By: Joshua Roland, MD, FAASM

It is fairly intuitive that mood and sleep have a bidirectional relationship.  When we sleep poorly, we are more likely to not be in our best disposition and have a compromised emotional threshold the following day.  We also know anxiety, stress, and depression can contribute to having a more difficult time sleeping.  The literature has by in large supported this, and it is not a huge surprise that more data is coming out validating and defining the relationship between sleep and mood [1, 2].

Lately, reports suggest that irregularity of sleep schedule may be a potentially prominent piece in this puzzle [3].  In a study recently conducted at the University of Michigan, an irregular sleep/wake schedule demonstrated a detrimental impact on mood and worsening of PHQ-9 scores, a common measure of depression, in the setting of first-year medical residents [4].  While this may not be an especially earth-shattering revelation, and this population may be unique in the psychological and logistical challenges they face, the concept the study highlights is very relevant at present.  We know that sleep irregularities, along with depression and anxiety, have been on the rise during the global COVID-19 pandemic [5, 6].  Unemployment, increase in asynchronous work schedules, declining sleep hygiene, and loss of routine social interactions, along with other contributors of circadian entrainment, have all resulted in a more scattered and less routine sleep schedule for many.  While there is always concern regarding association vs. causation in observational studies (are people depressed because of irregularity in their schedule, or is their schedule irregular because they are depressed), the overall concept is a potentially intriguing area to target as part of treatment plans.

The complex bidirectional anxiety/depression and insomnia loop can be at times challenging to break.  To truly address all the contributors to insomnia and mood disorders often requires a great deal of time, expertise, and logistical solutions.  Sleep schedule irregularity, on the other hand, can be fairly easy to at least improve through basic components of sleep hygiene/CBT-i, circadian rhythm therapies when applicable, and a bit of patient discipline [7, 8].  The simple act of setting a consistent morning alarm every day, along with helping patients appreciate how a laissez-faire approach to sleep schedule can be detrimental, can sometimes go a long way towards reestablishing regularity.  Many aspects of life can seem out of our control these days.  It can be helpful for patients to understand that sleep schedule is something they have the ability to have control over.

While more studies are needed defining the relationship, exploring etiological mechanisms, and evaluating if correction of schedule irregularity significantly impacts mental health, striving for a consistent sleep/wake schedule may potentially be low hanging fruit as we work towards trying to renormalize and combat the sleep and mood disturbances that the pandemic has exacerbated.


  1. Baglioni, C., et al., Sleep and mental disorders: A meta-analysis of polysomnographic research. Psychol Bull, 2016. 142(9): p. 969-990.
  2. Palagini, L., et al., The key role of insomnia and sleep loss in the dysregulation of multiple systems involved in mood disorders: A proposed model. J Sleep Res, 2019. 28(6): p. e12841.
  3. Chaput, J.P., et al., Sleep timing, sleep consistency, and health in adults: a systematic review. Appl Physiol Nutr Metab, 2020. 45(10 (Suppl. 2)): p. S232-S247.
  4. Fang, Y., et al., Day-to-day variability in sleep parameters and depression risk: a prospective cohort study of training physicians. NPJ Digit Med, 2021. 4(1): p. 28.
  5. Jahrami, H., et al., Sleep problems during the COVID-19 pandemic by population: a systematic review and meta-analysis. J Clin Sleep Med, 2021. 17(2): p. 299-313.
  6. Xiong, J., et al., Impact of COVID-19 pandemic on mental health in the general population: A systematic review. J Affect Disord, 2020. 277: p. 55-64.
  7. Suh, S., et al., Clinical significance of night-to-night sleep variability in insomnia. Sleep Med, 2012. 13(5): p. 469-75.
  8. Abbott, S.M., K.J. Reid, and P.C. Zee, Circadian Rhythm Sleep-Wake Disorders. Psychiatr Clin North Am, 2015. 38(4): p. 805-23.