Circadian rhythm sleep disorder facts for kids

Circadian rhythm sleep disorders happen when your body's natural clock, called the circadian rhythm, gets out of sync. This can make you sleep and wake up at unusual times. Even though you might get enough sleep, it's at times that don't fit with most people's schedules.

These disorders don't just affect sleep. Your circadian rhythm also controls other important things. It helps manage your appetite, body temperature, and even your hormone cycles.

Outside Influences on Sleep

"Extrinsic" means something that comes from outside your body. There are two types of circadian rhythm sleep disorders caused by outside influences:

Jet Lag

Jet lag often affects people who travel quickly across many time zones, like flying east or west. Your body's internal clock expects one time, but the local time is very different. It can take several days for your body to adjust to the new time. The name "jet lag" comes from traveling by jet aircraft.

Shift Work Syndrome

Many people work during times when their body naturally wants to be asleep. This is called shift work. For example, working late at night can cause health problems. Most people who work past midnight find it hard to stay awake and feel their best. Their bodies are trying to sleep, but they have to work.

Inside Influences on Sleep

"Intrinsic" means something that comes from inside your body. There are four types of circadian rhythm sleep disorders that usually come from within. Unless they are caused by a head injury, they are often genetic. This means people are born with them. These conditions are usually long-lasting, but sometimes they can be treated.

Advanced Sleep-Phase Syndrome

Advanced sleep-phase syndrome (ASPS) is very rare. People with ASPS feel sleepy very early in the evening. They might go to sleep around 7:00 PM or 8:00 PM. Then they wake up very early in the morning, like 3:00 AM or 4:00 AM. Often, several people in the same family have ASPS.

Delayed Sleep-Phase Syndrome

Delayed sleep-phase syndrome (DSPS) is more common than ASPS. It affects about 0.15% of adults. This condition usually starts when someone is a young child or during puberty. Some cases that begin in puberty might go away when the person is around 20 or 21 years old. DSPS is much more common in teenagers than in adults. If DSPS continues past age 20, it usually lasts for life.

People with DSPS cannot fall asleep before 3:00 AM to 6:00 AM, or even later. This makes it hard for them to wake up in time for school or a job that starts in the morning. However, they can go to sleep and wake up at the same late times every day. This means their bodies are entrained (adjusted) to the daily light/dark cycle. Even when they try to sleep at "normal" times, they feel most awake late at night.

Non-24-Hour Sleep-Wake Syndrome

Non-24-hour sleep-wake syndrome (Non-24) is quite rare. People with Non-24 have very unusual sleep times. Their sleep and wake times are not controlled by daylight. They are not entrained (adjusted) to the daily light/dark cycle. This is called freerunning sleep.

For people who can see, Non-24 is often the most challenging circadian rhythm sleep disorder. Their "daily" rhythm lasts 25 hours or more. This means they sleep and wake up one or more hours later each day. Their appetite, body temperature, and hormone cycles also keep shifting around the clock. They only return to the same time after a few weeks.

About half of totally blind people, who cannot see any light, have Non-24. Their daily rhythm is not exactly 24 hours. It does not adjust to the natural light/dark cycle because they cannot see light. This condition can often be treated.

Irregular Sleep-Wake Disorder

Irregular sleep-wake disorder is rare. It is often possible to find out what causes it. For example, it can be caused by a head injury or certain health conditions. People with this disorder sleep and wake up several times a day. Their sleep times are not the same each day. They sleep about 8 hours a day in total, but never all at once.

Treatment Options

Treatment for these disorders often does not work perfectly. Also, it can be difficult to find a doctor who knows a lot about circadian rhythms. This area of study is still quite new.

Bright Light Therapy

Treatment with bright light is also called phototherapy or light therapy. People with ASPS need a lot of bright light in the evening. They should try to avoid bright light in the morning. People with DSPS need bright light as soon as they wake up. They should try to avoid bright light before bedtime.

Melatonin

Melatonin is a hormone made in a part of the brain called the pineal gland. It is normally only produced in the evening and at night. People with ASPS can take melatonin by mouth in the morning. People with DSPS can take melatonin in the afternoon or evening. This treatment also works for some people with Non-24.

You can buy melatonin in shops in the USA and Canada. In most other countries, you need to get it from a doctor. In some places, it might not be legal to buy it without a prescription.

See also

In Spanish: Trastorno del sueño del ritmo circadiano para niños