Allison Harvey has published an important article in the 2011 edition of Annual Review of Clinical Psychology titled “Sleep and circadian functioning: Critical mechanisms in the mood disorders.” She identifies seven lines of research which bear on the relationship between sleep and mood disorders:
- sleep disturbance is a risk factor and early warning signal of an episode
- sleep disturbance contributes to relapse and mood improvement
- sleep is critical for affect regulation
- sleep is important for cognitive functioning
- sleep impacts obesity
- sleep deprivation is associated with substance use
- sleep deprivation contributes to suicidality
She then reviews literature at the behavioral, social, cognitive, and neuro-biological levels to explore further the relationship between sleep and mood, leading her to the conclusion that sleep disturbance is “… an important but under-recognized mechanism in the multifactorial cause and maintenance of the mood disorders (p. 297).” The intimate interlinking between these levels creates many opportunities for vicious cycles that lead to relapse and worsening of symptoms and for virtuous cycles that lead to improved quality of life and guide treatment interventions.
Because sleep biology is an open system and is easily influenced by exogenous factors, powerful and inexpensive behavioral treatments have evolved to improve sleep quality. Cognitive behavior therapy for insomnia, light/dark therapy, and sleep deprivation are identified as particularly promising interventions in this article. These interventions can easily be interwoven into the treatment plan for mood disorders.