The associations between sleep/rhythms and psychiatric disorders are not well understood. With additional research we can better address key issues and improve patient outcomes.
There is overwhelming evidence that sleep and circadian rhythm disturbances and disorders are prevalent in psychiatric patients and associated with worse outcomes. Nonetheless, the associations between sleep/rhythms and psychiatric disorders are not well understood, and additional research is necessary to mechanistically link sleep dysfunction to mental illness. Furthermore, despite the fact that there is evidence that treating sleep and behavioral rhythms improves psychiatric outcomes, training in sleep medicine for psychiatrists is often insufficient. As a result, sleep and rhythms are often not adequately assessed or appropriately targeted in the clinical practice of psychiatry.
The articles in this Special Report address key issues. While the association between insomnia and psychiatric disorders has long been recognized, more recent evidence demonstrated a strong relationship between insomnia and suicidal ideation and behaviors across the lifespan, as discussed by Wilfred R. Pigeon, PhD, and Todd M. Bishop, PhD. Thus, patients with insomnia, even in the absence of severe psychiatric symptomatology, should be screened for suicide, and treatment for insomnia should be considered to reduce suicidal ideation.
Circadian rhythm abnormalities are also prevalent in psychiatric patients, although they have received less attention than sleep problems. Practitioners may not always recognize circadian abnormalities in their patients and may lack the training and knowledge to provide adequate chronotherapy; for example, delayed onset due to a shifted circadian rhythm may be mistaken for sleep onset insomnia if a careful sleep history is not obtained. Helen J. Burgess, PhD, and Leslie M. Swanson, PhD, discuss the association between delayed sleep phase and mood, anxiety and substance abuse, as well as the increased risk of psychiatric illness related to irregular sleep timing. Their expert tips and guidance in screening patients for circadian rhythm abnormalities as well as stabilizing and entraining rhythms with light therapy, melatonin, and behavioral interventions is most useful.
Similarly, the article by Ellen E. Lee, MD, discusses how sleep can affect psychiatric disorders by increasing inflammation and oxidative stress. Her group has shown that patients with serious mental illnesses have increased levels of pro-inflammatory cytokines. Other studies have shown that sleep deprivation, insomnia, and obstructive sleep apnea are not only more common in patients with psychiatric disorders, but they are also associated with worse outcomes and contribute to inflammation. Conversely, treatments for insomnia and sleep apnea have been shown to have positive effects on psychiatric symptomatology. Taken together, these findings suggest mechanistic pathways by which sleep disorders, inflammation, and psychiatric illness are linked.
In summary, there is increasing evidence that disturbed sleep and circadian rhythms impact the risk for developing psychiatric disorders, and inflammatory processes are suggested as one possible mechanism of this well-established relationship. Sleep and circadian rhythm disturbances are modifiable factors, and while data on the effects of sleep disorder treatment on inflammatory processes is preliminary and limited, treating sleep and behavioral activity rhythms have consistently shown positive impact on mental health outcomes. Most importantly, treatment of sleep dysfunction may reduce suicide risk.
Future research is necessary to better understand the mechanistic pathways and to improve the availability of evidence-based treatments of sleep disorders in patients with mental health disturbances. Hopefully this Special Report will help you better understand some of these relationships and will lead to improved patient outcomes.
Dr Benca is Chair of Psychiatry & Human Behavior in the School of Medicine at University of California, Irvine. She reports that she has served as a consultant to Eisai, Genomind, Jazz, and Merck.