Circadian Rhythm Disorders

Circadian rhythm disruptions become disorders when they affect daily life, cause distress, or impair function. 

Delayed Sleep-Wake Phase Disorder
The normal sleep interval is pushed back two or three hours, so you don’t feel tired until after midnight and prefer to sleep until mid-morning. A shift in this direction is normal among teenagers, but usually resolves on its own over time.

Advanced Sleep-Wake Phase Disorder
The normal sleep interval is moved up two or three hours, so you prefer to fall asleep in the very early evening and wake up in the early morning hours. A shift in this direction is normal among older adults, but not to this extreme.

Non-24-Hour Sleep-Wake Syndrome
This is common in people who are blind and cannot perceive light. The normal daily circadian clock is extended two or three hours. Instead of wanting to sleep every 24 hours, you may not be ready to sleep until 25 or 26 hours after your previous sleep onset. As a result, sleep and wake times change daily.

Irregular Sleep-Wake Rhythm
This is common in people with neurological conditions like dementia or people who have had a traumatic brain injury. Sleep intervals are short (perhaps two to three hours long) and spread throughout the day.

Your sleep specialist will begin by asking questions about your sleep preferences and family history, since circadian rhythm disorders can run in families. To learn more about your habits, they may recommend that you keep a sleep log for several weeks. You may also be asked to wear an actigraphy monitor -- a watch-like device that records activity, light exposure, sleep, and wake times.

Chronotherapy
This hallmark treatment for circadian rhythm disorders uses light therapy and/or melatonin -- a natural hormone your body makes to help induce sleep -- to affect the body’s natural circadian rhythm. You may need just one or both and may need to use them periodically or for life.

• Bright Light Therapy: Exposure to bright lights tells your brain that it should be awake. Bright light therapy helps train your brain to shift your normal sleep patterns. Your doctor will specify when and for how long to use bright light therapy. For example, if you have advanced sleep-wake phase disorder, you may use light therapy daily from 5:00-6:00 pm, when you normally struggle to stay awake. If you have delayed sleep-wake phase disorder, you may use light therapy daily from 8:00-8:30 am to feel more alert.
• Melatonin: Melatonin is often used in people with delayed sleep-wake phase disorder. Taking low doses a few hours before your goal bedtime helps acclimate your body to sleep and shape your sleep phase into a more normal pattern.

Medications
Certain prescription medications may be appropriate to treat extreme cases of circadian rhythm disorders.