Behaviorally and environmentally induced non-24-hour sleep-wake rhythm disorder in sighted patients

J Clin Sleep Med. 2022 Feb 1;18(2):453-459. doi: 10.5664/jcsm.9612.


Study objectives: To determine whether there was evidence of circadian or sleep-regulatory dysfunction in sighted individuals with non-24-hour sleep-wake rhythm disorder.

Methods: Three sighted individuals with signs and/or symptoms of non-24-hour sleep-wake rhythm disorder were studied. Thirty-five- to 332-day laboratory and home-based assessments of sleep-wake and circadian timing, endogenous circadian period, photic input to the circadian pacemaker, and/or circadian and sleep-wake-dependent regulation of sleep were conducted.

Results: No evidence of circadian dysfunction was found in these individuals. Instead, sleep-wake timing appeared to dissociate from the circadian timing system, and/or self-selected sleep-wake and associated light/dark timing shifted the circadian pacemaker later, rather than the circadian pacemaker determining sleep-wake timing.

Conclusions: These findings suggest that the etiology of this disorder may be light- and/or behaviorally induced in some sighted people, which has implications for the successful treatment of this disorder.

Citation: Emens JS, St Hilaire MA, Klerman EB, et al. Behaviorally and environmentally induced non-24-hour sleep-wake rhythm disorder in sighted patients. J Clin Sleep Med. 2022;18(2):453-459.

Keywords: circadian rhythm; circadian rhythm sleep disorders; light; melatonin; non–24-hour sleep-wake rhythm disorder.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Circadian Rhythm / physiology
  • Humans
  • Melatonin*
  • Sleep
  • Sleep Disorders, Circadian Rhythm* / complications
  • Sleep Disorders, Circadian Rhythm* / therapy
  • Sleep Wake Disorders* / diagnosis


  • Melatonin