Circadian Rhythm Disorders

Your Body Clock

Circadian processes refer to biological activities that occur “around the day”, on a 24-hour cycle. The oldest and most powerful circadian process is our relationship to light and dark, or wake and sleep.

All plants and animals (including flies) demonstrate changes in behavior associated with light and dark which we call “circadian rhythms.” In the brain, a small region known as the suprachiasmatic nucleus (SCN) is responsible for maintaining our circadian rhythms using cues from daylight and darkness. SCN activity varies from person to person and accounts for why some of us are “night owls” and others “morning larks.” These traits are genetic and can be seen in families.

Disorders of the circadian rhythm system can result from decreased light activation of the SCN, irregular SCN rhythms, or environmental influences that cause an irregular sleep and wake pattern.

Signs & Symptoms

Children, adolescents, and adults of all ages may suffer from circadian rhythm disorders (CRDs). The most common symptoms result from a mismatch of the time of day with the internal SCN rhythm. This can lead to excessive daytime sleepiness and insomnia at night. Adolescents, in particular, often demonstrate these behaviors due to the normal development of their circadian rhythm system. Children at this stage of maturation show a delay in their internal clock for sleep, and as a result, wake up later. Older adults also demonstrate maturational changes, resulting in an advance in their circadian rhythm. This is noted as an early wake-up time and early bedtime.

Circadian Rhythm Diagnoses

There are several recognized CRDs and they include the following:

  • Jet Lag or Rapid Time Zone Change Syndrome
  • Shift Work Sleep Disorder
  • Delayed Sleep Phase Syndrome
  • Advanced Sleep Phase Syndrome
  • Non 24-Hour Sleep Wake Disorder
  • Irregular Sleep Wake Pattern Disorder

Diagnoses often require specialized tools such as sleep and wake diaries, actigraphy, and laboratory testing. Since CRDs often co-exist with other sleep and wake disorders, a proper diagnosis requires an understanding of the underlying neurological systems. Our expertise in neuroscience and sleep medicine provides our patients accurate diagnoses and successful therapy.

Treatment for Circadian Rhythm Disorders

There are many strategies for treating specific CRDs and managing the symptoms. Behavioral therapies, bright light therapy, and medical interventions, all play a part in treating CRDs. In addition, we provide a coordinated approach for treating other sleep and wake disorders associated with CRDs in children, adolescents, and adults of all ages.