Living with Chronic Pain

What Is Delayed Sleep Phase Syndrome?


The human body experiences cyclical changes, known as circadian rhythms, during the span of a 24-hour day. The most recognizable circadian rhythm is the sleep-wake cycle. The brain receives cues from the environment, primarily changes in light, to prepare the body for restful sleep.

When the sleep-wake cycle is disrupted to the point that everyday activities are affected, it is considered a circadian rhythm disorder. One such disorder is “delayed sleep phase syndrome (DSPS).” This condition is characterized by at least a two-hour delay (going to sleep at a later time and waking at a later time) in comparison to a standard sleep-wake cycle. It is important to note that individuals with this DSPS do not choose to stay up late; their circadian rhythm, or internal clock, is delayed by two hours or more.


Symptoms of delayed sleep phase syndrome must be present for at least three months in order for a diagnosis to be made. The primary symptom of this condition is a sleep-wake cycle that is delayed at least two hours. Other symptoms include the following:

  • Insomnia
  • Difficulty waking in the morning
  • Excessive daytime sleepiness
  • Difficulty showing up for morning events, such as work, school, or appointments
  • Irritability or other mood changes
  • Difficulty staying awake and alert during the day
  • Difficulty concentrating, focusing, or remembering


Research suggests that a genetic component is involved in delayed sleep phase syndrome. Cues from the environment and certain lifestyle choices can also potentially influence a person’s sleep-wake cycle, including the following:

  • Eating habits
  • Light/dark exposure
  • Physical activity
  • Biological factors

Risk factors

Delayed sleep phase syndrome is most common among teenagers and young adults. Other biological factors increase the risk of DSPS, including the following:

  • Assigned female at birth and between the ages of 40 and 60
  • Experienced symptoms in childhood (90% of adults with DSPS had symptoms as children.)
  • Family history of DSPS
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