Circadian misalignment in mood disturbances

Curr Psychiatry Rep. 2009 Dec;11(6):459-65. doi: 10.1007/s11920-009-0070-5.


Recent refinements in methodology allow chronobiological researchers to answer the following questions: is there circadian misalignment in sleep and mood disturbances, and, if so, is it of the phase-advance or phase-delay type? Measurement of the dim light melatonin onset-to-midsleep interval, or phase-angle difference, in sleep and mood disorders should answer these questions. Although the phase-advance hypothesis of affective disorders was formulated three decades ago, recent studies suggest that many, if not all, mood disturbances have a circadian misalignment component of the phase-delay type, operationally defined as a delay in the dim light melatonin onset relative to the sleep/wake cycle. Phase-delayed disorders can be treated with bright light in the morning and/or low-dose melatonin in the afternoon/evening. Phase-advanced disorders can be treated with bright light in the evening and/or low-dose melatonin in the morning.

Publication types

  • Review

MeSH terms

  • Circadian Rhythm*
  • Humans
  • Melatonin / therapeutic use
  • Mood Disorders / therapy*
  • Phototherapy*
  • Sleep
  • Time Factors


  • Melatonin