The key role of insomnia and sleep loss in the dysregulation of multiple systems involved in mood disorders: A proposed model

Abstract

Summary Mood disorders are amongst the most prevalent and severe disorders worldwide, with a tendency to be recurrent and disabling. Although multiple mechanisms have been hypothesized to be involved in their pathogenesis, just a few integrative theoretical frameworks have been proposed and have yet to integrate comprehensively all available findings. As such, a comprehensive framework would be quite useful from a clinical and therapeutic point of view in order to identify elements to evaluate and target in the clinical practice. Because conditions of sleep loss, which include reduced sleep duration and insomnia, are constant alterations in mood disorders, the aim of this paper was to review the literature on their potential role in the pathogenesis of mood disorders and to propose a novel theoretical model. According to this hypothesis, sleep should be considered the main regulator of several systems and processes whose dysregulation is involved in the pathogenesis of mood disorders. The model may help explain why sleep disturbances are so strikingly linked to mood disorders, and underscores the need to evaluate, assess and target sleep disturbances in clinical practice, as a priority, in order to prevent and treat mood disorders.

Sleep deprivation and stress: a reciprocal relationship

“…Despite extensive research since the discovery of the fundamental importance of sleep, its functions and functioning are still a matter of debate. However, a consensus exists regarding the cardinal contributions of sleep to mental and physical health with a multitude of studies pointing out the adverse consequences of disturbed sleep [182][183][184][185]. The high prevalence of insomnia and poor sleep quality in modern societies highlights the need for further and better research aiming at unveiling the mechanisms behind sleep regulation and function [186].…”

Expert Opinions and Consensus Recommendations for the Evaluation and Management of Insomnia in Clinical Practice: Joint Statements of Five Italian Scientific Societies

“…Although insomnia can be a symptom or an independent disorder, it is most frequently observed as a comorbid condition. It may precipitate, exacerbate, or prolong a broad range of comorbid conditions including mental and physical illnesses (16)(17)(18)(19)(20)(21)(22). In particular, 40-50% of subjects with insomnia also present a comorbid mental disorder (12), and in this framework, insomnia may impair the trajectory of the disorder being related to its severity, relapses and recurrences, and suicidality (23)(24)(25).…”

Insomnia Might Influence the Thickness of Choroid, Retinal Nerve Fiber and Inner Plexiform Layer

“…According to our hypothesis, insomnia might be a potential confounder factor for the OCT findings in patients with major psychiatric disorders. A growing body of evidence demonstrates that sleep and circadian rhythm disruptions are associated with the pathophysiology of psychiatric [17] and neurodegenerative disorders [18,19]. Recent Genome-wide association analysis identified 57 loci associated with insomnia symptoms and asserted the evidence of shared genetic factors between insomnia and cardio-metabolic, behavioral, psychiatric, and reproductive traits [20].…”