Non-24-hour sleep-wake disorder
Non-24-hour sleep-wake disorder
How Non-24 causes drifting sleep times, especially in blind patients, and how circadian treatment is timed.
A circadian rhythm that does not stay aligned to 24 hours
Non-24-hour sleep-wake disorder occurs when the internal circadian clock repeatedly drifts later—or occasionally earlier—relative to the environmental day. Sleep and wake times cycle in and out of alignment, producing alternating periods of insomnia and daytime sleepiness. It is most common in totally blind people who lack light input to the circadian system, but rare sighted cases occur.
Diagnosis requires a pattern over time
Progressive drift
Sleep onset and wake time shift across days or weeks.
Cyclic symptoms
Function improves temporarily when the internal rhythm aligns with obligations.
Objective records
Sleep diaries and actigraphy help distinguish drift from inconsistent habits.
Vision history
Degree of light perception strongly affects likelihood and management.
Treatment principles
- Precisely timed melatonin or approved circadian medication when appropriate
- Scheduled light exposure for selected sighted patients
- Regular wake, meal and activity cues
- Avoid mistimed light or supplements that shift the clock in the wrong direction
- Track the rhythm so treatment is timed to circadian phase
- Address coexisting sleep apnea, depression or medication effects
Why self-treatment can fail
Melatonin timing can shift the circadian clock in opposite directions depending on when it is taken. Dose and timing should be selected deliberately; simply taking a large dose at bedtime may not entrain the rhythm and can worsen daytime sedation.
How W8MD can help
W8MD Weight Loss, Sleep & MedSpa provides physician-supervised care from active offices in Brooklyn, New York and Northeast Philadelphia, serving patients from greater New York City, New Jersey and the greater Philadelphia region. Telehealth may be available when clinically and legally appropriate.
W8MD accepts many insurance plans for visits. When a plan covers an FDA-approved medication and the patient meets its criteria, W8MD can submit prior-authorization documentation. The insurer determines coverage and approval.
W8MD can review longitudinal sleep timing, visual status, work requirements and medications and coordinate actigraphy or circadian treatment. Persistent drowsy driving requires immediate safety precautions.
W8MD regional resources: Visit NYC Medical Weight Loss and Philadelphia Medical Weight Loss. For encyclopedia background, see obesity and weight loss at WikiMD.
Frequently asked questions
Is Non-24 the same as delayed sleep phase?
No. Delayed sleep phase is stably late; Non-24 continues to drift.
Can sighted people have it?
Rarely, after other causes of irregular sleep are excluded.
Will sleeping pills correct the clock?
Sedation does not necessarily entrain the circadian rhythm.
Evidence and authoritative sources
Request a sleep medicine consultation
W8MD Weight Loss, Sleep & MedSpa provides physician-supervised care in Brooklyn, New York and Northeast Philadelphia. Telehealth may be available for eligible patients based on location and applicable requirements.
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