Delayed Sleep Phase Disorder, one of the most common circadian rhythm disorders, affects an estimated 15% of adolescents and adults.

What is Delayed Sleep Phase disorder?

Delayed sleep phase disorder is a condition in which the onset of sleep is delayed by 2-3 hours each night. For instance, if the normal bedtime were 10 o’clock, a person suffering from Delayed Sleep Phase Disorder wouldn’t be able to fall asleep until midnight or later. People suffering from this condition often have difficulty waking up in the morning for work or school, and may suffer from daytime drowsiness or fatigue.

What are the Symptoms of Delayed Sleep Phase?

Individuals suffering from Delayed Sleep Phase Disorder generally don’t sleep until the early morning hours, and often report feeling more alert and awake when performing tasks late at night. They may even describe themselves as “night owls”. If their schedule during the week permits, they sleep until late morning and report feeling well rested. In reality, however, the demands of school or work lead to sleep deprivation during the week (from sleeping fewer hours than would be natural). To compensate, these individuals often nap during the day or sleep excessively on the weekends. Symptoms may include:

  • Insomnia or excessive sleepiness
  • Inability to fall asleep at the desired time
  • Inability to wake up at the desired time
  • Depression or anxiety
  • An altered sleep pattern which been present for 3 months or more

How Did I Get Delayed Sleep Phase?

Normally, the body’s internal clock adjusts and resets to changes in sleeping patterns. In delayed sleep phase, this clock fails to adapt or does so slowly. For most individuals, falling asleep later than usual (for example working on a project or attending a social activity) results in an adjustment in their body’s internal clock, and on subsequent days, they are able to fall asleep and wake up as desired. In delayed sleep phase, the body maintains its pattern of falling asleep later than usual (regardless of how physically tired the individual is). Factors thought to contribute to the condition include:

  • Family History (three times more likely with a positive family history)
  • Too little sunlight in the morning
  • Too much bright evening light

How is it Diagnosed?

If you experience any of the above symptoms, consult a sleep specialist. Tests he may order include:

  • Sleep log- through the sleep log, the characteristic pattern of delayed sleep will be evident.
  • Actigraph-A watch-like device that tracks sleep-wake behavior at home.
  • Polysomnogram- A diagnostic test that may be ordered if your physician suspects a different sleep disorder. It monitors brain activity, eye movements, oxygen, heart rate, and breathing as you sleep.


What is the Treatment for Delayed Sleep Phase?

Treatment may include the following:

  • Sleep Hygiene- Your physician may recommend proper sleep hygiene. Good habits include maintaining a consistent pattern of falling asleep and waking up, avoiding caffeine and stimulants, and creating a relaxing environment in your bedroom which promotes sleep. These habits can be reinforced by adding relaxing rituals (i.e. peaceful music, massage, or bath soak) prior to bedtime.
  • Bright light therapy: This method involves exposing the individual to bright lights in the morning (approximately half an hour) while bright light exposure in the evening is minimized.
  • Chronotherapy-A behavioral method which delays bed time by 3 hours consistently each day until the desired bedtime is reached. Once this happens, the schedule is then frozen, and the individual is encouraged to maintain the current sleep-wake cycle.
  • Medication-Melatonin is a substance created by the brain to help regulate our sleep-wake cycle. Your doctor may recommend melatonin to aid in treating Delayed Sleep.