Martin Reed

Martin is the creator of Insomnia Coach, an eight-week course that combines online sleep education with individual sleep coaching. His course helps clients improve their sleep so they can enjoy a better life with more energy and start each day feeling happy, healthy, rested, and refreshed. Martin also runs a free sleep training course that has helped over 5,000 insomniacs. He holds a master’s degree in health and wellness education and studied clinical sleep health at the University of Delaware.