The zoster vaccine markedly reduced morbidity from herpes zoster and postherpetic neuralgia among older adults.

Major life stressors, especially those involving interpersonal stress and social rejection, are among the strongest proximal risk factors for depression. In this review, we propose a biologically plausible, multilevel theory that describes neural, physiologic, molecular, and genomic mechanisms that link experiences of social-environmental stress with internal biological processes that drive depression pathogenesis. Central to this social signal transduction theory of depression is the hypothesis that experiences of social threat and adversity up-regulate components of the immune system involved in inflammation. The key mediators of this response, called proinflammatory cytokines, can in turn elicit profound changes in behavior, which include the initiation of depressive symptoms such as sad mood, anhedonia, fatigue, psychomotor retardation, and social-behavioral withdrawal. This highly conserved biological response to adversity is critical for survival during times of actual physical threat or injury. However, this response can also be activated by modern-day social, symbolic, or imagined threats, leading to an increasingly proinflammatory phenotype that may be a key phenomenon driving depression pathogenesis and recurrence, as well as the overlap of depression with several somatic conditions including asthma, rheumatoid arthritis, chronic pain, metabolic syndrome, cardiovascular disease, obesity, and neurodegeneration. Insights from this theory may thus shed light on several important questions including how depression develops, why it frequently recurs, why it is strongly predicted by early life stress, and why it often co-occurs with symptoms of anxiety and with certain physical disease conditions. This work may also suggest new opportunities for preventing and treating depression by targeting inflammation.

Background Sleep disturbance is associated with inflammatory disease risk and all-cause mortality. Here, we assess global evidence linking sleep disturbance, sleep duration, and inflammation in adult humans. Methods A systematic search of English language publications was performed, with inclusion of primary research articles that characterized sleep disturbance and/or sleep duration or performed experimental sleep deprivation, and assessed inflammation by levels of circulating markers. Effect sizes (ES) and 95% confidence intervals (CI) were extracted and pooled using a random effect model. Results A total of 72 studies (n>50000) were analyzed with assessment of C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor α (TNF). Sleep disturbance was associated with higher levels of CRP (ES 0.12; 95% CI 0.05 – 0.19) and IL-6 (ES 0.20; 95% CI 0.08 – 0.31). Shorter sleep duration, but not the extreme of short sleep, was associated with higher levels of CRP (ES 0.09; 95% CI 0.01 – 0.17) but not IL-6 (ES 0.03; 95% CI −0.09 – 0.14). The extreme of long sleep duration was associated with higher levels of CRP (ES 0.17; 95% CI 0.01 – 0.34) and IL-6 (ES 0.11; 95% CI 0.02 – 0.20). Neither sleep disturbances nor sleep duration was associated with TNF. Neither experimental sleep deprivation nor sleep restriction was associated with CRP, IL-6, or TNF. Some heterogeneity among studies was found, but no evidence of publication bias. Conclusions Sleep disturbance and long sleep duration, but not short sleep duration, are associated with increases in markers of systemic inflammation.

Innate immune responses are regulated by microorganisms and cell death, as well as by a third class of stress signal from the nervous and endocrine systems. The innate immune system also feeds back, through the production of cytokines, to regulate the function of the central nervous system (CNS), and this has effects on behaviour. These signals provide an extrinsic regulatory circuit that links physiological, social and environmental conditions, as perceived by the CNS, with transcriptional ‘decision-making’ in leukocytes. CNS-mediated regulation of innate immune responses optimizes total organism fitness and provides new opportunities for therapeutic control of chronic infectious, inflammatory and neuropsychiatric diseases.