Circadian rhythm sleep disorders (CSDRs)

Circadian rhythm sleep disorders (CSDRs) are defined as disturbances in the sleep pattern caused either by an change in the endogenous circadian timing system or a misalignment between the endogenous circadian system and the 24-hour social and physical environment (1).

According to the second International Classification of Sleep Disorders the general criteria for CRSD are as follows

• 1. persistent or recurrent pattern of sleep disturbance that is thought to be primarily due to either alteration in the circadian timing system or a misalignment between endogenous circadian rhythms and external factors that affect the timing of sleep
• 2. sleep disturbance that leads to insomnia, excessive sleepiness, or both;
• 3. sleep disturbance that is associated with impairment of function (2)

CSRDs can be divided into

• timing of sleep and wakefulness altered by exogenous factors
  • shift work disorder (SWD)
  • jet lag disorder (JLD)
• timing of sleep and wakefulness altered by endogenous circadian clock
  • advanced sleep phase disorder (ASPD)
  • delayed sleep phase disorder (DSPD)
  • free-running disorder (FRD)
  • irregular sleep-wake rhythm disorder (ISWR) (3)

CSRDs should be taken into account in the differential diagnosis in a patient presenting with symptoms of insomnia and/or hypersomnia (2).

Since both behavioural and environmental factors play an important role in the development and maintenance of the disease, management strategies should include a multimodal treatment approach of behavioral and/or pharmacologic approaches (2)

Reference:

• 1. Barion A, Zee PC. A clinical approach to circardian rhythm sleep disorders. Sleep Med. 2007;8(6):566-577
• 2. Lu BS, Zee PC. Circadian Rhythm Sleep Disorders. Chest 2006;130(6):1915-1923
• 3. Morgenthaler TI et al. Practice Parameters for the Clinical Evaluation and Treatment of Circadian Rhythm Sleep Disorders - An American Academy of Sleep Medicine Report. Sleep. 2007;30(11):1445-1459