Sleep, Sleep Disorders, and Mental Health: A Narrative Review

Evidence suggests that sleep is a vital component of physical and health well-being. However, while sleep problems are present in individuals with mental health problems such as depression, it has not been clear whether these conditions are independent or whether they might be causally related. Indeed, if sleep or sleep disorders predispose or modify onset and outcomes of mental health issues, treatment of these factors could be explored as new mental health prevention or treatment options. The aim of this review was to examine in detail the bidirectional relationship between sleep, sleep disorders, and mental and physical health and well-being. It has considered the evidence that sleep architecture disruption, occurring through both quantity, quality, and timing of sleep as well as through the presence of sleep disorders may both influence mental health and well-being as well as be disrupted by both physical and mental health conditions. Also, the review has explored the effects of sleep disruption on mental health and performance through fatigue, mood, and vigilance. The review has considered the bidirectionality between sleep, sleep disorders, and mental health to examine how these may lead to or exacerbate mental health disorders such as affective, anxiety, autism, depressive and schizophrenia disorders but also considers how these conditions can affect sleep. The review highlights that poor sleep or the presence of a sleep disorder can increase the risks from mental health conditions such as suicidality. Furthermore, mental health conditions such as anxiety and worry can cause racing or repetitive thoughts that can keep an individual awake, leading to shortened sleep. It is important that sleep and sleep disorders are considered potential modifiable factors that could improve mental health outcomes. The important interconnect between both physical and mental health and sleep, in patient evaluations, also needs to be considered as these may affect treatment pathways and patient outcomes. Further, more robust and perspective research is required to establish the triad relationship of physical, mental health, and sleep.