Non-24-Hour Sleep-Wake Disorder

What is Non-24-Hour Sleep-Wake Disorder (Non-24)?

Non-24-Hour Sleep-Wake Disorder (Non-24) is a circadian rhythm disorder in which the primary symptom is recurrent misalignment between a person’s internal body clock and the daily 24-hour cycle caused by environmental light-dark cues. Non-24 can affect total and/or partial sleep disruption, leading to chronic cycles of sleep deprivation and disrupted alertness. Non-24 is a disabling yet rarely recognized disorder.

What are the Symptoms of Non-24?

People with Non-24 may experience a wide variety of symptoms including:

  • Daytime sleepiness or fatigue
  • Trouble falling or staying asleep at night
  • Insomnia
  • Lack of or impaired concentration, attention, or memory
  • Mood changes such as irritability, anxiety, or depression
  • Other physical or cognitive changes

What Causes Non-24?

The cause of Non-24 is not fully understood, and there is no “cure,” but it could be related to changes in one’s environment or genetics. Most people with Non-24 may have difficulty synchronizing and maintaining their internal body clock to environmental cues, such as sunlight, meal timing, and daily routines.

How is Non-24 Diagnosed?

Non-24 is often not discussed or included in discussions and evaluations of sleep disturbances which can lead to a delayed or missed diagnosis. Non-24 is typically diagnosed and managed with a comprehensive evaluation by a physician experienced in diagnosing and treating circadian rhythm disorders. Diagnostic techniques can include a detailed sleep history, actigraphy, and polysomnography.

What Treatments are Available for Non-24?

Treatment for Non-24 typically involves resetting the internal body clock to be in sync with the 24-hour light-dark cycle, as well as making changes to one’s environment and lifestyle. Treatment approaches may include pharmacological treatments to reduce symptoms of sleep disturbance when needed, and may involve implementing strategies to minimize alertness and awakenings in both the morning and night.