Delayed Sleep Phase Syndrome

Delayed sleep phase syndrome (DSPS) is one of many circadian rhythm sleeping disorders, and is the most prevalent of all such disorders. People with delayed sleep phase have a natural inclination to go to bed later and wake up later than what is typically considered normal. It is the opposite of advanced sleep phase, in which people go to bed and wake up earlier than normal. People with delayed sleep phase generally go to bed in the early morning hours, from 1 am to 4 am, and wake up later in the morning, from 8 am to 11 am. Socially active people, and those considered ‘night owls’, who feel more awake or sharper during the evenings, are at a high rate of having or getting this disorder.

When delayed sleep phase is not the result of another sleeping disorder, people who have it will achieve sleep quality and duration equivalent to those with normal sleeping schedules. If the delayed sleep phase is not interfering with daily routines, or is in fact complimentary of the subject’s routine, it may be advised to maintain the routine, as the circadian rhythm disorder might not be harmful. When the disorder comes into conflict with daily routines, such as school or work, that requires waking up earlier than would otherwise be natural, the disorder could lead to sleep deprivation and other issues. Delayed sleep phase is responsible for 10% of all chronic insomnia cases.

People who have a delayed sleep phase which interferes with their routine often compensate by napping during the day, or sleeping excessively on weekends to counterbalance the deprived sleep during the week. This can lead to temporary relief, but perpetuates the delayed phase cycle.

Circadian rhythm disorders are caused by the body’s internal clock not resetting and adapting to changes in sleeping patterns, or doing so slowly. In most individuals, going to bed at a time different than what is normal for them will result in the circadian rhythm adjusting and allowing them to fall asleep and wake up as desired. In those with delayed sleep phase, even when suffering through lack of sleep, the body maintains its inclination to go to bed at the usual time, making it difficult to fall asleep even when feeling physically tired. Likewise the body will tend to wake up at the same time, regardless of the amount of sleep, be it too little or too much.

In contrast to advanced sleep phase, which has minimal effects on work or school obligations, people with delayed sleep phase are more likely to have their sleeping disorder interfere with their necessary daily schedule, leading to chronic sleep deprivation.  This can negatively affect school or work performance and social standing. People with DSP may be labelled as lazy, unmotivated or undisciplined.

Delayed sleep phase affects as many as 15% of teens and adults, a much higher rate than advanced sleep phase, and those with delayed sleep phase are generally younger than those with ASP. It often develops in adolescence and continues into early adulthood, though it may also begin in adulthood. It affects both genders equally. Like ASP, DSP also has a genetic link, and people with a family history of DSP are 3 times more likely to have it as those with no family history of the disorder.

Environmental conditions can lead to the development of DSP. A lack of morning sunlight exposure, and an overexposure to bright evening sunlight are likely to lead to a shift in the circadian rhythm towards a delayed sleep phase.

If delayed sleep phase is interfering with your daily schedule, it is important to take steps to minimize its effects. Nearly 50% of all reported subjects with DSP also suffer with depression. While there is no easy cure for DSP, and although DSP has shown high levels of resistance to many treatment methods, consulting a doctor should still be a priority.

The most common method of treatment is the gradual scaling back of sleeping times, until they achieve the desired timeframe. The schedule would then be rigidly implemented. While this can be effective, maintaining the new routine is imperative, as it often resets completely if the individual diverts from the new habit even once with a late night.

Bright light therapy is also an accepted treatment that has shown some positive results. It involves exposure to bright light at early morning hours shortly after waking up, and avoidance of bright outdoor light during the evening hours. This has been demonstrated to readjust the circadian rhythms of individuals to more normal schedules.

  Reviewed September, 2007

Article Reviewers