Sleep and depression--results from psychobiological studies: an overview

The effect of REM-sleep disruption on affective processing: A systematic review of human and animal experimental studies

Evidence on the importance of rapid-eye-movement sleep (REMS) in processing emotions is accumulating. The focus of this systematic review is the outcomes of experimental REMS deprivation (REMSD), which is the most common method in animal models and human studies on REMSD. This review revealed that variations in the applied REMSD methods were substantial. Animal models used longer deprivation protocols compared with studies in humans, which mostly reported acute deprivation effects after one night. Studies on animal models showed that REMSD causes aggressive behavior, increased pain sensitivity, reduced sexual behavior, and compromised consolidation of fear memories. Animal models also revealed that REMSD during critical developmental periods elicits lasting consequences on affective-related behavior. The few human studies revealed increases in pain sensitivity and suggest stronger consolidation of emotional memories after REMSD. As pharmacological interventions (such as selective serotonin reuptake inhibitors [SSRIs]) may suppress REMS for long periods, there is a clear gap in knowledge regarding the effects and mechanisms of chronic REMS suppression in humans.

Chronic insomnia, REM sleep instability and emotional dysregulation: A pathway to anxiety and depression?

The world-wide prevalence of insomnia disorder reaches up to 10% of the adult population. Women are more often afflicted than men, and insomnia disorder is a risk factor for somatic and mental illness, especially depression and anxiety disorders. Persistent hyperarousals at the cognitive, emotional, cortical and/or physiological levels are central to most theories regarding the pathophysiology of insomnia. Of the defining features of insomnia disorder, the discrepancy between minor objective polysomnographic alterations of sleep continuity and substantive subjective impairment in insomnia disorder remains enigmatic. Microstructural alterations, especially in rapid eye movement sleep ("rapid eye movement sleep instability"), might explain this mismatch between subjective and objective findings. As rapid eye movement sleep represents the most highly aroused brain state during sleep, it might be particularly prone to fragmentation in individuals with persistent hyperarousal. In consequence, mentation during rapid eye movement sleep may be toned more as conscious-like wake experience, reflecting pre-sleep concerns. It is suggested that this instability of rapid eye movement sleep is involved in the mismatch between subjective and objective measures of sleep in insomnia disorder. Furthermore, as rapid eye movement sleep has been linked in previous works to emotional processing, rapid eye movement sleep instability could play a central role in the close association between insomnia and depressive and anxiety disorders.

The efficacy of ball blankets on insomnia in depression in outpatient clinics: A randomised crossover multicentre trial

Many patients with depression report insomnia symptoms that profoundly affect their health and well-being. Non-pharmacological treatments of insomnia may be preferable for some patients. In this randomised crossover trial, we investigated the efficacy of the Protac Ball Blanket® on insomnia among patients with depression. Included patients (n = 45) were diagnosed with unipolar depression, and with subjective insomnia and poor sleep quality (Pittsburgh Sleep Quality Index Score > 5). Each patient slept 2 weeks with a Protac Ball Blanket® and 2 weeks with a control duvet. Randomisation defined the order of the 2-week sleep periods. Patients served as their own control in this design. The primary outcome was changes in total night-time sleep. Secondary outcomes were sleep-onset latency, number of awakenings, wake after sleep onset, daily use of pro necessitate sedatives and hypnotics, subjective sleep quality (Pittsburgh Sleep Quality Index), insomnia severity (Insomnia Severity Index), symptoms of depression (Hamilton Depression Rating Scale, Major Depression Inventory), symptoms of anxiety (Beck Anxiety Index), and patient-reported outcomes concerning interpersonal sensitivity, neurasthenia, anxiety and depression (Self-Reported Symptom State Scale). Paired two-sided t-tests were used to compare the means of the differences of the outcomes. Protac Ball Blanket® increased total night-time sleep by 12.9 min (95% confidence interval: 1.21-24.63, p = 0.031). Among the secondary outcomes, Protac Ball Blanket® decreased Hamilton Depression Rating Scale by 2.78 (95% confidence interval: -5.44; -0.11, p = 0.042) and Insomnia Severity Index by 2.98 (95% confidence interval: -5.45; -0.50, p = 0.020). No changes were observed in sleep-onset latency, number of awakenings, wake after sleep onset, Pittsburgh Sleep Quality Index, Major Depression Inventory, Beck Anxiety Index, Self-Reported Symptom State Scale, and medication use. The results suggest that some patients may benefit from Protac Ball Blanket® as an add-on non-pharmacological treatment to improve sleep in depression.

Association between vitamin C in serum and trouble sleeping based on NHANES 2017-2018

Vitamin C is an important micronutrient for human. Association between vitamin C and trouble sleeping was less studied. Therefore, the purpose of this study was to investigate the possible link between vitamin C in serum and trouble sleeping. The cross-sectional data was derived from the National Health and Nutrition Examination Survey (NHANES, 2017-2018). Trouble sleeping was measured by asking participants: "Have you ever told doctor had trouble sleeping". Responses to this question was "yes" or "no". vitamin C in serum was obtained by measuring the serum samples. We used multivariable binary logistic regressions to examine the possible link between vitamin C in serum and trouble sleeping, and then a subgroup analysis was performed. Moreover, the non-linear relationship between vitamin C in serum and trouble sleeping was further detected using a restricted cubic spline (RCS) model. A total of 3227 participants were included in the study. After adjusting all potential confounders, the results of multivariable logistic regression showed the significant negative association between vitamin C in serum and trouble sleeping(OR = 0.816; 95% CI:0.669 ~ 0.995). The significant inverse association was also found in female(OR = 0.713; 95% CI:0.546 ~ 0.931), age ≤ 65 years(OR = 0.773; 95% CI:0.600 ~ 0.996), and in participants with high cholesterol level(OR = 0.738; 95% CI:0.548 ~ 0.994). In addition, the RCS model demonstrated the significant non-linear relationship between vitamin C in serum and trouble sleeping (P value of nonlinear = 0.010). Our study demonstrates the significant negative association between vitamin C in serum and trouble sleeping.

The effects of physical activity on sleep architecture and mood in naturalistic environments

Physical activity has been found to alter sleep architecture, but these effects have been studied predominantly in the laboratory and the generalizability of these findings to naturalistic environments and longer time intervals, as well as their psychological effects, have not been evaluated. Recent technological advancements in wearable devices have made it possible to capture detailed measures of sleep outside the lab, including timing of specific sleep stages. In the current study, we utilized photoplethysmography coupled with accelerometers and smartphone ambulatory assessment to collect daily measurements of sleep, physical activity and mood in a sample of N = 82 over multi-month data collection intervals. We found a robust inverse relationship between sedentary behavior and physical activity and sleep architecture: both low-intensity and moderate-to-vigorous physical activity were associated with increased NREM sleep and decreased REM sleep, as well as a longer REM latency, while higher levels of sedentary behavior showed the opposite pattern. A decreased REM/NREM ratio and increased REM latency were in turn associated with improved wellbeing, including increased energy, reduced stress and enhanced perceived restfulness of sleep. Our results suggest that physical activity and sleep account for unique variance in a person's mood, suggesting that these effects are at least partially independent.

Cortical signatures of sleep are altered following effective deep brain stimulation for depression

Deep brain stimulation (DBS) of the subcallosal cingulate cortex (SCC) is an experimental therapy for treatment-resistant depression (TRD). Chronic SCC DBS leads to long-term changes in the electrophysiological dynamics measured from local field potential (LFP) during wakefulness, but it is unclear how it impacts sleep-related brain activity. This is a crucial gap in knowledge, given the link between depression and sleep disturbances, and an emerging interest in the interaction between DBS, sleep, and circadian rhythms. We therefore sought to characterize changes in electrophysiological markers of sleep associated with DBS treatment for depression. We analyzed key electrophysiological signatures of sleep-slow-wave activity (SWA, 0.5-4.5 Hz) and sleep spindles-in LFPs recorded from the SCC of 9 patients who responded to DBS for TRD. This allowed us to compare the electrophysiological changes before and after 24 weeks of therapeutically effective SCC DBS. SWA power was highly correlated between hemispheres, consistent with a global sleep state. Furthermore, SWA occurred earlier in the night after chronic DBS and had a more prominent peak. While we found no evidence for changes to slow-wave power or stability, we found an increase in the density of sleep spindles. Our results represent a first-of-its-kind report on long-term electrophysiological markers of sleep recorded from the SCC in patients with TRD, and provides evidence of earlier NREM sleep and increased sleep spindle activity following clinically effective DBS treatment. Future work is needed to establish the causal relationship between long-term DBS and the neural mechanisms underlying sleep.

Exposure to indoor light at night in relation to multiple dimensions of sleep health: findings from the Sister Study

STUDY OBJECTIVE

To examine the association between light at night (LAN) and multiple sleep health dimensions.

METHODS

Among 47 765 Sister Study participants, indoor LAN (TV on in the room, light(s) on in room, light from outside the room, nightlight, no light) and sleep dimensions were self-reported at baseline (2003-2009). We used Poisson regression with robust variance to estimate adjusted prevalence ratios (PR) and 95% confidence intervals (CI) for the cross-sectional associations between LAN and short sleep duration (<7 hours/night), insomnia symptoms (difficulty falling or staying asleep), frequent napping (≥3 naps/week), inconsistent sleep/wake time (differed day-to-day and week-to-week), sleep debt (≥2 hours between longest and shortest duration), recent sleep medication use, and a cumulative poor sleep score (≥3 poor sleep dimensions). Population-attributable risks (PARs) were determined for any light exposure vs. none by race/ethnicity.

RESULTS

Compared to sleeping with no light in the bedroom, sleeping with a TV on was associated with a higher prevalence of most dimensions of poor sleep (e.g. short sleep duration: PR = 1.38, 95% CI: 1.32 to 1.45; inconsistent sleep/wake time: PR = 1.55, 95% CI: 1.44 to 1.66; sleep debt: PR = 1.36, 95% CI: 1.29 to 1.44; poor sleep score: PR = 1.58, 95% CI: 1.48-1.68). PARs tended to be higher for non-Hispanic black women compared to non-Hispanic white women.

CONCLUSIONS

Sleeping with a TV on was associated with poor sleep health among US women, and non-Hispanic black women may be disproportionately burdened.

Detecting major depressive disorder presence using passively-collected wearable movement data in a nationally-representative sample

Major Depressive Disorder (MDD) is a heterogeneous disorder, resulting in challenges with early detection. However, changes in sleep and movement patterns may help improve detection. Thus, this study aimed to explore the utility of wrist-worn actigraphy data in combination with machine learning (ML) and deep learning techniques to detect MDD using a commonly used screening method: Patient Health Questionnaire-9 (PHQ-9). Participants (N = 8,378; MDD Screening = 766 participants) completed the and wore Actigraph GT3X+ for one week as part of the National Health and Nutrition Examination Survey (NHANES). Leveraging minute-level, actigraphy data, we evaluated the efficacy of two commonly used ML approaches and identified actigraphy-derived biomarkers indicative of MDD. We employed two ML modeling strategies: (1) a traditional ML approach with theory-driven feature derivation, and (2) a deep learning Convolutional Neural Network (CNN) approach, coupled with gramian angular field transformation. Findings revealed movement-related features to be the most influential in the traditional ML approach and nighttime movement to be the most influential in the CNN approach for detecting MDD. Using a large, nationally-representative sample, this study highlights the potential of using passively-collected, actigraphy data for understanding MDD to better improve diagnosing and treating MDD.

ChatGPT is not ready yet for use in providing mental health assessment and interventions

Background

Psychiatry is a specialized field of medicine that focuses on the diagnosis, treatment, and prevention of mental health disorders. With advancements in technology and the rise of artificial intelligence (AI), there has been a growing interest in exploring the potential of AI language models systems, such as Chat Generative Pre-training Transformer (ChatGPT), to assist in the field of psychiatry.

Objective

Our study aimed to evaluates the effectiveness, reliability and safeness of ChatGPT in assisting patients with mental health problems, and to assess its potential as a collaborative tool for mental health professionals through a simulated interaction with three distinct imaginary patients.

Methods

Three imaginary patient scenarios (cases A, B, and C) were created, representing different mental health problems. All three patients present with, and seek to eliminate, the same chief complaint (i.e., difficulty falling asleep and waking up frequently during the night in the last 2°weeks). ChatGPT was engaged as a virtual psychiatric assistant to provide responses and treatment recommendations.

Results

In case A, the recommendations were relatively appropriate (albeit non-specific), and could potentially be beneficial for both users and clinicians. However, as complexity of clinical cases increased (cases B and C), the information and recommendations generated by ChatGPT became inappropriate, even dangerous; and the limitations of the program became more glaring. The main strengths of ChatGPT lie in its ability to provide quick responses to user queries and to simulate empathy. One notable limitation is ChatGPT inability to interact with users to collect further information relevant to the diagnosis and management of a patient's clinical condition. Another serious limitation is ChatGPT inability to use critical thinking and clinical judgment to drive patient's management.

Conclusion

As for July 2023, ChatGPT failed to give the simple medical advice given certain clinical scenarios. This supports that the quality of ChatGPT-generated content is still far from being a guide for users and professionals to provide accurate mental health information. It remains, therefore, premature to conclude on the usefulness and safety of ChatGPT in mental health practice.

The relationship between sleep, gut microbiota, and metabolome in patients with depression and anxiety: A secondary analysis of the observational study

BACKGROUND

Growing attention is paid to the association between alterations in the gut microbiota and their metabolites in patients with psychiatric disorders. Our study aimed to determine how gut microbiota and metabolomes are related to the sleep quality among patients with depression and anxiety disorders by analyzing the datasets of our previous study.

METHODS

Samples were collected from 40 patients (depression: 32 patients [80.0%]); anxiety disorders: 8 patients [20.0%]) in this study. Gut microbiomes were analyzed using 16S rRNA gene sequencing and gut metabolomes were analyzed by a mass spectrometry approach. Based on the Pittsburgh Sleep Quality Index (PSQI), patients were categorized into two groups: the insomnia group (PSQI score ≥ 9, n = 20) and the non-insomnia group (PSQI score < 9, n = 20).

RESULTS

The insomnia group showed a lower alpha diversity in the Chao1 and Shannon indices than the non-insomnia group after the false discovery rate (FDR) correction. The relative abundance of genus Bacteroides showed a positive correlation with PSQI scores in the non-insomnia group. The concentrations of glucosamine and N-methylglutamate were significantly higher in the insomnia group than in the non-insomnia group.

CONCLUSIONS

Our findings suggest that specific taxa could affect the sleep quality among patients with depression and anxiety disorders. Further studies are needed to elucidate the impact of sleep on specific gut microbiota and metabolomes in depression and anxiety disorders.

Long-Term Consumption of Green Tea Can Reduce the Degree of Depression in Postmenopausal Women by Increasing Estradiol

Postmenopausal women face a higher risk of depression due to a combination of social and physiological factors. As a beverage rich in a variety of bioactive substances, green tea has significant effects on metabolism, inflammation and endocrine, and may reduce the risk of depression, but few studies have looked at the effects of green tea on postmenopausal women. Therefore, we designed this study to investigate the effects of long-term green tea consumption on inflammation, endocrine and depression levels in postmenopausal women. We investigated a tea-producing village and eventually included 386 postmenopausal women, both in the tea drinking and control groups. The results showed that there were significant differences in the degree of insomnia, degree of depression, BMI, SII and estradiol between the two groups. And, green tea consumption may reduce the risk of depression through the mediating pathway of sleep, SII and estradiol. In summary, long-term green tea consumption can reduce the risk of depression in postmenopausal women by reducing inflammation and increasing estradiol. This kind of living habit deserves further promotion.

Associations between sleep difficulties and health outcomes in treatment-seeking veterans

BACKGROUND

Sleep disturbance in UK Armed Forces personnel appears to be frequent due to factors such as hostile sleeping environments and can persist even once they have transitioned into civilian life. Despite this, there is currently very limited literature surrounding the prevalence and associated factors of insomnia disorder among UK veterans.

AIMS

This study aimed to expand knowledge of the prevalence and associated demographic, military, health and functional outcomes with probable insomnia disorder within a clinical sample of veterans.

METHODS

Treatment-seeking veterans from a national UK mental health charity were invited to complete a questionnaire including socio-demographic, military, health and well-being questions.

RESULTS

Of the sample, 489 (43%) completed the questionnaire. Seventy per cent of the sample reported having probable insomnia disorder. Having probable insomnia disorder was significantly associated with being younger and having physical health problems. Moreover, unadjusted models found associations between probable insomnia disorder and common mental health difficulties, obsessive-compulsive disorder and complex post-traumatic stress disorder.

CONCLUSIONS

The results suggest that many UK veterans with physical and mental health difficulties experience co-morbid insomnia disorder. Therefore, it is important that clinical services are aware of this prevalence and use targeted interventions to reduce the frequency of insomnia disorder in this population.

Cohort profile: The SmartSleep Study, Denmark, combining evidence from survey, clinical and tracking data

PURPOSE

The SmartSleep Study is established to comprehensively assess the impact of night-time smartphone use on sleep patterns and health. An innovative combination of large-scale repeated survey information, high-resolution sensor-driven smartphone data, in-depth clinical examination and registry linkage allows for detailed investigations into multisystem physiological dysregulation and long-term health consequences associated with night-time smartphone use and sleep impairment.

PARTICIPANTS

The SmartSleep Study consists of three interconnected data samples, which combined include 30 673 individuals with information on smartphone use, sleep and health. Subsamples of the study population also include high-resolution tracking data (n=5927) collected via a customised app and deep clinical phenotypical data (n=245). A total of 7208 participants are followed in nationwide health registries with full data coverage and long-term follow-up.

FINDINGS TO DATE

We highlight previous findings on the relation between smartphone use and sleep in the SmartSleep Study, and we evaluate the interventional potential of the citizen science approach used in one of the data samples. We also present new results from an analysis in which we use 803 000 data points from the high-resolution tracking data to identify clusters of temporal trajectories of night-time smartphone use that characterise distinct use patterns. Based on these objective tracking data, we characterise four clusters of night-time smartphone use.

FUTURE PLANS

The unprecedented size and coverage of the SmartSleep Study allow for a comprehensive documentation of smartphone activity during the entire sleep span. The study has been expanded by linkage to nationwide registers, which allow for further investigations into the long-term health and social consequences of night-time smartphone use. We also plan new rounds of data collection in the coming years.

Closed-loop auditory stimulation of sleep slow oscillations: Basic principles and best practices

Sleep is essential for our physical and mental well-being. During sleep, despite the paucity of overt behavior, our brain remains active and exhibits a wide range of coupled brain oscillations. In particular slow oscillations are characteristic for sleep, however whether they are directly involved in the functions of sleep, or are mere epiphenomena, is not yet fully understood. To disentangle the causality of these relationships, experiments utilizing techniques to detect and manipulate sleep oscillations in real-time are essential. In this review, we first overview the theoretical principles of closed-loop auditory stimulation (CLAS) as a method to study the role of slow oscillations in the functions of sleep. We then describe technical guidelines and best practices to perform CLAS and analyze results from such experiments. We further provide an overview of how CLAS has been used to investigate the causal role of slow oscillations in various sleep functions. We close by discussing important caveats, open questions, and potential topics for future research.

The Ponto-Geniculo-Occipital (PGO) Waves in Dreaming: An Overview

Rapid eye movement (REM) sleep is the main sleep correlate of dreaming. Ponto-geniculo-occipital (PGO) waves are a signature of REM sleep. They represent the physiological mechanism of REM sleep that specifically limits the processing of external information. PGO waves look just like a message sent from the pons to the lateral geniculate nucleus of the visual thalamus, the occipital cortex, and other areas of the brain. The dedicated visual pathway of PGO waves can be interpreted by the brain as visual information, leading to the visual hallucinosis of dreams. PGO waves are considered to be both a reflection of REM sleep brain activity and causal to dreams due to their stimulation of the cortex. In this review, we summarize the role of PGO waves in potential neural circuits of two major theories, i.e., (1) dreams are generated by the activation of neural activity in the brainstem; (2) PGO waves signaling to the cortex. In addition, the potential physiological functions during REM sleep dreams, such as memory consolidation, unlearning, and brain development and plasticity and mood regulation, are discussed. It is hoped that our review will support and encourage research into the phenomenon of human PGO waves and their possible functions in dreaming.

The effects of green space on college students' mood

Objective: Less attention has been given to how green space can impact college students' moods. This study aimed to examine whether university students exposed to outdoor and indoor green space-natural and artificial would experience a change in moods compared to students not exposed to green space. Method: Seventy-nine participants were randomly assigned to four different conditions: office without greenery, office with posters of nature, office with green plants, and outside in a garden. The Brunel Mood Scale was used to assess participants' moods before and after spending time in their assigned setting. Results: Results indicated that all participants experienced a decline in tension and fatigue regardless of their assigned setting, yet the decline was less pronounced among participants in the office without greenery. Conclusion: Study findings highlight indoor green space is also conducive to positive moods. Thus, in addition to protecting outside greenery, universities may invest in indoor greenery (e.g., indoor plants, posters/artwork featuring nature) that can be placed in classrooms, libraries, dormitories, and other spaces frequented by students.

Effects of red light on sleep and mood in healthy subjects and individuals with insomnia disorder

Introduction

This study aimed to determine the influence of red light on objective sleep and the relationship between mood and sleep among individuals with insomnia disorder (ID).

Method

57 individuals with insomnia symptoms and 57 healthy participants were randomly divided into three groups (red- and white-light groups, and the black control group), which received different light treatments for 1 h before bedtime. The emotions and subjective alertness of participants were evaluated using Positive and Negative Affect Schedule scales (PANAS) and Karolinska Sleepiness Scale (KSS), their sleeping data were recorded using polysomnography (PSG).

Result

The negative emotion scores were higher in the healthy subject-red light (HS-RL) group than in the HS-white light (WL) and HS-black control (BC) groups (p < 0.001). The anxiety and negative emotion scores were higher in the ID-RL group than in the ID-WL and ID-BC groups (p = 0.007 and p < 0.001, respectively). The KSS scores were lower in the RL group than in the WL and BC groups for both HS and ID group (both p < 0.001). The SOL was shorter in the HS-RL group than in HS-WL group (p = 0.019). Compared with the HS-BC group, the HS-RL group had an increase in microarousal index (MAI) and N1% (p = 0.034 and p = 0.021, respectively), while the total sleep time (TST) and sleep efficiency (SE) decreased (p = 0.001 and p < 0.001, respectively). Compared with the ID-WL group, the SOL was shorter in the ID-RL group (p = 0.043), while TST, SE, number of microarousals (NMA), and numbers of cycles of REM period were increased (p = 0.016, p = 0.046, p = 0.001, and p = 0.041, respectively). Compared with the ID-BC group, the ID-RL group had increases in the SOL, WASO, and the numbers of cycles and NMA in REM period (p = 0.038, p = 0.005, p = 0.045, and p = 0.033, respectively), and a decrease in SE (p = 0.014). The effects of ID-WL (vs. ID-RL group) and ID-BC (vs. ID-RL group) on SOL were mediated by negative emotions (mediating effects were - 37.626 and - 33.768, respectively).

Conclusion

Red light can increase subjective alertness, anxiety, and negative emotions in both healthy subjects and people with ID, which can affect sleep directly or indirectly via the mediating effect of negative emotions.

Ventral pallidal glutamatergic neurons regulate wakefulness and emotion through separated projections

Insomnia is often comorbid with depression, but the underlying neuronal circuit mechanism remains elusive. Recently, we reported that GABAergic ventral pallidum (VP) neurons control wakefulness associated with motivation. However, whether and how other subtypes of VP neurons regulate arousal and emotion are largely unknown. Here, we report glutamatergic VP (VPVglut2) neurons control wakefulness and depressive-like behaviors. Physiologically, the calcium activity of VPVglut2 neurons was increased during both NREM sleep-to-wake transitions and depressive/anxiety-like behaviors in mice. Functionally, activation of VPVglut2 neurons was sufficient to increase wakefulness and induce anxiety/depressive-like behaviors, whereas inhibition attenuated both. Dissection of the circuit revealed that separated projections of VPVglut2 neurons to the lateral hypothalamus and lateral habenula promote arousal and depressive-like behaviors, respectively. Our results demonstrate a subtype of VP neurons is responsible for wakefulness and emotion through separated projections, and may provide new lines for the intervention of insomnia and depression in patients.

Effects of astaxanthin on depressive and sleep symptoms: A narrative mini-review

Major depressive disorder (MDD) is a prevalent psychiatric condition that results in persistent feelings of sadness and loss of interest, imposing a significant economic burden on health systems and society. Impaired sleep is both a symptom and a risk factor for depression. Natural astaxanthin (AST), a carotenoid primarily derived from algae and aquatic animals, possesses multiple pharmacological properties such as anti-inflammatory, anti-apoptotic, and antioxidant stress effects. Prior research suggests that AST may have antidepressant properties. This mini-review highlights the potential mechanisms by which AST can prevent depression, providing novel insights into drug research for depression treatment. Specifically, this mechanism suggests that astaxanthin may improve sleep and thus potentially aid in the treatment of depression.

Bidirectional associations between post-traumatic stress symptoms and sleep quality among older survivors of the 2011 Great East Japan Earthquake and Tsunami

STUDY OBJECTIVES

We sought to examine the bidirectional associations between post-traumatic stress symptoms (PTSS) and sleep quality in a sample of older disaster survivors.

METHODS

We used 4 waves (2010, 2013, 2016, and 2020) of the Iwanuma Study, which included pre-disaster information and 9 years of follow-up data among older survivors of the 2011 Great East Japan Earthquake and Tsunami. Poisson regression analysis was used to examine the bidirectional associations between sleep problems and PTSS.

RESULTS

Individuals reporting sleep problems before the disaster were more likely to develop PTSS after exposure to disaster trauma, while there was no effect modification, i.e. prevalence ratio for sleep problems did not differ by the magnitude of disaster damages. Individuals reporting sleep problems after the disaster were less likely to recover from PTSS, and more likely to develop the delayed onset of PTSS 5 years after the disaster. While individuals who recovered from PTSS 9 years after the disaster were still at slightly higher risk of having sleep problems compared to those who never had PTSS, none of the sleeping problems were found to be significantly prevalent after the Bonferroni correction.

CONCLUSIONS

Pre-disaster sleep problems predicted PTSS onset independently of experiences of disaster trauma. The association between PTSS and sleep problems was bidirectional. Intervening to mitigate lingering sleep problems may benefit the recovery of disaster survivors from post-traumatic symptoms.

Relationships among Postpartum Weight Retention, Stress, and Disinhibited Eating: A Scoping Review

Postpartum weight retention (PPWR) is a significant contributor to maternal cardiometabolic disease risk. The transition to motherhood is a stressful time period in which women report consuming food to cope, an eating behavior that is associated with PPWR. In this scoping review, we identified original research and review articles published since 2010 that examined relationships among PPWR, maternal stress, and disinhibited eating. In total, 16 articles met the inclusion criteria. Findings were inconsistent related to PPWR and stress. PPWR and disinhibited eating were not significantly correlated; however, disinhibition scores were higher during the postpartum period compared to prenatally. Stress and disinhibited eating were directly correlated in 4 studies. Our findings suggest these concepts, particularly disinhibited eating, have not been robustly examined during the postpartum period. Additionally, instruments used to measure maternal stress vary widely and should be further studied and refined.

Subjective and objective sleep and circadian parameters as predictors of depression-related outcomes: A machine learning approach in UK Biobank

BACKGROUND

Sleep and circadian disruption are associated with depression onset and severity, but it is unclear which features (e.g., sleep duration, chronotype) are important and whether they can identify individuals showing poorer outcomes.

METHODS

Within a subset of the UK Biobank with actigraphy and mental health data (n = 64,353), penalised regression identified the most useful of 51 sleep/rest-activity predictors of depression-related outcomes; including case-control (Major Depression (MD) vs. controls; postnatal depression vs. controls) and within-case comparisons (severe vs. moderate MD; early vs. later onset, atypical vs. typical symptoms; comorbid anxiety; suicidality). Best models (of lasso, ridge, and elastic net) were selected based on Area Under the Curve (AUC).

RESULTS

For MD vs. controls (n_(MD) = 24,229; n_(control) = 40,124), lasso AUC was 0.68, 95 % confidence interval (CI) 0.67-0.69. Discrimination was reasonable for atypical vs. typical symptoms (n_(atypical) = 958; n_(typical) = 18,722; ridge: AUC 0.74, 95 % CI 0.71-0.77) but poor for remaining models (AUCs 0.59-0.67). Key predictors across most models included: difficulty getting up, insomnia symptoms, snoring, actigraphy-measured daytime inactivity and lower morning activity (~8 am). In a distinct subset (n = 310,718), the number of these factors shown was associated with all depression outcomes.

LIMITATIONS

Analyses were cross-sectional and in middle-/older aged adults: comparison with longitudinal investigations and younger cohorts is necessary.

DISCUSSION

Sleep and circadian measures alone provided poor to moderate discrimination of depression outcomes, but several characteristics were identified that may be clinically useful. Future work should assess these features alongside broader sociodemographic, lifestyle and genetic features.

Functional connectivity between dorsal attention and default mode networks mediates subjective sleep duration and depression in young females

BACKGROUND

Depression prevails throughout the world. Young females are more likely to suffer from depression because of lack of sleep.

METHODS

We recruited 405 young female participants to assess their subjective sleep duration and self-rating depression. The resting-state magnetic resonance imaging (rs-fMRI) data were collected to identify the brain regions related to sleep duration and depression, and a mediating model was established among sleep duration, depression and functional connectivity (FC) of rs-fMRI.

RESULTS

Correlation analysis indicated that subjective sleep duration was negatively associated with self-rating depression in young females (r = -0.22, p < .001). The network connectivity between dorsal attention network (DAN) and default mode network (DMN) positively correlated with self-rating depression (r = 0.13, p < .05), and negatively correlated with subjective sleep duration (r = -0.14, p < .01). Furthermore, the mediation analysis revealed that the FC of DAN-DMN significantly mediated the effect of sleep duration on depression.

LIMITATIONS

The study was a cross-section design and the sleep duration of the participants was subjectively reported. Future studies should consider to track the participants longitudinally and to measure the objective sleep duration by actigraph or polysomnography.

CONCLUSIONS

The participants with less sleep duration are more prone to develop depression feelings. The FC of DAN-DMN mediated the effect of sleep duration on depression. Thus, the FC of DAN-DMN could be consider as a neural target to relieve depression by increasing sleep duration in young females.

Sleep physiology, pathophysiology, and sleep hygiene

Despite sleep's fundamental role in maintaining and improving physical and mental health, many people get less than the recommended amount of sleep or suffer from sleeping disorders. This review highlights sleep's instrumental biological functions, various sleep problems, and sleep hygiene and lifestyle interventions that can help improve sleep quality. Quality sleep allows for improved cardiovascular health, mental health, cognition, memory consolidation, immunity, reproductive health, and hormone regulation. Sleep disorders, such as insomnia, sleep apnea, and circadian-rhythm-disorders, or disrupted sleep from lifestyle choices, environmental conditions, or other medical issues can lead to significant morbidity and can contribute to or exacerbate medical and psychiatric conditions. The best treatment for long-term sleep improvement is proper sleep hygiene through behavior and sleep habit modification. Recommendations to improve sleep include achieving 7 to 9 h of sleep, maintaining a consistent sleep/wake schedule, a regular bedtime routine, engaging in regular exercise, and adopting a contemplative practice. In addition, avoiding many substances late in the day can help improve sleep. Caffeine, alcohol, heavy meals, and light exposure later in the day are associated with fragmented poor-quality sleep. These sleep hygiene practices can promote better quality and duration of sleep, with corresponding health benefits.

Metabotropic glutamate receptor function and regulation of sleep-wake cycles

Metabotropic glutamate (mGlu) receptors are the most abundant family of G-protein coupled receptors and are widely expressed throughout the central nervous system (CNS). Alterations in glutamate homeostasis, including dysregulations in mGlu receptor function, have been indicated as key contributors to multiple CNS disorders. Fluctuations in mGlu receptor expression and function also occur across diurnal sleep-wake cycles. Sleep disturbances including insomnia are frequently comorbid with neuropsychiatric, neurodevelopmental, and neurodegenerative conditions. These often precede behavioral symptoms and/or correlate with symptom severity and relapse. Chronic sleep disturbances may also be a consequence of primary symptom progression and can exacerbate neurodegeneration in disorders including Alzheimer's disease (AD). Thus, there is a bidirectional relationship between sleep disturbances and CNS disorders; disrupted sleep may serve as both a cause and a consequence of the disorder. Importantly, comorbid sleep disturbances are rarely a direct target of primary pharmacological treatments for neuropsychiatric disorders even though improving sleep can positively impact other symptom clusters. This chapter details known roles of mGlu receptor subtypes in both sleep-wake regulation and CNS disorders focusing on schizophrenia, major depressive disorder, post-traumatic stress disorder, AD, and substance use disorder (cocaine and opioid). In this chapter, preclinical electrophysiological, genetic, and pharmacological studies are described, and, when possible, human genetic, imaging, and post-mortem studies are also discussed. In addition to reviewing the important relationships between sleep, mGlu receptors, and CNS disorders, this chapter highlights the development of selective mGlu receptor ligands that hold promise for improving both primary symptoms and sleep disturbances.

Experiences of adult patients living with depression-related insomnia: a qualitative systematic review protocol

OBJECTIVE

The objective of this review is to identify and synthesize the best available evidence on how adult patients experience living with depression-related insomnia. In particular, the review will examine the experiences related to pharmacological and non-pharmacological interventions to improve sleep.

INTRODUCTION

Approximately 80% to 90% of patients with depression have insomnia, which is associated with substantial personal and social costs. Despite these costs, insomnia is often underdiagnosed and viewed as a symptom that disappears when depression abates. However, research indicates that insomnia and depression are overlapping but distinct disorders. Thus, it is important to treat both disorders simultaneously, as improving sleep may, in turn, ease core symptoms of depression. Optimal care and treatment rely on patients' experiences of insomnia and their attitudes toward treatment options. Therefore, it is important to synthesize evidence of patients' experiences of living with insomnia, and the experiences of pharmacological and non-pharmacological sleep interventions, to understand the consequences of insomnia and to optimize sleep interventions.

INCLUSION CRITERIA

This systematic review will synthesize qualitative studies exploring how adults with depression experience living with insomnia and how they experience pharmacological or non-pharmacological sleep interventions. Both inpatient and outpatient populations will be considered.

METHODS

Databases to be searched include MEDLINE, Embase, CINAHL, PsycINFO, Cochrane Database of Systematic Reviews, Cochrane CENTRAL, SveMed+, Scopus, and Web of Science Core Collection. Google Scholar and ProQuest Dissertations and Theses will be searched for unpublished studies. Studies in English, German, Danish, Swedish, and Norwegian will be included. Databases will be searched from their inception to the present date. All studies will be screened against the inclusion criteria and critically appraised for methodological quality. Findings will be pooled using meta-aggregation, and a ConQual Summary of Findings will be presented.

SYSTEMATIC REVIEW REGISTRATION NUMBER

PROSPERO CRD42021276048.

Extreme racism-related events and poor sleep in African-American women

RATIONALE

Much of the research linking racism-related stressors to poor health has focused on fairly non-violent forms of racism that directly impact individuals under study. Exposure to particularly extreme and/or violent racist events are increasingly visible via smartphone recordings and social media, with consistent anecdotal reports of the effects of seeing and hearing about these events on sleep among minorities who racially identify with the victims.

OBJECTIVE

This study examines whether exposure to direct and vicarious racism-related events (RREs), including more extreme events, are associated with sleep quality. Additionally, we examine effects of less and more violent direct RREs and vicarious RREs witnessed in person and via social media.

METHODS

Among 422 African-American women, we assessed exposure to RREs using a modified version of the Race-Related Events Scale and assessed sleep quality using the Pittsburgh Sleep Quality Index (PSQI). Linear regression analyses were used to model continuous global sleep.

RESULTS

Direct (β = 0.24 [95% CI: 0.13, 0.35]) RREs were associated with worse continuous global sleep quality scores in analyses adjusted for sociodemographics and risk factors for poor sleep. More violent direct RREs (β = 0.59 [95% CI: 0.30, 0.89]) had stronger associations with poor sleep quality than less violent direct RREs (β = 0.25 [95% CI: 0.11, 0.40]). Vicarious RREs overall (β = 0.04 [95% CI: 0.14, 0.21]) and those witnessed via social media (β = -0.07 [95% CI: 0.29, 0.14]) were not associated with global sleep quality; conversely, vicarious RREs witnessed in person were (β = 0.52 [95% CI: 0.21, 0.83]).

CONCLUSION

Extreme, direct experiences of racism, particularly those that are violent in nature, are associated with poor sleep quality. However, extreme vicarious experiences are not-- unless witnessed in person.

Stress, mental ill-health and functional somatic syndromes in incident and chronic sleep disturbance in a general adult population

Objective

Sleep disturbance may constitute health problems for the afflicted individual, but documentation of its chronicity is sparse. The objective was to investigate the extent to which incident and chronic sleep disturbance are associated with stress, mental ill-health and functional somatic syndromes.

Design

This was a prospective, longitudinal study with 3-year interval between two assessments (T1 and T2), with a population-based sample forming groups with incident sleep disturbance (disturbance only at T2; n = 303), chronic sleep disturbance (disturbance at T1 and T2; n = 343) and without sleep disturbance (neither at T1 nor T2; n = 1421). Questionnaire data were used at T2 of physician-based diagnosis of anxiety disorder, depression, exhaustion syndrome, and functional somatic syndrome as well as of degree of stress, burnout, anxiety and depression.

Results

Significant associations were found between chronic sleep disturbance and all four diagnoses (odds ratios = 1.74-2.19), whereas incident sleep disturbance was associated only with exhaustion syndrome and depression (odds ratios = 2.18-2.37). Degree of stress, burnout, anxiety and depression increased significantly from the referents to incident and chronic sleep disturbance, in that order (eta² = 0.083-0.166), except for the two latter groups not differing in depression.

Conclusion

The findings imply that healthcare professionals should be observant regarding various conditions of, apart from stress, mental ill-health and functional somatic syndromes in patients who present themselves with sleep disturbance, and in particular chronic disturbance.

People with passive sleep delay have more severe depression and sleep problems than those with active sleep delays-a cross-sectional study after the COVID-19 pandemic

Objective

This study was designed to investigate the effect of different types of sleep delay in depression and sleep characteristics after the pandemic. Meanwhile, risk factors for depression were also explored.

Methods

The survey was conducted in Wuhan from March 1 to May 30, 2021, and participants were recruited through a snowball process. A total of 1,583 people with sleep delays responded to the invitation, of which 1,296 were enrolled. Participants filled out a questionnaire including social demographics, sleep characteristics, Social Support Rating Scale (SSRS), Pittsburgh Sleep Quality Index (PSQI) and Patient Health Questionnaire-9 (PHQ-9).

Results

There were no significant differences in sex, social support and level of education between the two types of sleep delay (p = 0.961, p = 0.110, p = 0.090), but the average age of the passive sleep delay group was higher (p = 0.015). And most people with active sleep delay were caused by the use of electronic devices (73.6%), while most people with passive sleep delay were caused by work or study tasks (73.2%), with a significant difference between the two groups (p < 0.001). People who actively delayed sleep had more regular sleep (p < 0.001), better sleep quality and longer sleep duration (p < 0.001, p < 0.001). In addition, although they delayed sleep more frequently (p < 0.001), they had significantly lower depression degree than people who passively delayed sleep (p < 0.001).

Conclusions

Passive sleep delays, usually caused by work or study, has higher levels of depression and more adverse sleep behaviors than active sleep delay. The findings help further understand the effects of delayed sleep and provide insight for people with delayed sleep to evaluate their own condition. Future studies are required to standardize and accurately classify sleep delay and further explore it.

Chronic Unpredictable Mild Stress Model of Depression: Possible Sources of Poor Reproducibility and Latent Variables

Major depressive disorder (MDD) is one of the most common mood disorders worldwide. A lack of understanding of the exact neurobiological mechanisms of depression complicates the search for new effective drugs. Animal models are an important tool in the search for new approaches to the treatment of this disorder. All animal models of depression have certain advantages and disadvantages. We often hear that the main drawback of the chronic unpredictable mild stress (CUMS) model of depression is its poor reproducibility, but rarely does anyone try to find the real causes and sources of such poor reproducibility. Analyzing the articles available in the PubMed database, we tried to identify the factors that may be the sources of the poor reproducibility of CUMS. Among such factors, there may be chronic sleep deprivation, painful stressors, social stress, the difference in sex and age of animals, different stress susceptibility of different animal strains, handling quality, habituation to stressful factors, various combinations of physical and psychological stressors in the CUMS protocol, the influence of olfactory and auditory stimuli on animals, as well as the possible influence of various other factors that are rarely taken into account by researchers. We assume that careful inspection of these factors will increase the reproducibility of the CUMS model between laboratories and allow to make the interpretation of the obtained results and their comparison between laboratories to be more adequate.

Investigating the combined effect of ALAN and noise on sleep by simultaneous real-time monitoring using low-cost smartphone devices

The association between artificial light at night (ALAN) and noise, on the one hand, and sleep, on the other, is well established. Yet studies investigating these associations have been infrequent and mostly conducted in controlled laboratory conditions. As a result, little is known about the applicability of their results to real-world settings. In this paper, we attempt to bridge this knowledge gap by carrying out an individual-level real-world study, involving 72 volunteers from different urban localities in Israel. The survey participants were asked to use their personal smartphones and smartwatches to monitor sleep patterns for 30 consecutive days, while ALAN and noise exposures were monitored in parallel, with inputs reported each second. The volunteers were also asked to fill in a questionnaire about their individual attributes, daily habits, room settings, and personal health, to serve as individual-level controls. Upon cointegration, the assembled data were co-analyzed using bivariate and multivariate statistical tools. As the study reveals, the effect of ALAN and noise on sleep largely depends on when the exposure occurred, that is, before sleep or during sleep. In particular, the effect of ALAN exposure was found to be most pronounced if it occurred before sleep, while exposure to noise mattered most if it occurred during the sleep phase. As the study also reveals, the effects of ALAN and noise appear to amplify each other, with a 14-15.3% reduction in sleep duration and an 8-9% reduction in sleep efficiency observed at high levels of ALAN-noise exposures. The study helped to assemble a massive amount of real-time observations, enabling a robust individual-level analysis.

A broken circadian clock: The emerging neuro-immune link connecting depression to cancer

Circadian clocks orchestrate daily rhythms in many organisms and are essential for optimal health. Circadian rhythm disrupting events, such as jet-lag, shift-work, night-light exposure and clock gene alterations, give rise to pathologic conditions that include cancer and clinical depression. This review systemically describes the fundamental mechanisms of circadian clocks and the interacting relationships among a broken circadian clock, cancer and depression. We propose that this broken clock is an emerging link that connects depression and cancer development. Importantly, broken circadian clocks, cancer and depression form a vicious feedback loop that threatens systemic fitness. Arresting this harmful loop by restoring normal circadian rhythms is a potential therapeutic strategy for treating both cancer and depression.

Sleep architecture modifications after double chronotherapy: A case series of bipolar depressed inpatients

The aim of this study is to objectively evaluate sleep architecture changes of depressed bipolar subjects treated with chronoterapeutics. Eleven depressed bipolar inpatients received 3 cycles of Total Sleep Deprivation, followed by daily light therapy sessions for one week. Polysomnography was performed before and after the treatment. Depressive symptoms significantly reduced, and sleep architecture changed with significant differences in N2% and N3% and REM density. Change in N3% was also positively correlated to depressive symptoms reduction. Although, previous studies reported sleep architecture changes after chronoterapeutics in unipolar depression, this is the first study to demonstrate changes also in bipolar depressed subjects.

The association between social engagement and depressive symptoms in middle-aged and elderly Chinese: A longitudinal subgroup identification analysis under causal inference frame

Background

Studies have suggested that there is a significant association between social engagement and depression symptoms. However, this association may differ in people with different features such as different sociodemographic characteristics and health conditions.

Methods

Research data were obtained from the CHARLS database. The causal inference was performed with the propensity score. We used the linear mixed-effects model tree algorithm under the causal inference frame for subgroup identification analysis.

Results

We included 13,521 participants, and the median follow-up time is 4 years. Under the casual inference frame, the association between social engagement and depression symptoms is confirmed for all included individuals (OR = 0.957, P = 0.016; 95%CI: 0.923–0.992). Using the linear mixed-effects model tree, we found two subgroups, including middle-aged and elderly residents who live in rural areas with <6 h of sleep and those living in urban areas, could benefit more from social engagement. After using the propensity score method, all the two subgroups selected are statistically significant (P = 0.007; P = 0.013) and have a larger effect size (OR = 0.897, 95%CI: 0.830–0.971; OR = 0.916, 95%CI: 0.854–0.981) than the whole participants. As for sex difference, this associations are statistically significant in male (OR: 0.935, P = 0.011, 95%CI: 0.888–0.985) but not in female (OR: 0.979, P = 0.399, 95%CI: 0.931–1.029).

Conclusions

Our findings indicate that social engagement may reduce the risks of depressive symptoms among all individuals. The identified subgroups of middle-aged and elderly residents who live in rural areas with <6 h of sleep and those who live in urban areas may benefit more from the social engagement than the whole participants.

A Review of Equine Sleep: Implications for Equine Welfare

Sleep is a significant biological requirement for all living mammals due to its restorative properties and its cognitive role in memory consolidation. Sleep is ubiquitous amongst all mammals but sleep profiles differ between species dependent upon a range of biological and environmental factors. Given the functional importance of sleep, it is important to understand these differences in order to ensure good physical and psychological wellbeing for domesticated animals. This review focuses specifically on the domestic horse and aims to consolidate current information on equine sleep, in relation to other species, in order to (a) identify both quantitatively and qualitatively what constitutes normal sleep in the horse, (b) identify optimal methods to measure equine sleep (logistically and in terms of accuracy), (c) determine whether changes in equine sleep quantity and quality reflect changes in the animal's welfare, and (d) recognize the primary factors that affect the quantity and quality of equine sleep. The review then discusses gaps in current knowledge and uses this information to identify and set the direction of future equine sleep research with the ultimate aim of improving equine performance and welfare. The conclusions from this review are also contextualized within the current discussions around the “social license” of horse use from a welfare perspective.

Extreme racism-related events and poor sleep in African-American women

RATIONALE

Much of the research linking racism-related stressors to poor health has focused on fairly non-violent forms of racism that directly impact individuals under study. Exposure to particularly extreme and/or violent racist events are increasingly visible via smartphone recordings and social media, with consistent anecdotal reports of the effects of seeing and hearing about these events on sleep among minorities who racially identify with the victims.

OBJECTIVE

This study examines whether exposure to direct and vicarious racism-related events (RREs), including more extreme events, are associated with sleep quality. Additionally, we examine effects of less and more violent direct RREs and vicarious RREs witnessed in person and via social media.

METHODS

Among 422 African-American women, we assessed exposure to RREs using a modified version of the Race-Related Events Scale and assessed sleep quality using the Pittsburgh Sleep Quality Index (PSQI). Linear regression analyses were used to model continuous global sleep.

RESULTS

Direct (β = 0.24 [95% CI: 0.13, 0.35]) RREs were associated with worse continuous global sleep quality scores in analyses adjusted for sociodemographics and risk factors for poor sleep. More violent direct RREs (β = 0.59 [95% CI: 0.30, 0.89]) had stronger associations with poor sleep quality than less violent direct RREs (β = 0.25 [95% CI: 0.11, 0.40]). Vicarious RREs overall (β = 0.04 [95% CI: 0.14, 0.21]) and those witnessed via social media (β = -0.07 [95% CI: 0.29, 0.14]) were not associated with global sleep quality; conversely, vicarious RREs witnessed in person were (β = 0.52 [95% CI: 0.21, 0.83]).

CONCLUSION

Extreme, direct experiences of racism, particularly those that are violent in nature, are associated with poor sleep quality. However, extreme vicarious experiences are not-- unless witnessed in person.

Childhood trauma and gender: Synergistic and additive effects on sleep in healthy young adults

OBJECTIVES

To examine whether gender moderates the effects of childhood trauma on subjective and objective sleep measures.

DESIGN

Secondary data analysis, exploratory SETTINGS: Sleep research lab PARTICIPANTS: A total of 213 men and 278 women aged 18-30 completed subjective measures. A subsample of 172 participants without any psychiatric, medical, or sleep disorders completed objective polysomnography for 1 night at baseline, before sleep manipulation.

MEASUREMENTS

Subjective measures: Childhood Trauma Questionnaire (CTQ), Pittsburgh Sleep Quality Index, Insomnia Severity Index, and Epworth Sleepiness Scale. Objective measures: Standard polysomnography measures. Multiple regressions determined whether gender moderated CTQ score on any objective or subjective sleep measures. If gender was not a moderator, we examined additive effects of gender and CTQ score. Models were adjusted for race and age.

RESULTS

Gender and CTQ score interactions were non-significant for both subjective (p > .675) and objective (p > .110) sleep. Women demonstrated better subjective sleep quality (Pittsburgh Sleep Quality Index, B = -0.264, p = .041) and more delta sleep than men (B = 3.032, p =.005). Greater CTQ score was associated with increased sleepiness (Epworth Sleepiness Scale, B = 0.029, p = .042), increased insomnia severity (Insomnia Severity Index, B = 0.027, p = .005), and lower REM density (B = -0.132, p = .045).

CONCLUSION

Our finding of greater delta sleep and better subjective overall sleep quality in women suggests that, among people without comorbidities, women may experience better sleep. Childhood trauma is associated with objective and subjective sleep measures, but this association is non-specific to gender. Clear links between childhood trauma and sleep are detectable in a sample of healthy sleepers with no comorbidities.

Impact of spaceflight stressors on behavior and cognition: A molecular, neurochemical, and neurobiological perspective

The response of the human body to multiple spaceflight stressors is complex, but mounting evidence implicate risks to CNS functionality as significant, able to threaten metrics of mission success and longer-term behavioral and neurocognitive health. Prolonged exposure to microgravity, sleep disruption, social isolation, fluid shifts, and ionizing radiation have been shown to disrupt mechanisms of homeostasis and neurobiological well-being. The overarching goal of this review is to document the existing evidence of how the major spaceflight stressors, including radiation, microgravity, isolation/confinement, and sleep deprivation, alone or in combination alter molecular, neurochemical, neurobiological, and plasma metabolite/lipid signatures that may be linked to operationally-relevant behavioral and cognitive performance. While certain brain region-specific and/or systemic alterations titrated in part with neurobiological outcome, variations across model systems, study design, and the conspicuous absence of targeted studies implementing combinations of spaceflight stressors, confounded the identification of specific signatures having direct relevance to human activities in space. Summaries are provided for formulating new research directives and more predictive readouts of portending change in neurobiological function.

Slow Wave Sleep Deficits in the Flinders Sensitive Line Rodent Model of Depression: Effects of Medial Forebrain Bundle Deep-Brain Stimulation

Major Depressive Disorder (MDD) is an affective disorder typically accompanied by sleep disturbances. Deep brain stimulation (DBS) of the medial forebrain bundle (MFB) is an emerging intervention for treatment-resistant depression, but its effect on sleep has not been closely examined. Here we aimed to characterise sleep deficits in the Flinders sensitive line, an established rodent model of depression, and investigate the consequences of MFB stimulation on sleep-related phenotypes. Rats were implanted with bilateral stimulation electrodes in the MFB, surface electrodes to record electrocorticography and electromyography for sleep scoring and electrodes within the prelimbic cortex, nucleus accumbens (NAc) and dorsal hippocampus. Recordings of sleep and oscillatory activity were conducted prior to and following twenty-four hours of MFB stimulation. Behavioural anti-depressant effects were monitored using the forced swim test. Previously unreported abnormalities in the Flinders sensitive line rats were observed during slow wave sleep, including decreased circadian amplitude of its rhythm, a reduction in slow wave activity and elevated gamma band oscillations. Previously established rapid eye movement sleep deficits were replicated. MFB stimulation had anti-depressant effects on behavioural phenotype, but did not significantly impact sleep architecture; it suppressed elevated gamma activity during slow wave sleep in the electrocorticogram and prelimbic cortex signals. Diverse abnormalities in Flinders sensitive line rats emphasise slow wave sleep as a state of dysfunction in affective disorders. MFB stimulation is able to affect behaviour and sleep physiology without influencing sleep architecture. Gamma modulation may represent a component of antidepressant mechanism.

Associations between sleep problems and domains relevant to daytime functioning and clinical symptomatology in autism: A meta-analysis

Autistic individuals experience significantly higher rates of sleep problems compared to the general population, which negatively impacts various aspects of daytime functioning. The strength of associations across domains of functioning has not yet been summarized across studies. The present meta-analysis examined the strength of associations between sleep problems and various domains of daytime functioning in autistic individuals. Searches were conducted in EMBASE, PubMed, Web of Science, and Google Scholar through May 2020. Inclusion criteria were: an index of sleep disturbance in individuals diagnosed with autism spectrum disorder (ASD); data collected prior to any sleep-related intervention; statistical data indicating relations between sleep problems and outcomes relevant to behavior, cognition, and physical or mental health. Exclusion criteria were: statistics characterizing the relationship between sleep disturbance and outcome variables that partialled out covariates; studies examining correlations between different measures of sleep disturbance. Participants totaled 15,074 from 49 published articles and 51 samples, yielding 209 effect sizes. Sleep problems were significantly associated with more clinical symptomatology and worse daytime functioning. Subgroup analyses demonstrated that sleep problems were most strongly associated with internalizing and externalizing symptoms and executive functioning, followed by core autism symptoms, family factors, and adaptive functioning. Findings highlight the far-reaching consequences of sleep problems on daytime functioning for autistic individuals and support the continued prioritization of sleep as a target for intervention through integrated care models to improve wellbeing. LAY SUMMARY: Autistic individuals experience higher rates of sleep problems, such as difficulty falling asleep and staying asleep, compared to the general population. We quantitatively summarized the literature about how sleep problems are related to different aspects of daytime functioning to identify areas that may be most affected by sleep. Sleep problems were related to all areas assessed, with the strongest associations for mood and anxiety symptoms. We recommend prioritizing sleep health in autistic individuals to improve wellbeing and quality of life.

Evening light environments can be designed to consolidate and increase the duration of REM-sleep

Evening exposure to short-wavelength light has disruptive effects on circadian rhythms and sleep. These effects can be mitigated by blocking short-wavelength (blue) frequencies, which has led to the development of evening blue-depleted light environments (BDLEs). We have previously reported that residing 5 days in an evening BDLE, compared with residing in a normal indoor light environment of similar photopic lux, advances circadian rhythms and increases the duration of rapid eye movement (REM) sleep in a randomized cross-over trial with twelve healthy participants. The current study extends these findings by testing whether residing in the evening BDLE affects the consolidation and microstructure of REM sleep in the same sample. Evening BDLE significantly reduces the fragmentation of REM sleep (p = 0.0003), and REM sleep microarousals in (p = 0.0493) without significantly changing REM density or the latency to first REM sleep episode. Moreover, the increased accumulation of REM sleep is not at the expense of NREM stage 3 sleep. BDLE further has a unique effect on REM sleep fragmentation (p = 0.0479) over and above that of circadian rhythms phase-shift, indicating a non-circadian effect of BDLE. If these effects can be replicated in clinical populations, this may have a therapeutic potential in disorders characterized by fragmented REM sleep.

Is paradoxical sleep setting up innate and acquired complex sensorimotor and adaptive behaviours?: A proposed function based on literature review

We summarize here the progress in identifying the neuronal network as well as the function of paradoxical sleep and the gaps of knowledge that should be filled in priority. The core system generating paradoxical sleep localized in the brainstem is now well identified, and the next step is to clarify the role of the forebrain in particular that of the hypothalamus including the melanin-concentrating hormone neurons and of the basolateral amygdala. We discuss these two options, and also the discovery that cortical activation during paradoxical sleep is restricted to a few limbic cortices activated by the lateral supramammillary nucleus and the claustrum. Such activation nicely supports the findings recently obtained showing that neuronal reactivation occurs during paradoxical sleep in these structures, and induces both memory consolidation of important memory and forgetting of less relevant ones. The question that still remains to be answered is whether paradoxical sleep is playing more crucial roles in processing emotional and procedural than other types of memories. One attractive hypothesis is that paradoxical sleep is responsible for erasing negative emotional memories, and that this function is not properly functioning in depressed patients. On the other hand, the presence of a muscle atonia during paradoxical sleep is in favour of a role in procedural memory as new types of motor behaviours can be tried without harm during the state. In a way, it also fits with the proposed role of paradoxical sleep in setting up the sensorimotor system during development.

Nighttime smartphone use and changes in mental health and wellbeing among young adults: a longitudinal study based on high-resolution tracking data

Frequent nighttime smartphone use can disturb healthy sleep patterns and may adversely affect mental health and wellbeing. This study aims at investigating whether nighttime smartphone use increases the risk of poor mental health, i.e. loneliness, depressive symptoms, perceived stress, and low life satisfaction among young adults. High-dimensional tracking data from the Copenhagen Network Study was used to objectively measure nighttime smartphone activity. We recorded more than 250,000 smartphone activities during self-reported sleep periods among 815 young adults (university students, mean age: 21.6 years, males: 77%) over 16 weekdays period. Mental health was measured at baseline using validated measures, and again at follow-up four months later. Associations between nighttime smartphone use and mental health were evaluated at baseline and at follow-up using multiple linear regression adjusting for potential confounding. Nighttime smartphone use was associated with a slightly higher level of perceived stress and depressive symptoms at baseline. For example, participants having 1-3 nights with smartphone use (out of 16 observed nights) had on average a 0.25 higher score (95%CI:0.08;0.41) on the Perceived stress scale ranging from 0 to 10. These differences were small and could not be replicated at follow-up. Contrary to the prevailing hypothesis, nighttime smartphone use is not strongly related to poor mental health, potentially because smartphone use is also a social phenomenon with associated benefits for mental health.

Patient characteristics as predictors of sleep disturbances in multimorbid primary care patients - A secondary analysis

OBJECTIVE

The aim of the study was to identify patient characteristics (adult attachment, health status, number and severity of chronic conditions, social support) predictive sleep disturbances after 12 months.

METHODS

In a secondary analysis of a prospective longitudinal study dealing with adult attachment and self-management, attachment- and health-related characteristics, socio-demographic data at baseline and symptoms of insomnia at the follow up (12 month later) was recorded by 219 patients between the ages of 50 and 85 years with multimorbidity in primary care. Adult attachment was measured by the ECR-RD12. The overall health status was measured using a visual analogue scale (VAS) and a standardized list of chronic conditions. The number and severity of chronic diseases (CIRS-G) was assessed by general practitioners (GPs). Sleep disturbances was measured by the ISI 12 month later.

RESULTS

Approximately 19% of the respondents were found to have clinically relevant symptoms of insomnia, and a further 34% to be subclinical insomnia. Attachment-related anxiety, a poorer perceived social support, the number of chronic conditions and a better general health status could predict higher levels of sleep disturbance after 12 month.

CONCLUSION

Sleep disorders can play a major role in patients with multimorbidity. Attachment anxiety and lack of social support may also be possible risk factors for the development of sleep disturbances.

Sleep disorders and non-sleep circadian disorders predict depression: a systematic review and meta-analysis of longitudinal studies

Patients with depression often suffer from sleep disorders and non-sleep circadian disorders. However, whether they precede and predict subsequent depression is unclear. We conducted a meta-analysis of studies on sleep disorders and non-sleep circadian disorders. We found insomnia, hypersomnia, short and long sleep duration, obstructive sleep apnea, restless legs syndrome and eveningness orientation at baseline all led to subsequent depression. Those with propensity to late meal patterns, heightened levels of cortisol in awakening response and low robustness of rest-activity rhythm at baseline had higher risks for later depression. Among insomnia subtypes, difficulty initiating sleep and difficulty maintaining sleep predicted future depression. Notably, persistent insomnia at baseline contributed to more than two-fold risk of incident depression compared to insomnia. Moreover, insomnia symptom numbers showed dose-dependent relationship with the incident depression. In conclusion, different types of sleep disorders and non-sleep circadian disorders were proven to be risk factors of subsequent depression, and mechanisms underlying the relationship between sleep disorders, non-sleep circadian disorders and subsequent depression should be further elucidated in the future.

Distinct alterations of functional connectivity of the basal forebrain subregions in insomnia disorder

BACKGROUND

Cholinergic basal forebrain (BF) plays an important role in sleep-wake regulation and is implicated in cortical arousal and activation. However, less is known currently regarding the abnormal BF-related neuronal circuit in human patients with insomnia disorder (ID). In this study, we aimed to explore alterations of functional connectivity (FC) in subregions of the BF and the relationships between FC alterations and sleep and mood measures in ID.

MATERIALS AND METHODS

One hundred and two ID patients and ninety-six healthy controls (HC) were included in this study. Each subject underwent both resting-state fMRI and high-resolution anatomical scanning. All participants completed the sleep and mood questionnaires in ID patients. Voxel-based resting-state FC in each BF subregion (Ch_123 and Ch_4) were computed. For the voxel-wise FC differences between groups, a two-sample t-test was performed on the individual maps in a voxel-by-voxel manner. To examine linear relationships with sleep and mood measures, Pearson correlations were calculated between FC alterations and sleep and mood measures, respectively.

RESULTS

The ID group showed significantly decreased FC between the medial superior frontal gyrus and Ch_123 compared to HC. However, increased FC between the midbrain and Ch_4 was found in ID based on the voxel-wise analysis. The correlation analysis only revealed that the altered FC between the midbrain with Ch_4 was significantly negatively correlated with the self-rating anxiety scale.

CONCLUSION

Our findings of decreased FC between Ch_123 and medial superior frontal gyrus and increased FC between midbrain and Ch4 suggest distinct roles of subregions of BF underlying the neurobiology of ID.

The impact of cigarette smoking on the quality of sleep in Polish men

Quality of sleep directly impacts quality of life, whilst lifestyle significantly impacts night rest. Cigarette smoking is a serious threat to overall health, including sleep. Nicotine in cigarettes affects the nervous system, whilst the respiratory system is impacted by carcinogenic substances, such as dusts and tarred substances, inhaled with smoke. Cigarettes are assumed to be a risk factor in sleep disorders, including breathing sleep disorders.

This study’s aim was to analyze the impact of cigarette smoking on adult men’s polysomnographic parameters.

Polysomnographic records for 94 adult men were obtained from the polysomnography laboratory in Opolskie Province, Poland. Additionally co-morbidities, height, weight and frequency of smoking were also noted. Three groups of men were categorised according to the frequency with which they smoked: non-smokers, smoking less than a pack a day, smoking more than a pack a day.

Compared to non-smokers and mild smokers, men who were heavy smokers also exhibited the longest sleepless time (H=8.11; p=0.017), the maximum waking time following the onset of sleep (H=7.99; p= 0.018), the lowest sleep efficiency across the three groups (H=7.96; p=0.019), the greatest number of apnea events per hour of sleep (H=6.23; p= 0.045), the lowest Oxygen Level Nadir (H=11.44; p= 0.003) and the highest rate of limb movements per hour of sleep (H=9.81; p=0.007).

The dose effect was identified, which correlated more cigarettes men smoked per day with lower sleep quality.

A Research Domain Criteria (RDoC)-Guided Dashboard to Review Psilocybin Target Domains: A Systematic Review

BACKGROUND

Preliminary results from randomized controlled studies as well as identified molecular, cellular, and circuit targets of select psychedelics (e.g., psilocybin) suggest that their effects are transdiagnostic. In this review, we exploit the Research Domain Criteria (RDoC) transdiagnostic framework, to synthesize extant literature on psilocybin.

OBJECTIVE

We aimed to identify RDoC-based effects of psilocybin and vistas for future mechanistic and interventional research.

METHODS

A systematic search in electronic databases (i.e., PubMed, Scopus, PsycINFO, and Web of Science) performed in January and February 2021 identified English articles published between 1990 and 2020 reporting the effects of psilocybin on mental health measures. Data from included articles were retrieved and organized according to the RDoC bio-behavioral matrix and its constituent six main domains, namely: positive valence systems, negative valence systems, cognitive systems, social processes, sensorimotor systems, and arousal and regulatory systems.

RESULTS

The preponderance of research with psilocybin has differentially reported beneficial effects on positive valence systems, negative valence system, and social process domains. The data from the included studies support both short-term (23 assessments) and long-term (15 assessments) beneficial effects of psilocybin on the positive valence systems. While 12 of the extracted outcome measures suggest that psilocybin use is associated with increases in the "fear" construct of the negative valence systems domain, 19 findings show no significant effects on this construct, and seven parameters show lowered levels of the "sustained threat" construct in the long term. Thirty-four outcome measures revealed short-term alterations in the social systems' construct namely, "perception and understanding of self," and "social communications" as well as enhancements in "perception and understanding of others" and "affiliation and attachment". The majority of findings related to the cognitive systems' domain reported dyscognitive effects. There have been relatively few studies reporting outcomes of psilocybin on the remaining RDoC domains. Moreover, seven of the included studies suggest the transdiagnostic effects of psilocybin. The dashboard characterization of RDoC outcomes with psilocybin suggests beneficial effects in the measures of reward, threat, and arousal, as well as general social systems.

CONCLUSIONS

Psilocybin possesses a multi-domain effectiveness. The field would benefit from highly rigorous proof-of-mechanism research to assess the effects of psilocybin using the RDoC framework. The combined effect of psilocybin with psychosocial interventions with RDoC-based outcomes is a priority therapeutic vista.