Treatment for Delayed Sleep Phase Syndrome
Treatment for DSPS is aimed at re-phasing the patient's circadian rhythm and sleep pattern. The ultimate goal is to synchronize the sleep pattern to the demands of lifestyle, school, and employment to allow the patient to wake up at a given time feeling refreshed and functional.
Since the ability to wake up and function normally depends on an adequate amount of sleep, the patient gradually adjusts to an earlier bedtime. Sleep therapy of this kind usually combines proper sleep hygiene practice and external stimulus therapy. Benzodiazepines are sometimes used to modify sleep-wake patterns, but their efficacy is not proven for DSPS.
External therapeutic methods used to advance the patient's sleep phase include bright light therapy and chronotherapy. When combined, these therapies may produce significant results.
Early morning exposure to bright light tends to lead to an early wake time and advance sleep onset at night. Artificial light is often used (especially early in the morning and in the winter months) to consistently expose delayed sleep phase syndrome patients to bright light early in the morning.
Patients often receive bright light therapy (also called phototherapy) at home, with the use of a light box. A light box emits a standard dosage of 5,000 to 10,000 lux (a measure of illumination) of white light. The patient sits in front of the light at a specified distance for approximately 30 minutes to 1 hour after waking in the morning.
The dosage and timing of the light varies among patients. For instance, exposure to the light at 8 a.m. may have no effect on a certain patient, but exposing this patient to light at 7 a.m. may advance sleep onset by 1 to 3 hours. In another case, 1 hour of bright light exposure may actually cause insomnia, while 15 minutes of exposure may satisfactorily advance sleep onset.
Generally, the earlier in the day that bright light therapy is administered, the better. Most physicians recommend therapy between 6 a.m. and 8 a.m. In most cases, therapy administered at this time influences circadian rhythm and advances sleep phase more effectively.
Proximity to the light source also affects therapy. The effects are diminished by as much as 75% at twice the distance. Again, the safe, effective environment for therapy differs from patient to patient.
An alternative to the light box is a light visor. Patients who feel confined by sitting with the light box every morning may feel better walking outside while wearing the visor.
During light therapy, it is important to take the same precautions as with exposure to normal sun and bright light. Therapeutic light sources should have a UV (ultraviolet) filter and, because bright light therapy may adversely affect vision, a physician should examine the eyes prior to treatment. Some patients feel hyperactive after routine bright light therapy and others experience headache. These factors help determine individual exposure levels and frequencies.
Patients with DSPS should avoid bright light exposure in the early evening because early evening light exposure tends to delay sleep onset.
Chronotherapy was first used to treat DSPS in 1981 and was first suggested by C.A. Czeisler. This treatment is used to manipulate the sleep-wake cycle in an attempt to change the patient's underlying circadian rhythm. In chronotherapy, the patient progressively goes to bed and wakes up 3 hours later than the previous night, until he or she moves around the clock and can consistently sleep earlier.
The sleep schedule may look like this:
- 1st night: sleep at 4 a.m., wake at 12 p.m.
- 2nd night: sleep at 7 a.m., wake at 3 p.m.
- 3rd night: sleep at 10 a.m., wake at 6 p.m.
- 4th night: sleep at 1 p.m., wake at 9 p.m.
- 5th night: sleep at 4 p.m., wake at 12 p.m.
- 6th night: sleep at 7 p.m., wake at 3 a.m.
- 7th night: sleep at 10 p.m., wake at 6 a.m.
Once consistent sleep-wake habits are established, they may be adjusted slightly. Patients typically strive for a sleep time between 10 p.m. and 11 p.m. and a wake time of 7 a.m.
In most cases, it is easier to stay up longer than it is to go to sleep earlier. Delayed chronotherapy of this type takes advantage of the natural progressive shift in circadian rhythm. It is a highly effective treatment for delayed sleep phase syndrome, but is not successful in 100% of DSPS cases. Some patients cannot reset their phase cycles using this technique and a few patients experience insomnia.
Following therapy, it is important to maintain a regular, scheduled wake-up time. In fact, some clinicians believe that straying at all from a schedule nullifies the effects of chronotherapy.
Chronotherapy can interfere with prescription medications and indications associated with other disorders. For example, it should not be used in patients who take insulin or who have immune system disorders. Before beginning treatment, patients should consult a physician experienced in treating sleep disorders and the effects of combining chronotherapy with other treatments.