Circadian Rhythm Sleep-Wake Disorders

Circadian Rhythm Sleep-Wake Disorders all involve a problem in the timing of when an individual sleeps and is awake. The human body has a master circadian clock in a control centre of the brain known as the suprachiasmatic nucleus (SCN).

Criterion A

A persistent or recurrent pattern of sleep disruption that is primarily due to an alteration of the circadian system or to a misalignment between the endogenous circadian rhythm and the sleep-wake schedule required by an individual’s physical environment or social or professional schedule.

Criterion B

The sleep disruption leads to excessive sleepiness or insomnia, or both.

Criterion C

The sleep disturbance causes clinically significant distress or impairment in social, occupational, and other important areas of functioning.

A pattern of delayed sleep onset and awakening times, with an inability to fall asleep and awaken at a desired or convention ally acceptable earlier time.

  • Familial: A family history of delayed sleep phase is present.
  • Overlapping with non-24-hour sleep-wake type: Delayed sleep phase type may overlap with another circadian rhythm sleep-wake disorder, non-24-hour sleep-wake type.

A pattern of advanced sleep onset and awakening times, with an inability to remain awake or asleep until the desired or conventionally acceptable later sleep or wake times.

  • Familial: A family history of advanced sleep phase is present.

A temporally disorganized sleep-wake pattern, such that the timing of sleep and wake periods is variable throughout the 24- hour period.

A pattern of sleep-wake cycles that is not synchronized to the 24-hour environment, with a consistent daily drift (usually to later and later times) of sleep onset and wake times.

Insomnia during the major sleep period and/or excessive sleepiness (including inadvertent sleep) during the major awake period associated with a shift work schedule (i.e., requiring unconventional work hours).

Severity Specifier

Specify if:

  • Episodic: Symptoms last at least 1 month but less than 3 months.
  • Persistent: Symptoms last 3 months or longer.
  • Recurrent: Two or more episodes occur within the space of 1 year.

While light therapy and melatonin can help, it is more effective and ethical to lobby for developmentally appropriate polices for school hours.