What Is a Circadian Rhythm Sleep Disorder?

Circadian rhythm sleep disorders, also known as sleep-wake cycle disorders, occur when there is a mismatch between your internal circadian rhythm and your external environment, which can make it hard for you to get adequate, restful sleep.

Your circadian rhythm is a daily cycle of mental, physical, and behavioral processes in your body. Also known as your body clock, it governs bodily processes such as sleep, heart rate, blood pressure, body temperature, digestion, and hormone production, among others.

Each circadian rhythm cycle lasts anywhere between 23.5 to 24.5 hours or approximately the length of one day. This is because the circadian rhythm is largely tuned to the presence of light.

This article discusses the types, causes, symptoms, diagnosis, and treatment of circadian rhythm sleep disorders. We also explore the mental health impact of these sleep disorders and some coping strategies that may be helpful.

Types of Circadian Rhythm Sleep Disorders

These are some of the types of circadian rhythm sleep disorders:

• Shift work disorder: Shift work disorder affects people who work shifts outside the 8:00 a.m. to 6:00 p.m. window. This schedule tend to clash with the body’s natural circadian rhythm and can affect your ability to sleep well during the day. It can also make it hard for you to stay awake during your night shift.
• Delayed sleep-wake phase disorder (DSWPD): One of the most common circadian rhythm disorders, this condition can cause you to sleep later than most people and have difficulty waking up in the morning. It can make it hard for you to function at school or work and leave you feeling tired and irritable during the day.
• Advanced sleep-wake phase disorder (ASWPD): This condition can make it hard for you to stay awake in the evening and cause you to wake up very early in the morning. It can affect your work, school, and social activities.
• Irregular sleep-wake rhythm disorder (ISWRD): Instead of an uninterrupted night’s sleep, sleep is fragmented into several periods during the 24-hour day. Irregular sleep-wake rhythm disorder can cause you to experience several short periods of sleep and wakefulness. You may not feel rested during the day and have to take several naps due to excessive sleepiness.
• Non–24-hour sleep-wake rhythm disorder: This condition occurs when your circadian rhythm is not in tune with the 24-hour day. It typically affects people who are blind and have limited exposure to light. It can cause your sleep timings to gradually become more delayed so that sleep time will drift into the daytime.
• Jet lag disorder: Jet lag is a temporary sleep disorder you may experience if you travel rapidly across multiple time zones, due to the time difference. It can take your body a few days or longer to adjust to the timings of your new location. In the meantime, you might find yourself awake or asleep at odd hours of the day.

Symptoms of Circadian Rhythm Sleep Disorders

The symptoms you experience can vary depending on the type of circadian rhythm sleep disorder you have and may include:

• Difficulty staying awake when you need to be active
• Difficulty falling asleep when you go to bed
• Daytime sleepiness
• Tiredness and exhaustion
• Lethargy
• Headaches and other pains
• Upset stomach

Mental Health Impact of Sleep Disorders

Circadian rhythm sleep disorders can also affect your mental health and cause you to experience symptoms such as:

• Difficulty concentrating
• Lack of alertness
• Impaired learning and memory
• Poor judgment and risky behaviors
• Difficulty regulating mood
• Relationship difficulties

In addition to these symptoms, circadian rhythm sleep disorders are associated with several mental health conditions, including:

• Major depressive disorder
• Bipolar disorder
• Post-traumatic stress disorder
• Anxiety disorders
• Schizophrenia
  

Causes of Circadian Rhythm Sleep Disorders

These are some of the factors that can raise your risk for the development of circadian rhythm sleep disorders:

• Age: Your circadian rhythms can fluctuate with age. For instance, teenagers tend to have a later bedtime than most people and have an increased risk of delayed sleep-wake phase disorder. Similarly, older adults tend to sleep and wake up earlier than most people, putting them at risk for advanced sleep-wake phase disorder. Older adults are also at greater risk of experiencing jet lag and shift work disorder.
• Gender: Men or people who were assigned male at birth are at greater risk of developing advanced sleep-wake phase disorder. Women or people who were assigned female at birth are at greater risk of developing circadian rhythm sleep disorders during pregnancy, menopause, or the postpartum period.
• Occupation: People who work in fields such as medicine and security, and have shifts outside the traditional 9:00 a.m. to 5 p.m. workday may be at greater risk of developing shift work disorder. Jet lag disorder is more common among pilots, flight attendants, and people who travel often for business.
• Genetics: Inheriting variations in genes that control your circadian rhythm, known as circadian clock genes, can raise your risk of developing circadian rhythm sleep disorders.
• Medical conditions: Medical conditions such as Parkinson’s disease, Alzheimer’s disease, Huntington’s disease, Angelman syndrome, autism, blindness, stroke, and brain tumors are linked to an increased risk of circadian rhythm sleep disorders.
• Mental health conditions: There is a bi-directional relationship between sleep disorders and mental health conditions such as depression, anxiety, bipolar disorder, and schizophrenia.
• Substance use: Chronically using caffeine, alcohol, nicotine, or illegal drugs can raise your risk of circadian rhythm sleep disorders. 

Diagnosing Circadian Rhythm Sleep Disorders

Your healthcare provider may refer you to a sleep specialist for diagnosis and treatment of a circadian rhythm sleep disorder. 

Diagnosing a circadian rhythm sleep disorder may involve the following steps:

• Medical history: Your healthcare provider will inquire about your personal and family medical history. 
• Clinical interview: Your healthcare provider may ask you what symptoms you’re experiencing and how long you’ve had them. They may also inquire about your work, lifestyle, and use of substances.
• Physical exam: Your healthcare provider may perform a physical exam to help rule out medical conditions that might contribute to sleep problems, including heart disease, lung conditions, or airway problems.
• Actigraphy: Your healthcare provider may ask you to wear a small motion sensor for a few days or weeks to measure your sleep-wake cycles.
• Sleep study: Your healthcare provider may recommend a sleep study, to monitor your breathing, heart rate, brain waves, oxygen levels, eye and leg movements, and other parameters while you’re sleeping.
• Other tests: Your doctor may also perform other tests to check your natural sleep patterns, your body temperature, your blood chemistries, and the levels of hormones like melatonin and cortisol in your blood or saliva.

Circadian Rhythm Sleep Disorder Treatment

Treatment options for a circadian rhythm sleep disorder may include:

• Light therapy: Exposure to bright light, similar to sunlight, can help reset your circadian rhythm. For instance, light therapy in the morning may move your sleep and wake times earlier and can help reduce daytime sleepiness; whereas, light therapy in the afternoon or early evening can help you to move your sleep and wake times later.
• Medication: Medications like benzodiazepines and zolpidem can help you fall asleep at the desired time and sleep for longer. They are generally recommended for short-term use. On the other hand, medications like modafinil and armodafinil can help you stay awake and alert when you need to be active.
• Supplements: Melatonin supplements can help induce sleep, and may be recommended to be taken a few hours before your desired sleep time.
• Lifestyle changes: Your healthcare provider may recommend avoiding caffeine, alcohol, nicotine, and certain medications in the evening.
• Sleep hygiene: It can be helpful to practice good sleep hygiene habits. Avoid using electronic screens before bedtime and sleep in a cool, dark, and quiet environment.
• Healthy routine: Try to get some physical activity every day, maintain a consistent bedtime, and stick to fixed meal timings.

Coping With a Circadian Rhythm Sleep Disorder

These are some strategies that can help you cope with a circadian rhythm sleep disorder:

• Learn about the condition: Educating yourself about the condition can help you understand what you’re experiencing, why it’s happening, what to expect, and how you can cope with it.
• Ask loved ones for help: Tell loved ones how you’re feeling and let them help you. This may involve picking you up from work after a night shift so you’re not driving when you’re exhausted, letting you sleep undisturbed during the daytime so you get adequate rest, or making other accommodations around your disorder.
• Seek support: You can join a support group of people with similar conditions and circumstances for inspiration, advice, and resources. If you feel like you’re unable to cope, it may be helpful to visit a mental healthcare provider.