November 30th, 2010
01:41 PM ET
I hear the floorboards creak, the toilet flush, first one shoe drop to the floor, then the other. My husband pulls back the covers and climbs into bed, disturbing the dog, who now spins around rattling her tags looking for a new, cozy den. I groan and turn over to look at the clock: 3 a.m., an early night for him. You see, my husband is what many people call a "night owl," but really he suffers from a circadian rhythm sleep disorder called delayed sleep phase disorder.
Circadian rhythm means a 24-hour cycle. Humans have a 24-hour sleep/wake cycle that is linked to the 24-hour cycle of the sun. So, in the optimal situation, we rise in the morning and after about 16 hours of wakefulness we are sleepy and we go to bed and sleep for eight hours. In my last blog, I talked about shift work disorder and how shift workers are not able, because of their jobs, to flow with this natural rhythm.
People with delayed sleep phase disorder also get out of sync with what we would consider normal bed times (10 p.m. to midnight), but for unknown reasons. The exact prevalence in the general population is unknown, but it is estimated to affect 7 percent to 16 percent of teens and young adults.
Delayed sleep phase disorder usually begins in adolescence or early adulthood. Sleep onset is delayed at least two hours from social norms, and these altered sleep/wake times can impair the work, academic and social parts of sufferers' lives. People with DSPD often complain of insomnia because they try to go to sleep at a normal time but their internal rhythm is set to a later time and sleep is usually impossible until very late. Then, if they have to get up for work or school, they are very tired and sleepy in the daytime and are not functioning at their highest capabilities. Often, they will steal a nap, but that only sets them up for further delay in their bedtime.
Usually the patients who show up at the sleep center are teens who are brought in by their mothers because they can't get up and make it to their early morning classes. Their grades are failing and the school is threatening to expel them. How do I help them? Well, I must return to my near-constant theme: Light.
We get them on a schedule where we slowly move up their bedtimes - just 15-30 minutes each time over a series of weeks. With each change in bedtime, they are instructed to be sure to avoid bright light two hours before the desired bedtime. We often need to use glasses that filter the blue light because it is not realistic to think that teenagers are not going to be on the computer or using some electronic device. I also have them get outside and get some bright light in the mornings. Where I am in Chicago, for much of the year we recommend that such patients use light boxes in the morning. I recommend the ones made by Lite Book because they use LED technology, which means they are smaller and patients need to spend only 15-30 minutes in front of the unit.
We also use melatonin, but not as a sleep aid. Instead, we use it to alter people's circadian rhythm, and therefore, we give it 5-7 hours before desired bedtime and we use small doses (0.5-1.0 mg). And I always recommend that they try this at home the first few times in case it makes them sleepy right away.
I would like to caution that although this general principle of bright light in the morning and dim light before bedtime is easy enough to understand, it is also easy to apply the principle incorrectly and actually make matters worse. For example, a well-meaning mother of a 16-year-old reads this and tomorrow morning hauls her son out of bed at 6:30 a.m. to get him to his first AP class. The next night, to her dismay, he stays up even later, and getting him up the following morning would require inviting the marching band to hold practice in his bedroom.
What has gone wrong? Well, when mom got him up at 6:30 a.m., he had only had 4½ hours of sleep and his core body temperature had not reached its low point. When his eyes received bright light before the lowest drop in core body temperature, then the internal clock in the brain was being reset to a later time and actually delaying the sleep onset for the next night. Many times we have to wait until a vacation to try to reset someone's clock. Most times, the help of a sleep physician is essential, and always, the patients themselves have to want to change their schedule.
Another word of caution: It is easy to confuse this disorder with insomnia, but just giving the young person a sleeping pill doesn't usually work to reset the internal clock.
Why do some teens have these dramatic shifts in sleep onset and not others? This can run in families and changes in one of the circadian clock genes have been associated with this disorder but we cannot yet point to a specific genetic mutation that causes this problem. Delayed sleep phase can be associated with depressive symptoms but the good news is: Many will naturally outgrow it, especially when the responsibilities of adult life force them into becoming morning people. Some, like my husband, will return to their nocturnal ways every chance they get.
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