Delayed Sleep-Wake Phase Disorder (DSWPD) in Children and Adolescents
What is delayed sleep-wake phase disorder (DSWPD)?
Delayed sleep-wake phase disorder (DSWPD) is a disorder in which a person's sleep is delayed by two 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 pm and waking at 6:30 am, an adolescent with DSWPD will fall asleep well after midnight and have great difficulty getting up in time for school.
Most children and adolescents with DSWPD 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.
Symptoms and Causes
What causes delayed sleep-wake phase disorder (DSWPD)?
The exact cause of this disorder is not completely known. However, approximately 7% to 16% of adolescents have DSWPD. Thus, it is a common disorder. Scientists think DSWPD may be an exaggerated reaction to the normal shift in the internal clock that is seen in many adolescents after puberty. It is important to understand that this is not a deliberate behavior. DSWPD most commonly occurs during adolescence, but cases have been reported during childhood; it is rare for it to begin after early adulthood.
What are the signs and symptoms of delayed sleep-wake phase disorder (DSWPD)?
Symptoms of DSWPD include:
- Inability to fall asleep at the desired time. This usually presents as insomnia complaints. It may be heightened 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 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 DSWPD often experience excessive daytime sleepiness as a result of not getting enough sleep, at least on weekdays.
- Generally no sleep problems if allowed to maintain their desired sleep/wake schedule. If uncomplicated by other sleep disorders, children and adolescents with DSWPD 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. Children and adolescents with DSWPD often sleep well during vacations or school breaks when there is no pressure to wake at a certain time. Sleep maintenance is not an issue.
- Depression and behavior problems. Children and adolescents with DSWPD 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.
Diagnosis and Tests
How is delayed sleep-wake phase disorder (DSWPD) diagnosed?
DSWPD is diagnosed based solely on a description of the symptoms and sleep logs. Sometimes a non-invasive wrist-watch-like device called an actigraph 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. Sophisticated tests of melatonin or core temperature rhythms are generally reserved for research purposes.
Management and Treatment
How is delayed sleep-wake phase disorder (DSWPD) treated?
Treatment for DSWPD involves the following:
- Good sleep habits. Children and adolescents with DSWPD need to do everything they can to develop and maintain good sleep habits and a consistent sleep schedule. Habits should include going to bed and waking up at the same times including on weekends and vacations; avoiding caffeinated products (coffees, teas, colas, some non-cola pops, energy drinks, chocolates, and some medications [Excedrin®]); avoiding other stimulants and products that can disrupt sleep (alcohol, sleeping pills, nicotine); maintaining a cool, quiet and comfortable bedroom; and avoiding activities before bedtime that are stimulating (computer games, smart phone, television use).
- Shifting the bedtime schedule. Treatment for DSWPD 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 on the following night and so on.
- Delaying the internal clock. This method moves the bedtime sequentially 1 to 3 or more hours 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.
- 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 internal clock under control but does not "cure" the tendency toward a delayed sleep-wake phase. Once the desired bedtime 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 sticking to the schedule can there be some flexibility allowed on special occasions.
- 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.
- Medications. Melatonin or other natural sleep-inducing drugs are another option some physicians may try.