Updated March 1, 1999

What is advanced sleep phase syndrome?

Advanced sleep phase syndrome is a disorder in which the major sleep episode is advanced in relation to the desired clocktime, that results in symptoms of compelling evening sleepiness, an early sleep onset, and an awakening that is earlier than desired.

What are the symptoms?

There is a chronic inability to stay awake in the evening or sleep later into the morning hours.

The major complaint may concern either the inability to stay awake in the evening, or early morning awakening insomnia, or both.

Unlike other sleep maintenance disorders, the early morning awakening occurs after a normal amount of undisturbed sleep.

Unlike other causes of excessive sleepiness, daytime school or work activities are not affected by sleepiness.

However, the evening activities are cut short by the need to retire much earlier than the social norm.

Typical sleep onset times are between 6 and 8 p.m., and no later than 9 p.m., and wake times between 1 and 3 a.m., and no later than 5 a.m. These sleep-onset and wake times occur despite the patient's best efforts to delay sleep to later hours.

How does this affect a person?

There can be negative personal or social consequences that are due to leaving activites in the early to mid-evening hours in order to go to sleep.

Attempts to delay sleep onset to a time later than usual may result in embarrassment due to falling asleep during social gatherings, or more seriously from drowsiness or falling asleep while driving in the evening.

Individuals with advanced sleep phase syndrome who attempt to work evening or night shifts would have difficulty staying awake during the evening and early morning hours.

If chronically forced to stay up later for social or vocational reasons, the early awakening aspect of the syndrome could lead to chronic sleep deprivation and daytime sleepiness or napping.

Who gets advanced sleep phase syndrome?

It is more likely to appear in the elderly.

How is it treated?

Advanced sleep phase syndrome is treated with chronotherapy or bright light therapy. Chronotherapy would involve a systematic advancement of bedtime until the desired bedtime is achieved. Bright light therapy would involve inducing a phase delay and the light exposure must be in the early evening. There is not a lot of data about the effectiveness of light therapy for ASPS.


Diagnostic Classification Steering Committee, Thorpy MJ, Chairman. International Classification of Sleep Disorders: Diagnostic and Coding Manual. Rochester, Minnesota: American Sleep Disorders Association, 1990.

Kryger, Meir H., Roth, Thomas, Dement, William C. Principles and Practice of Sleep Medicine, 2nd Edition. Philadelphia, Pennsylvania: W.B. Saunders Company, 1994.

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