Circadian Rhythm Sleep Disorders
What are circadian rhythm sleep disorders?
Circadian rhythm sleep disorders are a group of sleep disorders that all share the common feature of a disruption in the timing of sleep. Circadian in Latin means “around or approximately” (circa) “a day” (diem). Circadian rhythm is the name given to your body’s 24-hour “internal clock.” This internal clock controls your body’s sleep-wake cycle.
Helping to “set your internal clock” during a 24-hour day is the visual cue of light – specifically, its brightness/type of light, amount of time exposed to light, and when exposed to light. Light is transmitted through your eyes and into a specific “control center” of your brain. There are other influencers of your body’s internal clock, however, including melatonin (a hormone released in your brain that plays a role in sleep), physical activity and social behaviors. Your age can also influence your sensitivity to the sleep-wake cycle.
Circadian rhythm sleep disorders involve one of these problems:
- You have a difficult time falling asleep.
- You struggle to stay asleep and often wake up several times during the sleep cycle.
- You wake up too early and can’t go back to sleep.
What are the more common types of circadian rhythm sleep disorders?
The common types of circadian rhythm sleep disorders include:
Delayed Sleep Phase Disorder: If you have this sleep disorder, you go to sleep and wake up more than two hours later than what is typically considered a normal sleep-wake cycle. For example, you're a “night owl” who may not be able to fall asleep until 2 a.m. or later, but then sleep in until as late as 3 p.m.
Other common features of delayed sleep phase disorder are:
- You're often most alert, productive and creative late at night.
- If forced to get up early, you are sleepy during the day.
- You're often perceived as lazy, unmotivated, or a poor performer who is always late for morning responsibilities.
- Is most commonly seen in adolescents and young adults.
- May run in families.
Advanced Sleep Phase Disorder: If you have this sleep disorder, you fall asleep in the early evening (6 p.m. to 9 p.m.) and wake up in the early morning (2 a.m. to 5 a.m.).
Other common features of advanced sleep phase disorder are:
- You typically complain of early morning awakening or insomnia and are sleepy in the late afternoon or early evening.
- Is most commonly seen in the middle age and older adults.
- May run in families.
Jet Lag: If you have this sleep disorder, your body’s internal clock has been disturbed from long air travel time to a destination that is two or more time zones different from your home. This sleep-wake cycle disruption makes it difficult to adjust and function in the new time zone. Eastward travel is more difficult than westward travel because it is easier to delay sleep than to advance sleep.
Common features of jet lag are:
- Change in appetite.
- Changes in gastrointestinal (stomach and bowel) function.
- General tiredness.
- General feeling of discomfort or uneasiness and mood disturbance.
Shift Work Disorder: You may have this sleep disorder if you frequently rotate shifts or work at night. These work schedules conflict with your body’s natural circadian rhythm, making it difficult to adjust to the change. Shift work disorder is identified by a constant or recurrent pattern of sleep interruption that results in insomnia or excessive sleepiness.
Other common features of shift work disorder are:
- Ongoing tiredness.
- General feeling of discomfort or uneasiness, mood disorder.
- Gastrointestinal problems.
- Decreased sex drive.
Other health risks include increased risk of alcohol and substance abuse, weight gain, high blood pressure, heart disease and breast and endometrial cancer. This sleep disorder is most commonly seen in people who have night or early morning shifts.
Irregular sleep-wake rhythm: This sleep disorder has an undefined sleep-wake cycle. You may take several naps during a 24-hour period. Symptoms include ongoing (chronic) insomnia, excessive sleepiness or both. This disorder is more commonly seen in people with neurological conditions such as dementia, in nursing home residents, in children with intellectual disabilities and in those with traumatic injuries to the brain.
Non-24-hour sleep-wake syndrome: If you have this sleep disorder, you keep your same length of sleep and awake time, but your “internal clock” is longer than 24 hours. When this is the case, the actual sleep-wake cycle changes every day, with the time being delayed one to two hours each day. This disorder occurs most commonly in blind people.
Symptoms and Causes
What causes circadian rhythm sleep disorders?
Circadian rhythm sleep disorders are caused by continuous or occasional disruption of sleep patterns. The disruption results from either a malfunction in your “internal body clock” or a mismatch between your “internal body clock” and the external environment (for example, social and work requirements), which affects the timing and duration of sleep. This circadian mismatch causes problems functioning at work, school and in social activities.
Situations that can trigger a circadian rhythm sleep disorder include:
- Frequent changes in work shift.
- Jet lag.
- Frequent changes in time to go to bed and time to wake up.
- Brain damage resulting from such medical conditions as stroke, dementia, head injury intellectual disabilities.
- Blindness or lack of exposure to sunlight for long periods of time.
- Certain drugs.
- Poor sleep hygiene (lack of practices, habits and other factors that promote good quality sleep).
- Older age.
What are the symptoms of circadian rhythm sleep disorders?
Symptoms of circadian rhythm sleep disorders include:
Diagnosis and Tests
How are circadian rhythm sleep disorders diagnosed?
The diagnosis of circadian rhythm sleep disorders can be challenging and often requires a consultation with a sleep specialist.
Your healthcare specialist will gather information about your sleep and work schedule history and ask you to keep a sleep diary for one to two weeks. Your healthcare provider will also exclude other sleep and medical disorders, including narcolepsy, which often mimics delayed sleep phase disorder.
Sleep diaries are often used together with a wrist watch-like device (called an actigraph) that records sleep and wake activity over the course of days to weeks. Sometimes overnight and daytime sleep studies may be required. Sleep studies are tailored to address the sleep pattern of the individual. For example, an ‘overnight’ sleep study might be performed during the day in a shift worker. Measuring body temperature and melatonin levels are other useful tests.
Management and Treatment
How are circadian rhythm sleep disorders treated?
Treatment options for circadian rhythm sleep disorders vary based on the type of disorder and the degree to which it affects your quality of life. Your healthcare provider will develop a personalized treatment plan, which improves your chance of success. Most treatment plans require a combination of approaches.
Treatment options include:
Lifestyle and behavior therapy: This approach encourages changes to improve sleep and to develop good sleep habits. Good sleep habits include maintaining regular sleep-wake times (even on weekends and vacations); avoiding naps (exception: shift workers); developing a regular routine of exercise (avoid high-intensity exercise within one hour of bedtime); and avoiding alcohol, caffeine, nicotine, and stimulating activities within several hours of bedtime.
Bright light therapy: Bright light therapy is used to advance or delay sleep. The timing of this treatment is critical and requires guidance from a sleep specialist. Bright light therapy works by resetting the circadian clock to be more in sync with the earth’s cycle of light and dark. A high intensity light (2,000 to 9,500 lux) is required and the duration and timing of exposure varies from one to two hours.
Exposure to bright light in the morning may help you if you have a delayed sleep disorder. You should also decrease your exposure to light in the evening and during the night by reducing indoor lighting and avoiding bright TV and computer screens. Exposure to bright light in the evening may help if you have advanced sleep disorder.
Medications: Medications such as melatonin (available over-the-counter), wake-promoting agents (such as modafinil [Provigil®]) or caffeine, and short-term sleep aids may be used to adjust and maintain the sleep-wake cycle to the desired schedule. Tasimelteon (Hetlioz®) is approved to treat non-24-hour sleep-wake disorder.
Chronotherapy: This therapy approach uses progressive advancement or delay (three hours every two days) of sleep time depending on the type and the severity of the disorder. This type of therapy requires a firm commitment by you and your partner, as it can take weeks to successfully shift the sleep-wake cycle. Once the desired schedule is achieved, you have to keep this regular sleep-wake schedule.
Outlook / Prognosis
Circadian rhythm sleep disorders are caused by continuous or occasional disruption of sleep patterns. There are many types of circadian rhythm sleep disorders. Each has its own features. Treatments are based on the type of sleep disorder you have and the degree to which it affects the quality of your life. Never hesitate to contact your healthcare provider if you experience any changes in your sleep pattern or have any questions about your treatment or other treatment options.