Delayed Sleep Phase Syndrome

What is delayed sleep phase disorder?

Delayed sleep phase disorder is a sleep disorder in which the person’s sleep-wake cycle (internal clock) is delayed by 2 or more hours. Basically, because of the shift in the internal clock by two or more hours, the ability to fall asleep is also postponed. For example, rather than falling asleep at 10 PM and waking at 7 AM, an adolescent with delayed sleep phase disorder will not fall asleep until 12 or 1 AM and then has great difficulty awakening at 7 AM for school or work. If the child or adolescent is allowed to sleep until late in the morning, he will feel rested and can function well. Most children and adolescents with delayed sleep phase disorder describe themselves as “night owls” and usually feel and function their best in the evening and nighttime hours. They usually get much less sleep on weekdays compared to weekends or holidays.

Having delayed sleep phase disorder, especially for children and adolescents who attend school, can cause significant problems, as they are unable to get up for school, often resulting in multiple school absences and tardiness.

What causes delayed sleep phase disorder?

Delayed sleep phase disorder usually develops during adolescence, but can start in childhood. It seldom occurs after the age of 30. Although the cause of delayed sleep phase disorder is not completely known, it likely is an exaggerated reaction to the normal shift in sleep times that occurs during adolescence. All adolescents have a shift in their internal clock after puberty of about two hours. In those with delayed sleep phase disorder, the clock shifts even more. In addition, for children who already had a tendency to go to bed late, this normal two-hour shift will result in a significantly shifted internal clock. It is important to realize that this shift in sleep is not caused by deliberate behavior. Unfortunately, many adolescents with delayed sleep phase disorder get labeled as noncompliant and truants. Approximately 7% of adolescents have delayed sleep phase disorder, and thus it is a common disorder.

What are the symptoms of delayed sleep phase disorder?

A child or adolescent with delayed sleep phase disorder often experiences the following symptoms.

1. Daytime sleepiness. Because of the late sleep onset times, and the usual requirement to get up earlier than desired for school or a job, children and adolescents with delayed sleep phase disorder often experience daytime sleepiness as the result of not getting enough sleep.
2. Inability to fall asleep at the desired time. On nights that children or adolescents with delayed sleep phase disorder try to go to sleep at a “normal” time, they are unable to do so. However, if they were to go to bed at their usual fall asleep time, they would have no problem falling asleep.
3. Inability to wake up at the desired time. As a result of the late sleep onset time; many children and adolescents with delayed sleep phase disorder are unable to wake up in the morning for school or other activities. This can result in many missed days or being late for school.
4. No other sleep complaints. Because the internal clock is simply shifted in children and adolescents with delayed sleep phase disorder, once asleep they sleep well with few or no awakenings. In addition, on days that they are able to sleep as long as they wish, especially on weekends or holidays, sleep is normal and daytime sleepiness is not experienced.
5. Other daytime symptoms. Some children and adolescents with delayed sleep phase disorder experience problems with depression and other behavior problems as a result of the daytime sleepiness and the effects of missing school and social activities. In addition, there are a percentage of children and adolescents with delayed sleep phase disorder who have school refusal, which complicates both diagnosis and treatment.

How is delayed sleep phase disorder diagnosed?

There is no definitive test for delayed sleep phase disorder so diagnosis is made based on the description of the problem. An overnight sleep study may be recommended to be sure that no other sleep disorder is present, such as obstructive sleep apnea or restless legs syndrome.

How is delayed sleep phase disorder treated?

Delayed sleep phase disorder is a difficult disorder to treat and requires significant effort on the part of the child or adolescent. Thus, for treatment to be successful, the child or adolescent has to be very motivated. The goal of treatment is to re-train the internal clock to a more regular schedule. Making the initial shift in the sleep-wake cycle is easier, however, than maintaining that change. Treatment can involve the following:

1. Sleep hygiene. Good sleep habits are especially important for children and adolescents with delayed sleep phase disorder. These habits should include a regular sleep schedule that includes going to bed and waking up at the same time every day; avoidance of caffeine, smoking, and other drugs; a bedroom environment that is cool, quiet, and comfortable; a bedtime routine that is calm and sleep-inducing; and avoidance of all stimulating activities before bed, such as computer games and television.
2. Shifting the internal clock. Treatment for delayed sleep phase disorder involves systematically advancing or delaying bedtime on successive nights.

1. Phase advancement. Phase advancement involves moving the bedtime earlier by 15 minutes on successive nights. If the adolescent usually falls asleep at 12:30 , then bedtime is set for 12:15 for one or two nights, 12:00 for one to two nights, and so on.
2. Phase delay (chronotherapy). Phase delay is chosen if the adolescent’s naturally occurring bedtime is 3 or more hours later than desired. Bedtime is delayed by 2 to 3 hours on successive nights. For example, if an adolescent usually falls asleep at 2 AM , bedtime is delayed until 4 AM on night one, 6 AM on night two, and so on until the desired bedtime is reached (e.g., 10:30 PM ). Given that it is much easier for the body to adjust to a later bedtime than an earlier one, it is often recommended to delay bedtime rather than try to advance it.
3. Sticking with it. Once the desired bedtime is reached, the adolescent must stick with it on a nightly basis. Even one night of late night studying or socializing can return the internal clock to being delayed. Usually, however, after several months, the schedule can become a bit more flexible.

1. Bright light therapy. Sometimes bright light therapy is recommended which involves exposure to bright light in the morning for approximately 20-30 minutes, and avoidance of bright light in the evening. Bright light in the morning will help reset the body’s internal clock. Special light boxes need to be purchased for this treatment.
2. Melatonin. Melatonin is a hormone (“Biochemical Messenger”) produced in the body that helps to regulate sleep patterns. Individuals with delayed sleep phase disorder release melatonin at a later time compared to other people. Sometimes taking a small dose (1/2 mg.) of synthetic melatonin 5-7 hours before bedtime (late afternoon) can help shift the sleep cycle to an earlier time.