What is delayed sleep phase syndrome (DSPS)?
Delayed sleep phase syndrome (DSPS) is a disorder in which a person’s sleep is delayed by 2 or more hours beyond the socially acceptable or conventional bedtime. This delay in falling asleep causes difficulty in waking up at the desired time. As an example, rather than falling asleep at 10:00 p.m. and waking at 6:30 a.m., an adolescent with DSPS will fall asleep well after midnight and have great difficulty getting up in time for school.
Most children and adolescents with DSPS describe themselves as "night owls" and say they function best or are most alert during the evening or night hours. If they were to keep a sleep log it would show short sleep periods during the school/work week (with few or no awakenings during the night) and lengthy sleep-ins (late morning to mid afternoon wake up times) on the weekend.
What causes delayed sleep phase syndrome (DSPS)?
The exact cause of this disorder is not completely known. However, approximately 7% to 16% of adolescents have DSPS, making it a common disorder. Scientists think DSPS may be an exaggerated reaction to the normal shift in the internal clocks that is seen in adolescents after puberty. It is important to understand that this is not deliberate behavior, but that certain habits can make this condition worse. DSPS most commonly occurs during adolescence, but cases have been reported during childhood.
What are the signs and symptoms of DSPS?
Symptoms of DSPS include:
- Inability to fall asleep at the desired time. This usually presents as insomnia complaints. It may be exacerbated by the social pressures teenagers feel to stay up late (homework, internet or cell phone use).
- Inability to wake up at the desired time and excessive daytime sleepiness. Usually this is the most common complaint because it is more readily evident to parents than the nighttime insomnia. Because of the delay in falling asleep and yet still needing to get up at the required time for work or school, children or adolescents with DSPS often experience excessive daytime drowsiness as a result of not getting enough sleep (most evident on weekdays). The delayed rhythm is coupled with a delay in the cycle of the night hormone melatonin, which lingers in the morning and makes it harder to wake up.
- Generally no other sleep problems. If uncomplicated by other sleep disorders, children and adolescents with DSPS sleep well through the night with few or no awakenings once they fall asleep. They simply suffer from a shift in their internal clock or sleep-wake cycle – pushing it later by 2 or more hours. Sleep maintenance is not an issue. When allowed freedom to keep their delayed bed and wake times, they wake up without help, refreshed and without any problems with sleepiness.
- Depression and behavior problems. Children and adolescents with DSPS may experience depression and other psychiatric problems including behavioral problems as a result of daytime drowsiness and missing school. Daytime drowsiness can also lead to lowered academic performance from missed school days or tardiness and inattention. Dependency on caffeine, sedatives or alcohol may also be seen.
How is delayed sleep phase syndrome (DSPS) diagnosed?
DSPS is diagnosed based solely on a description of the symptoms and sleep logs. Sometimes a non-invasive wrist-watch-like device called an autograph may be used to confirm rest-activity rhythms. An overnight sleep study (polysomnogram) may be recommended to rule out the presence of any other sleep disorders if the history is suggestive. Sophisticated tests of melatonin or core temperature rhythms are generally reserved for research purposes.
How is delayed sleep phase syndrome (DSPS) treated?
Treatment for DSPS involves the following:
- Good sleep habits. Children and adolescents with DSPS need to do everything they can to develop and maintain good sleep habits and a steady sleep schedule. Habits should include going to bed and waking up at the same times on weekends as on weekdays; avoiding caffeinated products (eg, coffees, teas, colas, some non-cola pops, energy drinks, chocolates, and some medications [Excedrin®]); avoiding other stimulants and products that can disrupt sleep (eg, alcohol, sleeping pills, nicotine); maintaining a cool, quiet and comfortable bedroom; and avoiding activities before bedtime that are stimulating (eg, computer games and television).
- Shifting the bedtime schedule. Treatment for DSPS can involve one of two methods: advancing or delaying the internal clock.
- Advancing the internal clock. This method simply moves the bedtime a bit earlier on each successive night until the desired bedtime is reached. For example, setting the bedtime at midnight on one night, 11:45 p.m. on the next night, 11:30 p.m. on the following night and so on. This is facilitated by concomitantly moving the wake time to allow this transition to occur with more control. These methods are best individualized with the help of a sleep specialist.
- Delaying the internal clock (“Chronotherapy”). This method moves the bedtime sequentially 1-3 hours or more later on successive nights until the desired bedtime is reached. This requires several days free from social activities and may be best attempted during a long school break or vacation period. The thinking behind this strategy is that it is much easier for the body to adjust to a later bedtime than an earlier one. Again, this is best done with advice from a sleep specialist.
- Staying motivated to stick with the schedule. It is especially important not to lose sight of the goals during holidays and weekends. Adhering to strict bed and wake times keeps the body’s clock under control but does not "cure" the tendency for delayed sleep phase. Once the desired bedtime/wake time is reached, your child or adolescent must stay motivated and stick with going to bed at the desired bedtime on a nightly basis in order to reset the internal clock. Only after several months of adhering to the schedule can there be some flexibility allowed on special occasions. However, efforts should be made to wake up close to the prescribed wake time to keep the rhythm going, regardless of when the adolescent goes to sleep.
- Bright light therapy. Some physicians recommend bright light therapy, which requires the purchase of special light box. Exposing your child to bright light for approximately half an hour in the morning helps to reset the body’s internal clock. Reduced exposure to bright light in the evening also helps. Your sleep doctor will be able to suggest commercially available light boxes and the correct method of use.
- Avoidance of light at night. Any screen time with a back light (hand held devices, computers, TV etc.) can theoretically delay the sleep rhythm and make it harder to go to sleep. These should be avoided in the few hours prior to bed time, especially when trying to shift the rhythm.
- Medications. Melatonin or other natural sleep-inducing drugs are another option that may be tried with the help of a sleep specialist.
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