Sleep and Circadian Disruption in Depression and Anxiety Disorders: An Inflammatory Insight

Sleep and circadian rhythm are reciprocally interlinked with mental health. Disturbed sleep or insufficient sleep activates and propagates inflammatory pathways. Sleep deprivation alone can stimulate the toll-like receptor (TLR) pathway and induce cytokine production. Inflammatory markers act under circadian rhythms and fluctuations in blood levels are seen; interestingly, these fluctuations depend on a particular time of the day. In addition to immunosuppression, major depression relates to inflammatory activation. Major depressive disorder (MDD) is distinguished by the activation of T cell with increased T helper (Th)-1 product levels such as serum IL-2 and soluble IL-2 receptor (sIL-2R) in serum. Coexisting anxiety and depression are a more severe disorder than depression alone. Studies showed that hypothalamic-pituitary-adrenal (HPA) axis dysregulation is associated with late-life post-traumatic stress disorder (PTSD). We aim to integrate sleep and circadian disruption with inflammatory pathways in depression and anxiety disorders.