A Blue-Enriched Light Intervention Counteracts the Alertness Decrement Among Mine Workers on Extended 12-Hour Night Shift Periods.

OBJECTIVE: The aim of the study is to assess whether a blue-enriched light intervention improves nocturnal alertness and daytime sleep of night workers. METHODS: Thirteen miners performing 12-hour night shifts for 12 consecutive nights were exposed to a baseline and a blue-enriched light condition. All subjects wore an actigraph and completed a Psychomotor Vigilance Task at the beginning and at the end of each shift. Data were analyzed with linear mixed models. RESULTS: In the blue-enriched light condition, the daily increase in median reaction time (RT), mean RT, slowest 10% of RT, and fastest 10% of RT was lower than that observed in the baseline condition between day 1 and 12 ( P ≤ 0.05). CONCLUSIONS: The addition of blue-enriched light during a long period of extended night shifts counteracts most of the daily decline in nocturnal alertness observed in the standard lighting condition, irrespectively of sleep duration and sleep efficiency.

Sex-Specific Retinal Anomalies Induced by Chronic Social Defeat Stress in Mice.

Major depressive disorder (MDD) is one of the most common consequences of chronic stress. Still, there is currently no reliable biomarker to detect individuals at risk to develop the disease. Recently, the retina emerged as an effective way to investigate psychiatric disorders using the electroretinogram (ERG). In this study, cone and rod ERGs were performed in male and female C57BL/6 mice before and after chronic social defeat stress (CSDS). Mice were then divided as susceptible or resilient to stress. Our results suggest that CSDS reduces the amplitude of both oscillatory potentials and a-waves in the rods of resilient but not susceptible males. Similar effects were revealed following the analysis of the cone b-waves, which were faster after CSDS in resilient mice specifically. In females, rod ERGs revealed age-related changes with no change in cone ERGs. Finally, our analysis suggests that baseline ERG can predict with an efficacy up to 71% the expression of susceptibility and resilience before stress exposition in males and females. Overall, our findings suggest that retinal activity is a valid biomarker of stress response that could potentially serve as a tool to predict whether males and females will become susceptible or resilient when facing CSDS.

Chronic Stress Induces Sex-Specific Functional and Morphological Alterations in Corticoaccumbal and Corticotegmental Pathways.

BACKGROUND: The medial prefrontal cortex (mPFC) is part of a complex circuit controlling stress responses by sending projections to different limbic structures including the nucleus accumbens (NAc) and ventral tegmental area (VTA). However, the impact of chronic stress on NAc- and VTA-projecting mPFC neurons is still unknown, and the distinct contribution of these pathways to stress responses in males and females is unclear. METHODS: Behavioral stress responses were induced by 21 days of chronic variable stress in male and female C57BL/6NCrl mice. An intersectional viral approach was used to label both pathways and assess the functional, morphological, and transcriptional adaptations in NAc- and VTA-projecting mPFC neurons in stressed males and females. Using chemogenetic approaches, we modified neuronal activity of NAc-projecting mPFC neurons to decipher their contribution to stress phenotypes. RESULTS: Chronic variable stress induced depressive-like behaviors in males and females. NAc- and VTA-projecting mPFC neurons exhibited sex-specific functional, morphological, and transcriptional alterations. The functional changes were more severe in females in NAc-projecting mPFC neurons, while males exhibited more drastic reductions in dendritic complexity in VTA-projecting mPFC neurons after chronic variable stress. Finally, chemogenetic overactivation of the corticoaccumbal pathway triggered anxiety and behavioral despair in both sexes, while its inhibition rescued the phenotype only in females. CONCLUSIONS: Our results suggest that stress responses in males and females result from pathway-specific changes in the activity of transcriptional programs controlling the morphological and synaptic properties of corticoaccumbal and corticotegmental pathways in a sex-specific fashion.

Good Sleep Quality and Progressive Increments in Vigilance During Extended Night Shifts: A 14-Day Actigraphic Study in Underground Miners.

OBJECTIVE: Assess the change in sleep and vigilance of underground miners during long periods of extended shifts. METHODS: Seventy miners worked 14 consecutive 12-hour day and/or night shifts. Also, they wore an actigraph and completed a visual analog scale for vigilance four times per shift. Linear regression models with mixed effects were used. RESULTS: Sleep efficiency was higher during day shifts than during night shifts (86,5 vs 85.5, P < 0.05) but sleep duration did not differ (6:34 vs 6:44, n.s.). Mean vigilance level at Time 3 (02h00) was significantly lower than that at Time 1 (19h00) during the first 10 night shifts whereas mean vigilance level at Time 4 (05h30) remained significantly lower for the 14 night shifts. CONCLUSIONS: Underground miners exhibit good sleep quality despite evidence of limited circadian adaptation in terms of nighttime vigilance.

Health anxiety and illness-related fears across diverse chronic illnesses: A systematic review on conceptualization, measurement, prevalence, course, and correlates.

BACKGROUND: Patients with chronic diseases commonly report fears of illness or symptoms recurring or worsening. These fears have been addressed from an illness-specific perspective (e.g., fear of cancer recurrence), a generic illness perspective (e.g., fear of progression), and a psychiatric perspective (DSM-5 illness anxiety disorder and somatic symptom disorder). The broader concept of health anxiety (HA) can also be applied to patients with a chronic disease. This review was conducted to investigate the conceptual, theoretical, measurement-overlap, and differences between these distinct perspectives. We also aimed to summarize prevalence, course, and correlates of these fears in different chronic illnesses. METHODS: We used PsycINFO, PubMED, CINAHL, Web of Science, SCOPUS, and PSYNDEX to conduct a systematic review of studies pertaining to these fears in chronic illness published from January 1996 to October 2017. A total of 401 articles were retained. RESULTS: There were commonalities across different conceptualizations and diseases: a high prevalence of clinical levels of fears (>20%), a stable course over time, and a deleterious impact on quality of life. Reviewed studies used definitions, models, and measures that were illness-specific, with only a minority employing a psychiatric perspective, limiting cross-disease generalizability. There appears to be some applicability of DSM-5 disorders to the experience of fear of illness/symptoms in patients with a chronic illness. While conceptualizing HA on a continuum ranging from mild and transient to severe may be appropriate, there is a lack of agreement about when the level of fear becomes 'excessive.' The definitions, models, and measures of HA across chronic illnesses involve affective, cognitive, behavioral, and perceptual features. CONCLUSIONS: The concept of HA may offer a unifying conceptual perspective on the fears of illness/symptoms worsening or returning commonly experienced by those with chronic disease.