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What Are Circadian Rhythm Disorders?

Irregular Sleep Patterns May Cause Insomnia, Excessive Daytime Sleepiness


Updated February 05, 2014

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What Are Circadian Rhythm Disorders?

A man uses a light box to treat his seasonal affective disorder.

Christopher Furlong / Getty Images

Difficulties falling asleep or staying awake at the proper times may suggest you have a problem with your biological clock called a circadian rhythm disorder, but what are circadian rhythm disorders? These common conditions may include wanting to sleep at an atypical time, irregular sleep patterns, and even jet lag or shift-work sleep disorder.

Features of Circadian Rhythm Disorders

The circadian rhythm disorders share common characteristics. They occur when your internal biological clock becomes out of sync with external time cues such as the natural dark-light cycle. As a result, your desire to sleep may shift away from nighttime. Therefore, you may have difficulties with insomnia or excessive daytime sleepiness. The inability to sleep at the expected time coupled with sleepiness during wakefulness may lead to difficulties with job and school performance. For a better understanding of this, review the disorders and examples provided below:

Diagnosis and Treatment

Circadian rhythm sleep disorders often result when the desire to sleep is misaligned with the day-night cycle. This may occur in medical conditions such as blindness or as the result of long-distance air travel or even from working the graveyard shift. Fortunately, the conditions are easily diagnosed by using sleep logs and actigraphy and effective treatments including behavioral changes, light boxes, and melatonin can be helpful.


American Academy of Sleep Medicine. "International classification of sleep disorders: Diagnostic and coding manual." 2nd ed. 2005.

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