Delayed Sleep Phase Syndrome
Delayed Sleep Phase Syndrome (DSPS) is believed to be a disorder of the body's timing system – the biological clock. Difficulty falling asleep and difficulty waking come from the biological clock being out of phase with the sleeping and waking times the DSPS patient tries to carry out. DSPS is similar to jet lag but is much longer-lasting. It can develop suddenly or gradually.
You probably have heard of a biological clock which governs growth, reproductive cycles and aging. There are also bodily rhythms, known as circadian rhythms, which are controlled by a biological clock and work on a daily time scale.
You might have already noticed in yourself or in others that sleepiness doesn't just keep increasing as it gets later. Rather, the drive for sleep follows a cycle, and the body is ready for sleep and for wakefulness at different times of the day.
DSPS is found in persons who get a normal or nearly normal amount of sleep, but the entire sleep cycle is shifted later than normal. For example, sleeping routinely between 4 a.m. and noon is an example of delayed sleep phase syndrome.
If you think you might have DSPS and consider it a problem, you should start to keep a sleep log so a doctor can evaluate your symptoms. This takes a few minutes every day.
You should write down:
- Time you tried to fall asleep
- Time you think you fell asleep
- Any nighttime awakenings
- Time you woke up
- Time you had to be up
- Whether you got up by yourself, by an alarm clock or because you were disturbed
- A few words about how you felt during the day
- Any daytime naps – how long and when
- What medications you used
It is easier to distinguish DSPS from other causes of inadequate sleep if the sleep log is recorded when the patient is not taking sleeping pills, sedatives of any kind or stimulants, such as caffeine. But if your doctor has already recommended one of these types of medication for you, continue to take it as directed until your doctor agrees it is safe for you to stop.
At least 2 weeks of sleep logs are needed to diagnose DSPS. Many sleep clinics encourage new patients to bring a family member, roommate or friend to the 1st visit. An overnight stay in a sleep lab is usually not necessary, except to rule out other sleep disorders.