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Delayed Sleep Phase Syndrome

Delayed sleep phase syndrome (DSPS) by definition is a sleeping disorder that causes people to be unable to fall asleep until the early morning hours (usually between midnight and 3 a.m.) and then have difficulty waking in the morning. DSPS is not life threatening and does not affect general health.

People with delayed sleep phase syndrome can fall asleep quite easily in the early morning hours when they become sleepy. If they try to force themselves to change their sleeping pattern, unpleasant symptoms result, including:

altered eating habits
fatigue
sleep onset insomnia
sleepiness during the day.

Causes of Delayed Sleep Phase Syndrome

No one knows the exact cause of DSPS. Currently, sleep experts know that DSPS is a disorder that affects the body's circadian rhythms, which regulate the internal clock and regulate sleep-wake patterns. People who are more likely to develop delayed sleep phase syndrome include:

head trauma victims
individuals who have recently suffered serious illness
teenagers.

While DSPS is often found in teenagers, the majority of them outgrow the condition. Since the cause of delayed sleep phase syndrome is unknown, there are no current strategies for prevention.

Symptoms of DSPS

Delayed sleep phase syndrome is characterized by:

delay in falling asleep (usually between midnight and 3 a.m.)
difficulty waking in the morning
peak alertness and creativity at different times in the day and night
poor performance in morning activities such as school or work.

Some people with DSPS turn to alcohol or sedatives to try to fall asleep earlier in the evening when school or work begin in the early morning. Use of these substances is not helpful and usually complicates the condition.

Diagnosing Delayed Sleep Phase Syndrome

No diagnostic tests exist for DSPS since it leaves no physical evidence in the body. Doctors are able to diagnose the condition by learning the sleep history of the patient. Often, doctors will ask patients to keep a sleep diary for about two weeks to record their sleep histories. Information recorded in a sleep diary usually includes:

bedtime
how long it takes to fall asleep
how one feels when waking up
napping practices
number and length of awakenings during the night.

Actigraphy is another diagnostic tool doctors may use to help identify DSPS. It involves a monitoring device, usually worn on the wrist over a period of time. Actigraphy measures:

circadian rhythm
motion and stillness
pain response
response to any medication.

Information collected by the monitoring device is recorded and analyzed to identify whether or not sleep-wake patterns indicate delayed sleep phase syndrome.

Treating DSPS with Bright Light Therapy

Because circadian rhythms are sensitive to light, DSPS is often treated with bright light therapy. Exposure to bright light in the early morning can advance sleep onset at night and lead to easier awakening in the morning. Light can be delivered through the use of a light box. This device emits white light at 5,000 to 10,000 lux. When using light therapy, many factors need to be tailored for the individual patient, including:

Distance from light: Sitting further away can diminish effectiveness.
Timing: Light exposure is more effective at earlier hours, and individual effects vary.
Total time of treatment: Effective duration of light therapy treatments varies from patient to patient. Some patients require as much as an hour of light each morning, while other patients may find 15 minutes effective.

Patients who feel confined by a light box may opt for a light visor, which allows them to walk around during treatment.

Treating DSPS with Chronotherapy

Chronotherapy treats DSPS by manipulating the sleep-wake cycle to adjust circadian rhythm. In chronotherapy, the patient goes to sleep and wakes up three hours later each day until his sleep schedule has advanced around the clock to the desired bedtime.

Resources

About, Inc. (2008). Advanced or Delayed Sleep Phase Syndrome. Retrieved January 19, 2008, from the About.com Web site: http://sleepdisorders.about.com/library/bldsps.htm.

HealthCommunities.com, Inc. (2000). Delayed Sleep Phase Syndrome. Retrieved January 19, 2008, from the Sleepchannel.com Web site: http://www.sleepdisorderchannel.com/dsps/treatment.shtml.

The Cleveland Clinic (2008). Delayed Sleep Phase Syndrome and Advanced Sleep. Retrieved January 19, 2008, from the Cleveland Clinic Web site: http://www.clevelandclinic.org/health/health-info/docs/3700/3714.asp?index=12116.

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