Home » Sleep Disorders » Advanced Sleep-Wake Phase
November 2020 |  Reviewed by:  Seema Khosla, MD and Rafael Sepulveda, MD

What is advanced sleep-wake phase disorder?

Advanced sleep-wake phase disorder (ASP) is one of several circadian rhythm sleep-wake disorders. These disorders occur in people who sleep at times that seem to be out of order with “normal” sleep times. People with ASP have an “early bird” circadian clock. They fall asleep several hours before a normal bedtime. As a result, they also wake up hours earlier than most people wake in the morning.

People with ASP feel sleepy in the late afternoon. Bedtime tends to occur between 6 p.m. and 9 p.m. Since bedtime is early, they also wake up early. They tend to wake up between 2 a.m. and 5 a.m. While the timing of sleep is early, sleep itself is normal.

All the biological changes related to sleep also occur at early times. This includes an earlier release of melatonin and other hormones. The body temperature curve is also moved earlier. This has been used as a marker to detect this disorder.

Some people with ASP can follow this early schedule. Problems often occur when social plans take place during the late afternoon or evening. This makes them struggle to stay awake. They may appear very sleepy to others during these evening hours. Missing a few hours of evening sleep over time can cause chronic sleep deprivation. This results in true sleepiness. Even when deprived of sleep, people with ASP still tend to wake up early.

People with ASP may mistake their problem for something else. They may think that waking up too early is a sign of either insomnia or depression. They may worry about being awake so early. It is hard for them to be awake at a time when others are asleep.

People with ASP may adjust their lifestyles or jobs around their natural “early bird” clock. For example, an “early bird” clock would be ideal for working the early shift. This includes jobs such as a baker or surgeon. Other people with ASP do things to worsen their condition. They try to realign their early clock to match the schedules of others. For example, they may drink too much coffee or take stimulants to stay awake at night. They may also try to stay asleep during the morning hours. To do this, they may drink alcohol or take sleeping pills. These choices will only make their sleep worse.

What are symptoms of advanced sleep-wake phase disorder?

Someone with ASP may:

  • Fall asleep during the late afternoon or early evening AND wake up too early while everyone else is still sleeping
  • Feel very sleepy in the late afternoon AND very alert in the early hours of the morning
  • Awaken and fall asleep before they would like to

It is also important to know if there is something else that is causing your sleep problems. They may be a result of one of the following:

  • Another sleep disorder
  • A medical condition
  • Medication use
  • A mental health disorder
  • Substance abuse