Delayed Sleep-Wake Phase Disorder

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What is Delayed Sleep-Wake Phase Disorder?

A small percentage of the population may have natural “night owl” tendencies. But consistently staying awake until very late at night, and regularly oversleeping in the morning, may signal a circadian rhythm sleep disorder called delayed sleep-wake phase disorder (also called delayed sleep-wake phase syndrome).

Delayed sleep-wake phase disorder occurs when the circadian rhythm shifts and sleep occurs later in the 24-hour cycle. People with delayed sleep-wake phase disorder generally fall asleep after midnight, night after night, and cannot wake up in the morning in time for work or school. They experience experience excessive daytime sleepiness, which can result in depression and behavioral problems.

Symptoms of Delayed Sleep-Wake Phase Disorder

People with this sleep disorder generally experience:

  • Inability to fall asleep until 2 hours or more past normal bedtime
  • Complaints of insomnia
  • Excessive daytime sleepiness that interferes with work or school
  • Dependence on caffeine and/or sleeping pills
  • Depression or behavioral problems resulting from excessive daytime fatigue
  • No other sleep disorders

How Common is Delayed Sleep-Wake Phase Disorder?

Delayed sleep-wake phase disorder is more common than advanced sleep-wake phase disorder, but this may stem from the fact that delayed sleep-wake phase disorder is more likely to interfere with school or work, so people are more likely to seek treatment. Adolescents experience a natural sleep phase delay during puberty, and as many as 16 percent of teenagers have delayed sleep-wake phase disorder, which is more common in girls than boys.

What Causes Delayed Sleep-Wake Phase Disorder?

Like other circadian rhythm sleep disorders, delayed sleep-wake phase disorder is a neurological condition involving changes to the brain’s regulation of sleep patterns. Because it appears most often in adolescents, scientists believe the circadian shift is linked to naturally occurring changes in hormone levels after puberty.


Delayed sleep-wake phase disorder is generally diagnosed using self-reported symptoms. Doctors may ask for a patient’s sleep diary to evaluate sleep patterns and sleep hygiene. In some cases, polysomnography or actigraphy are used to determine whether another sleep disorder is causing symptoms.


Delayed sleep-wake phase disorder is generally treated through a combination of behavioral therapy and light therapy to shift the circadian rhythm.

  • Improved sleep hygiene, particularly establishing and sticking to a consistent sleep-wake schedule, can help treat delayed sleep-wake phase syndrome.
  • Using a light box in the morning and avoiding bright light at night can help regulate sleep patterns in people with delayed sleep-wake phase syndrome.
  • Melatonin and other sleep aids can help induce sleep earlier in the evening, helping to promote a more consistent sleep schedule.

Additional Resources
Light Therapy
Your Body’s Circadian Rhythm, Explained

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