Home » Sleep Disorders » Delayed Sleep-Wake Phase
October 2020 |  Reviewed by:  Seema Khosla, MD and Andrea Matsumura, MD

What is delayed sleep-wake phase disorder?

Delayed sleep-wake phase disorder (DSP) is a circadian rhythm disorder. It consists of a typical sleep pattern that is “delayed” by two or more hours from societal norms. This delay occurs when your internal sleep clock (circadian rhythm) is shifted later at night and later in the morning. Once sleep occurs, the sleep is generally normal. But the delay leads to a pattern of sleep that is later than what is desired or considered socially acceptable. This pattern can be a problem when it interferes with work or social demands.

If you have DSP, you are likely to prefer late bedtimes and late wake-up times. When left to your own schedule, you are likely to have a normal amount and quality of sleep. It simply occurs at a later time.

One sign of DSP is difficulty falling asleep until late at night. Another sign is having a hard time getting out of bed in the morning for work or school. These signs can make DSP look like insomnia. Also, like insomnia, DSP can impair your alertness and performance during the day. It can lead to excessive sleepiness and fatigue.

What are symptoms of delayed sleep-wake phase disorder?

Symptoms of DSP include:

  • A delayed sleep pattern in relation to desired sleep and wake times
  • Trouble falling asleep at the desired bedtime
  • Inability to wake up in the morning
  • Normal duration and quality of sleep when there is no need to go to sleep or wake up at a specific time
  • A stable but delayed sleep pattern for at least seven days

It is also important to know if there is something else causing your sleep problems. Some common examples are:

  • Another sleep disorder
  • A medical condition
  • Medication use
  • A mental health disorder
  • Substance abuse

What are risk factors for delayed sleep-wake phase disorder?

The exact rate of DSP is unknown in the general population. It is much more common in teens and young adults. About 7% to 16% of teens and young adults may have DSP. DSP is likely to be found in 10% of people with a complaint of insomnia. People who tend to be “evening types” or “night owls” are likely to deve