Sleep timing, chronotype and social jetlag: Impact on cognitive abilities and psychiatric disorders

The Role of Timing and Amount of Outdoor Play in Emotional Dysregulation in Preschool Children

BACKGROUND

Currently, the time children spend playing outdoors is at an all-time low. However, the existing literature suggests that outdoor play may have cognitive and emotional benefits for children.

METHODS

The present study carried out a mediation analysis to explore whether amount and timing of outdoor play affects children's emotion regulation and whether working memory mediates these relations among 325 preschool children (Mage = 4.19, SD = 0.85) residing in a large Midwestern city in the United States.

RESULTS

Results showed that greater amounts of outdoor play very early (i.e., wake-up to noon) and very late (i.e., 6 PM to bedtime) in the day were related to greater emotional dysregulation. By contrast, greater amount of outdoor play from noon to 6 PM was related to lower emotional dysregulation. Importantly, the effect of amount of outdoor play from noon to 6 PM on emotion regulation was fully mediated by working memory.

CONCLUSION

The findings of the present study suggest that in early childhood outdoor play that supports children's circadian rhythms may have cognitive and, in turn, emotional benefits.

The Role of Chronotypes and Perceived Stress on Sleep Quality in Undergraduates in Taiwan

INTRODUCTION

Chronotypes and perceived stress can predict psychiatric symptoms and affect sleep quality, though the relationships between these factors are not completely described. This study explores the influence of chronotypes and perceived stress on sleep quality among undergraduates.

METHODS

An online survey was administered to a convenience sample of 110 undergraduates aged 18-23 years (mean age 20.32 ± 1.00) at a university in southern Taiwan, predominantly women and senior students. Three self-reporting instruments were used: the Munich Chronotype Questionnaire, the Perceived Stress Scale, and the Pittsburgh Sleep Quality Index. Multivariate regression analysis was performed to investigate the influence of chronotype and perceived stress on sleep quality in undergraduates.

RESULTS

Sixty-one per cent of the respondents were poor-quality sleepers. Moreover, 85.5% of the respondents were classified as "neither" chronotype, whereas 13.6% were "evening" chronotype. Sleep quality was associated with both chronotype and perceived stress level (r = 0.41, 0.43, p < 0.01). Multiple regression revealed higher MCTQ scores (continuous or categorical) and higher perceived stress were significantly associated with poorer sleep quality, explaining approximately 30% of the variance (p < 0.001).

CONCLUSIONS

The findings of this study showed evening-type undergraduates with higher perceived stress exhibited poorer sleep quality. Highlight the importance of considering chronotype in health promotion among individuals transitioning to adulthood. Early interventions may help align an individual's chronotype with their external time schedule, mitigate the negative impacts of misaligned later chronotypes, enhance sleep quality, and help to manage perceived stress levels in undergraduates.

Examining sex differences in morningness-eveningness and inter-individual variability across years of age: A cross-sectional study

This study investigated the impact of age on morningness-eveningness (ME) and its inter-individual variability, with a focus on sex-specific patterns. A sample of 2890 participants aged 12-94 years (55.85% female) completed the Composite Scale of Morningness. Multiple linear regression analyses revealed a significant Age × Sex interaction, indicating distinct age-dependent patterns for males and females in both ME and its inter-individual variability. We conducted segmented regression analyses to explore these dynamics further and identify breakpoints. Eveningness increased across adolescence, with both males and females reaching peak lateness at 20 years. Morningness increased thereafter until 64.94 years for females and until 59 years for males. Following these sex-specific breakpoints, morningness remained constant for females and increased at a reduced rate for males. After the age of 48, males exhibited greater morningness than females. Inter-individual variability in ME (VME) changed with age, increasing until 33 years for men and 36.80 years for women, followed by a decrease for both sexes. From 50.30 years onward, females showed greater VME compared to men. This study suggests that ME and VME shift across age, and differences between sexes were observed from middle age onwards. Diurnal preferences are likely influenced by internal and environmental variables.

Sleep patterns in adolescents and associations with substance use

OBJECTIVES

Good sleep during adolescence is crucial for maintaining physical and psychological health; however, sleep disturbance during this period may contribute to health risks, such as substance use. This study aimed to identify the latent sleep patterns across male and female adolescents, and their association with drug use.

METHOD

A cross-sectional study was conducted involving 1391 high school students (aged 15-17; 56.4% female). Participants completed the brief Pittsburgh Sleep Quality Index alongside other sleep measures, and the Timeline Follow-Back and Drug Use History Questionnaire to measure substance use. A multiple-group latent class analysis was used to identify sleep patterns across sexes, and pairwise Logistic Regression models to compare their association with substance use.

RESULTS

Four sleep patterns were identified with varying degrees of sleep difficulties: "Good Sleep" (43.3%), "Night Awakenings" (31.8%), "Poor Efficiency and Sleep Onset" (9.4%), and "Poor Sleep" (15.5%). Female adolescents were more likely to belong to Poor Sleep and Poor Efficiency and Sleep Onset patterns, and male adolescents to Good Sleep. Likewise, binge drinking and using alcohol for a longer period were associated with experiencing Poor Efficiency and Sleep Onset (OR=1.03 and 2.3, respectively); smoking tobacco within the past month was linked to Night Awakenings (OR=2.2); and using cannabis or illegal drugs to the Poor Sleep pattern (OR=2.4 and 2.6, respectively).

CONCLUSIONS

Varied sleep difficulties exist among adolescents that significantly correlate with different aspects of drug use. Targeted interventions that address both sleep and drug prevention are recommended.

Exploring the relationships between chronotypes, attachment styles, and mental health in flight attendants

Circadian rhythm-related individual differences such as chronotypes (morningness/eveningness) are associated with mental health though not elucidated in circadian-disrupted populations such as flight attendants. International flight attendants (n = 288) aged 21 to 55 (70.8% female, 76.4% white) completed an online survey assessing chronotypes, attachment, depression, and anxiety to investigate the associations between these variables. Results showed a prevalence of intermediate (41.6%) and evening types (40.6%). Evening chronotype was associated with and significantly predicted depression but not anxiety. Individuals who scored higher in attachment anxiety or avoidance had higher levels of depression and anxiety. Exploratory mediation showed that attachment avoidance partially mediated the relationship between anxiety and depression. Overall, chronotypes and attachment are implied as transdiagnostic factors for mental health outcomes and highlighted using a Chrono-Attachment Health Model. Further research is needed to confirm these findings among flight attendants and shift workers.

Circadian rhythms and objective measures of physical activity among middle-aged and older adults in Taiwan

BACKGROUND

To identify the association between daytime activity with objectively monitor and subjective variables at a different time-zone of day as well as the sex differences.

METHODS

Participants aged 50 years and older living in the community in Taiwan were recruited. The activity was measured by wearable actigraphy devices, diaries, and self-reported questionnaires. The study used nonparametric analysis to examine the association between mean activity level and demographic and subjective measurement variables.

RESULTS

Among the 55 participants enrolled in the study, data of 34 (62 %) participants who meet the criteria that wore a wearable actigraphy device for at least 7 completed days were analyzed. There is no significant relationship between each demographics and subjective measurement variables. However, actigraphy counts are significantly related to female's nutrition (Z = -2.367, p = 0.017*), and male's retirement status (Z = -2.132, p = 0.033*).

CONCLUSIONS

The activity in morning is highest of the day with significant correlation to evening activities. Moreover, actigraphy counts that indicating objective measure of physical activity in female is significantly related to physiological variables (nutritional status), while male are predicted by social variables (retired status).

[Screening for sleep disorders in internal medicine as potential comorbidities of systemic autoimmune diseases and improving patients' quality of life]

Sleep medicine and internal medicine share a global and transdisciplinary vision of human physiology and illnesses, with an approach guided by the complaint and semiology. In France, approximately 13 to 18 million individuals suffer from a sleep disorder: these disorders therefore represent a public health problem. Their comorbidities with systemic autoimmune diseases are frequent. As such, this article suggests an approach to screening for sleep disorders in daily clinical practice of internal medicine leading, when appropriate, to request specialized diagnostic and/or therapeutic care in sleep medicine to substantially improve patients' quality of life.

The effect of alcohol on subsequent sleep in healthy adults: A systematic review and meta-analysis

Alcohol is commonly consumed prior to bedtime with the belief that it facilitates sleep. This systematic review and meta-analysis investigated the impact of alcohol on the characteristics of night-time sleep, with the intent to identify the influence of the dose and timing of alcohol intake. A systematic search of the literature identified 27 studies for inclusion in the analysis. Changes in sleep architecture were observed, including a delay in the onset of rapid eye movement (REM) sleep and a reduction in the duration of REM sleep. A dose-response relationship was identified such that disruptions to REM sleep occurred following consumption of a low dose of alcohol (≤0.50 g∙kg-1 or approximately two standard drinks) and progressively worsened with increasing doses of alcohol. Reductions in sleep onset latency and latency to deep sleep (i.e., non-rapid eye movement stage three (N3)) were only observed following the consumption of a high dose of alcohol (≥0.85∙g kg-1 or approximately five standard drinks). The effect of alcohol on the remaining characteristics of sleep could not be determined, with large uncertainty observed in the effect on total sleep time, sleep efficiency, and wake after sleep onset. The results of the present study suggest that a low dose of alcohol will negatively impact (i.e., reduce) REM sleep. It appears that high doses of alcohol may shorten sleep onset latency, however this likely exacerbates subsequent REM sleep disruption. Future work on personal and environmental factors that affect alcohol metabolism, and any differential effects of alcohol due to sex is encouraged.

Prevalence of social jetlag and associated factors in Brazilian adolescents: Results from a country-wide cross-sectional study

OBJECTIVES

Social jetlag is a disturbance in the circadian rhythm caused by a desynchronization between an individual's biological rhythm and social commitments and responsibilities. It leads to sleep debt during the week and compensation on weekends. Social jetlag is associated with an increased risk of chronic diseases and cognitive dysfunction in adolescents. This study aims to assess the prevalence of social jetlag and associated factors in Brazilian adolescents.

METHODS

Adolescents of both sexes, aged between 12 and 17years, participating in the Study of Cardiovascular Risks in Adolescents (ERICA), were included. The sleep duration on a typical weekday and weekend day was collected through a self-reported questionnaire. The occurrence of social jetlag was defined as the difference between the midpoint of sleep on weekends and weekdays, with differences equal to or higher than 1hour considered as an indicator of positive social jetlag. Factors associated with the prevalence of social jetlag were investigated using Poisson regression models.

RESULTS

The sample included a total of 64,029 adolescents. Social jetlag affects more than 80% of Brazilian adolescents, with higher prevalence among girls in the age group of 16-17years, with white skin color, attending private schools, and those having morning classes. Additionally, unhealthy risk behaviors such as skipping breakfast, alcohol consumption, and increased screen time are associated with a higher prevalence of social jetlag.

CONCLUSION

The prevalence of social jetlag was high in Brazilian adolescents, and, among its associated factors, studying in the morning shift and engaging in unhealthy risk behaviors stand out.

Association between screen time, homework and reading duration, sleep duration, social jetlag and mental health among Chinese children and adolescents

OBJECTIVES

To examine the associations of screen time, homework and reading duration, sleep duration, social jetlag with mental health in children and adolescents, as well as its gender differences.

METHODS

From December 2023 to April 2024, a total of 62 395 children and adolescents were selected from 51 schools in 17 cities of China by stratified cluster sampling. Screen time, homework and reading duration, sleep duration, and social jetlag were calculated by answering the questions about watching TV time, playing smartphones time, doing homework time, reading extracurricular books time, bedtime, wake-up time, and nap time during weekdays and weekends. Mental health was assessed by the Revised Mental Health Inventory-5 (MHI-5). The generalized linear model was used to determine the association between screen time, homework and reading duration, sleep duration, social jetlag, and mental health in children and adolescents.

RESULTS

The generalized linear model results showed that longer watching TV time, longer playing smartphones time, longer homework time, and greater social jetlag were correlated with poorer mental health in children and adolescents, while longer nighttime sleep duration, and longer daytime nap duration were correlated with better mental health. Moreover, in primary school and junior high school, we found that this association was stronger during the weekdays. However, in senior high school, this association was stronger during the weekends. After according to gender stratified, we found that the strength of this association was different in boys and girls at different study phases. Furthermore, our findings also revealed a significant quadratic relationship, indicating the association of better mental health with an optimal amount of sleep duration.

CONCLUSIONS

There was a significant association between screen time, homework and reading duration, sleep duration, social jetlag, and mental health in children and adolescents. This study has the potential to offer useful insights for the prevention and control of mental health issues in children and adolescents.

Using actigraphy to assess chronotype: Simpler is better

Actigraphy provides a unique method for objectively measuring sleep activity patterns, but confusion remains about how to use actigraphy data to determine chronotype. To determine the most suitable parameter, this study made a systematic comparison of actigraphy-derived parameters: the average midpoint of sleep of all record days (aMS-acti), cosine parameter (Bathyphase), and non-parametric parameter (L5-mid) in terms of the consistency with subjective chronotype parameters, test-retest reliability, and external validity. More importantly, we proposed multiple Munich Chronotype Questionnaire (MCTQ)-based actigraphy parameters: considering the difference between weekday (MSW-acti) with weekends (MSF-acti) and the sleep debt (MSFsc-acti). The study collected 5 days of actigraphy and scale data from 1,055 young adults, 138 of whom participated in the retest 2 years later. The results showed that, in terms of consistency with subjective chronotype, aMS-acti generally performed better than other actigraphy parameters. In addition, aMS-acti had the highest test-retest reliability and was more closely related to the Pittsburgh Sleep Quality Index (PSQI), Insomnia Severity Index (ISI), and Self-Rating Depression Scale (SDS). The results suggest that the simplest parameter (aMS-acti) is superior to traditional cosine and non-parametric parameters and MCTQ-derived parameters for short-term assessment of chronotype.

Associations Among Social Jet Lag, Sleep-Related Characteristics, and Burnout of Nurses in Tertiary Hospitals

To investigate the status of social jet lag (SJL) through sociodemographic factors among clinical nurses and examine the correlation with burnout. There has been relatively little research on the possible factors resulting in SJL among nurses in China and its role in burnout. A multicenter cross-sectional study recruited 596 nurses from 7 Chinese hospitals. Online questionnaires were delivered to assess sociodemographics, shift work, SJL, chronotypes, and the burnout of nurses. Nurses had severe levels of SJL. The number of children, forms of employment, specialty area, length of professional service, and chronotypes were the main predictors of SJL. Moreover, SJL affected burnout (emotional exhaustion and deindividuation), and reducing the nurses' SJL could relieve their burnout. Additional evidence-based interventions indicate that reducing the SJL is essential as the nurses are suffering severe job burnout.

The interplay among sleep patterns, social habits, and environmental cues: insights from the Spanish population and implications for aligning daily rhythms

Introduction

The interplay among sleep patterns, social habits and environmental cues is becoming increasingly more important for public health and wellbeing due to its connection to circadian desynchronization. This paper explores said connections in Spain (which has an official and solar time mismatch), introducing the "Three Times Score" ‒which is based on questions widely used in the field‒ as a complementary tool for exploring the interplay of daily rhythms.

Methods

The questionnaire covers sleep-related habits, social time, and environmental time. The study includes 9,947 participants (34.89 ± 12.15 y/o, mean ± SD; 5,561 women) from different Spanish regions. Sleep parameters were obtained for work and free days, as well as a modified version of the sleep-corrected midsleep on free days (MBFbc) and a parameter similar to social jet lag, both derived from bed time rather than sleep time. A number of indexes were computed to compare bed and work-related habits, together with natural light/dark cycle, along with the Three Times Score. Mixed-effect regression analysis was used to test whether the biological, social and environmental factors included in the study significantly predicted the sleep-related parameters: bedtime, wake-up time, time in bed and mid-bedtime.

Results and discussion

Temporal differences were found between work and free days, with waking-up occurring 2 h earlier on work days (7:10 ± 0:01) than on free days (9:15 ± 0:01). Bed times were 1 h earlier on work days (23:46 ± 0:01) than on free days (00:45 ± 0:01), whereas time in bed was over 1 h shorter on work (7 h 23 min) versus free (8 h 29 min) days. Strong correlations were found between work starting time and waking-up and bedtimes on workdays. Women went to bed earlier and woke up later, spending more time in bed. Differences in sleep habits were observed between work and free days across all age groups. The group of younger adults (18-30) reported going to bed later than older and younger groups, especially on free days. Adolescents and young adults also woke-up later than other age groups, especially on free days. Social jet lag (relative to bed time) and desynchronization indexes also varied with age, with younger adult participants exhibiting higher levels. Seasonal differences were limited, with minor variations between winter and summer. According to the multiple regression analysis, social (day type, work start time, alarm clock usage), biological (age, gender, in most cases related to sex) and environmental (sunset time) factors significantly contribute to predicting sleep/bed related schedules. This study provides insights into sleep habits in the Spanish population, introducing the Three Times Score as a complementary tool for exploring the interactions between sleep/bed-related habits, natural darkness and work-related schedules. Understanding this interplay is crucial for developing tailored interventions to improve sleep and wellbeing.

How Late Nights Influence Brain Cortical Structures: Distinct Neuroanatomical Measures Associated With Late Chronotype in Young Adults

Chronotype is an inherent physiological trait reflecting an individual's subjective preference for their sleep awakening time, exerting a substantial influence on both physical and mental well-being. While existing research has established a close relationship between chronotype and individual brain structure, prior studies have predominantly focused on individual measurements of brain structural scales, thereby limiting the exploration of the underlying mechanisms of structural changes. This study seeks to validate previous research findings and enhance our understanding of the correlation between circadian rhythm preference and diverse cortical indicators in healthy young individuals. Magnetic resonance imaging (MRI) scans and chronotype assessments were conducted once for all participants, comprising 49 late chronotype (LC) young adults and 49 matched early chronotype young adults. The Chronotype Questionnaire was utilized to assess morningness and eveningness preferences. Surface-based analysis of structural MRI data revealed that LC young adults exhibited thinner cortical thickness of left pars orbitalis and lower cortical mean curve of right paracentral gyrus. Overall, this study represents a significant advancement in elucidating the connection between brain structure and function within the context of chronotypes.

Nutraceutical composition (yeast β-glucan, prebiotics, minerals, and silymarin) predicts improvement of sleep quality and metabolic parameters: A randomized pilot study

BACKGROUND & AIMS

The search for integrative and natural therapies that favor homeostasis to boost sleep and diet quality took place for young adult populations as a non-pharmacological strategy for long-term good quality of life. Thus, the present pilot study aims to investigate the effects of 90-day consumption of a nutraceutical composition on the neuro-immune-endocrine axis, providing better sleep quality and health improvement.

METHODS

For this, from March 2021 to June 2021, twenty-two Brazilian young adult volunteers (women and men) with BMI between 18.5 and 34.9 kg/m2 were divided into three distinct supplementation groups: NSupple; NSupple plus_S, and NSupple plus. Briefly, the supplement compositions included yeast β-glucan, prebiotics, and minerals in different concentrations associated or not with the herbal medicine silymarin. Neither nutritional nor physical activity interventions were performed during this pilot study period. The anthropometrics measures, questionnaires answer data, and harvest blood for metabolic, inflammatory, and hormonal tests were collected at baseline time (day zero-T0) and day 90 (T90) post-supplementation.

RESULTS

Our results highlight that the supplementation reduced body mass index (BMI), Waist-to-height ratio (WHtR), waist circumference, AST/ALT ratio, alkaline phosphatase, and HbA1c. Post-supplementation the IL-6 and IL-10 levels and the sleep, humor, and quality of life scores were suggested to improve. Sleep quality improvement seems to predict the reduction of adiposity-related body measures.

CONCLUSION

In sum, the nutraceutical supplementation might be related to anthropometric, metabolic, and endocrine parameters after 90 days reflecting on perception of humor, sleep, and life quality enhancement. However, it is important to recognize the limitation of the data presented considering that this was a pilot study.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, identifier NCT04810572 registered on 20th February 2021.

The association between chronotype profile and temporomandibular disorders among college students

BACKGROUND

Temporomandibular joint disorders (TMDs) are common in young adults, and the link between chronotype profile and TMDs is unclear.

OBJECTIVE

This study examined TMD prevalence and chronotype distribution and explored the relationship between chronotype and TMDs in young adults.

MATERIALS AND METHODS

A total of 663 students from Sichuan University completed questionnaires. Chronotype profiles were assessed using the Morningness-Eveningness Questionnaire, and TMDs were screened using the Fonseca Memory Index. To validate the findings, 68 TMD patients and 136 controls were enrolled.

RESULTS

The prevalence of TMDs was 69.7%, with significant differences among chronotype profiles. The intermediate profile was the most common chronotype. Eveningness profile was associated with higher TMDs prevalence and severity. Muscle pain and side movement difficulty scores were higher in eveningness and intermediate profiles. Female gender (OR 2.345; 95% CI 1.668-3.297) was a TMD risk factor, while morningness profile (OR 0.537; 95% CI 0.297-0.970) was protective. Validation with TMD patients and controls supported these findings, showing higher eveningness profile prevalence in the TMD groups.

CONCLUSIONS

TMDs have a high prevalence in college students, chronotype profiles shown to be associated with TMDs. Morningness is the protection factor in TMDs and PT, eveningness is a risk factor for IT.

The association between salivary IL-6 and poor sleep quality assessed using Apple watches in stressed workers in Japan

Insomnia is a major concern among stressed workers worldwide. Although stress generally has a detrimental effect on sleep quality, the impact of biological stress, especially the immunological stress response, on sleep quality is not yet fully understood. Stressed workers were recruited through a screening process using a Brief Job Stress Questionnaire. The participants were asked to complete various occupation-related questionnaires. Additionally, saliva samples were collected to assess interleukin-6 (IL-6) levels as an immunological stress response. Subsequently, they were asked to wear an Apple Watch to record their sleep pattern for one week. Their sleep architecture was estimated using a previously published and validated method. Finally, data from 73 participants were analyzed. Our multivariable analysis revealed that shorter durations of slow-wave sleep (non-rapid eye movement sleep stage 3) were significantly associated with elevated IL-6 levels (p = 0.005) and greater daytime sleepiness (p = 0.002) after controlling for total sleep time. Our finding that a higher immunological stress response is associated with poor sleep quality contributes to a better understanding of insomnia in stressed workers and emphasizes the importance of stress management in this population.

Early morning hour and evening usage habits increase misinformation-spread

Social media manipulation poses a significant threat to cognitive autonomy and unbiased opinion formation. Prior literature explored the relationship between online activity and emotional state, cognitive resources, sunlight and weather. However, a limited understanding exists regarding the role of time of day in content spread and the impact of user activity patterns on susceptibility to mis- and disinformation. This work uncovers a strong correlation between user activity time patterns and the tendency to spread potentially disinformative content. Through quantitative analysis of Twitter (now X) data, we examine how user activity throughout the day aligns with diurnal behavioural archetypes. Evening types exhibit a significantly higher inclination towards spreading potentially disinformative content, which is more likely at night-time. This knowledge can become crucial for developing targeted interventions and strategies that mitigate misinformation spread by addressing vulnerable periods and user groups more susceptible to manipulation.

Association between Life's Essential 8 and cognitive function among older adults in the United States

The American Heart Association (AHA) recently redefined cardiovascular health (CVH) with the introduction of Life's Essential 8 (LE8), which encompasses eight areas (diet, physical activity, nicotine exposure, sleep duration body mass index, non-HDL cholesterol, blood glucose, and blood pressure). This study aimed to explore the relationships between both the aggregate and individual CVH metrics, as defined by Life's Essential 8, and cognitive function in older adults in the United States. This cross-sectional, population-based study analyzed data from the National Health and Nutrition Examination Survey conducted between 2011 and 2014, focusing on individuals aged 60 years and older. CVH was categorized as low (0-49), moderate (50-79), or high (80-100). Cognitive function was assessed through the CERAD tests, Animal Fluency test, and Digit Symbol Substitution test. Multivariable logistic models and restricted cubic spline models were employed to investigate these associations. This study included a total of 2279 older adults in the United States. Only 11% of adults achieved a high total CVH score, while 12% had a low score. After further adjustment for potential confounding factors, higher LE8 scores were significantly associated with higher scores on CERAD: delayed recall score (0.02[0.01, 0.03]; P < 0.001), CERAD: total score (3 recall trials) (0.04[0.02, 0.06]; P < 0.001), animal fluency: total score (0.09[0.05, 0.12]; P < 0.001), and digit symbol: score (0.29[0.18, 0.41]; P < 0.001), demonstrating a linear dose-response relationship. Similar patterns were also observed in the associations between health behavior and health factor scores with cognitive function tests. LE8 scores exhibited positive linear associations with cognitive function. Maintaining better levels of CVH may be associated with higher levels of cognitive function in older Americans, but further research is needed to confirm the causal and temporal relationships between LE8 and cognitive function.

Association between cognitive insight and anxiety among community-dwelling schizophrenia patients: the chain mediating effects of family cohesion and chronotype

Objective

To investigate the effect of cognitive insight on anxiety in community-dwelling schizophrenia patients and to construct a chain mediating model to determine the underlying mechanisms of the relationship between cognitive insight and anxiety through family cohesion and chronotype.

Methods

The Beck Cognitive Insight Scale, the Chinese version of the Family Adaptability and Cohesion Scale, the Morningness-Eveningness Scale, and the Generalized Anxiety Disorder Scale were used to assess cognitive insight, family cohesion, chronotype, and anxiety in a sample of 785 individuals with schizophrenia living in the community. Spearman correlation analysis, multiple linear regression and Bootstrap methods were employed to analyze the four variables.

Results

Residential region, current employment status, and family economic status impacted anxiety among community-dwelling schizophrenia patients. All variables were associated with each other, but self-certainty was not significantly associated with anxiety. Cognitive insight and self-reflection had direct effects on anxiety, as well as indirect effects on anxiety through the partial mediating effect of chronotype, the suppressing effect of family cohesion, and the chain mediating effect of family cohesion and chronotype.

Conclusions

Family cohesion and chronotype can mediate the relationship between cognitive insight and anxiety. Improving family functioning, promoting emotional relationships within families, and correcting non-circadian sleep patterns can reduce anxiety in community-dwelling schizophrenia patients, with important implications for improving adverse mental health outcomes.

Association of sleep and generalized anxiety disorder in Korean adolescents

BACKGROUND

Generalized anxiety disorder (GAD) is a common anxiety disorder among adolescents, significantly impacting their concentration and learning capabilities. The connection between emotional well-being and sleep is well-established, and Korean adolescents are particularly prone to inadequate sleep. This study aimed to determine the association between sleep duration and GAD in Korean adolescents.

METHODS

This study was conducted using data from 106,513 adolescents aged 12-18 years. Data from the 2020-2022 Korea Youth Risk Behavior Survey were used. Sleep duration was classified into five groups, based on an average sleep duration of 7-7.9 h in adolescents. Social jet lag was defined as a misalignment between an individual's biological and social clocks. Differences in sleep duration between weekdays and weekends, social jet lag, and bedtime were each classified into three categories. Multiple logistic regression analysis was performed to evaluate the association between sleep duration and GAD.

RESULTS

Comparing the five groups classified based on sleep duration, adolescents in the groups that slept less experienced a significant increase in the odds of developing GAD (adjusted odds ratio [aOR]: boys: 1.10 in the 6.0-6.9-h group, 1.14 in the 5.0-5.9-h group, and 1.23 in the ≤ 4.9-h group; girls: 1.05 in the 6.0-6.9-h group, 1.19 in the 5.0-5.9-h group, 1.22 in the ≤ 4.9-h group). Adolescents with poor sleep quality experienced more frequent instances of inadequate sleep (aOR: boys: 2.51; girls: 2.43).

CONCLUSIONS

GAD is strongly associated with insufficient sleep. Consequently, it is imperative to assess and address GAD in adolescents with irregular sleep patterns.

Frontoparietal Response to Working Memory Load Mediates the Association between Sleep Duration and Cognitive Function in Children

Lack of sleep has been found to be associated with cognitive impairment in children, yet the neural mechanism underlying this relationship remains poorly understood. To address this issue, this study utilized the data from the Adolescent Brain Cognitive Development (ABCD) study (n = 4930, aged 9-10), involving their sleep assessments, cognitive measures, and functional magnetic resonance imaging (fMRI) during an emotional n-back task. Using partial correlations analysis, we found that the out-of-scanner cognitive performance was positively correlated with sleep duration. Additionally, the activation of regions of interest (ROIs) in frontal and parietal cortices for the 2-back versus 0-back contrast was positively correlated with both sleep duration and cognitive performance. Mediation analysis revealed that this activation significantly mediated the relationship between sleep duration and cognitive function at both individual ROI level and network level. After performing analyses separately for different sexes, it was revealed that the mediation effect of the task-related activation was present in girls (n = 2546). These findings suggest that short sleep duration may lead to deficit in cognitive function of children, particularly in girls, through the modulation of frontoparietal activation during working memory load.

Chronotype and emotion processing: a pilot study testing timing of online cognitive bias modification training

BACKGROUND

Circadian rhythms influence cognitive performance which peaks in the morning for early chronotypes and evening for late chronotypes. It is unknown whether cognitive interventions are susceptible to such synchrony effects and could be optimised at certain times-of-day.

OBJECTIVE

A pilot study testing whether the effectiveness of cognitive bias modification (CBM) for facial emotion processing was improved when delivered at a time-of-day that was synchronised to chronotype.

METHODS

173 healthy young adults (aged 18-25) with an early or late chronotype completed one online session of CBM training in either the morning (06:00 hours to 10:00 hours) or evening (18:00 hours to 22:00 hours).

FINDINGS

Moderate evidence that participants learnt better (higher post-training balance point) when they completed CBM training in the synchronous (evening for late chronotypes, morning for early chronotypes) compared with asynchronous (morning for late chronotypes, evening for early chronotypes) condition, controlling for pre-training balance point, sleep quality and negative affect. There was also a group×condition interaction where late chronotypes learnt faster and more effectively in synchronous versus asynchronous conditions.

CONCLUSIONS

Preliminary evidence that synchrony effects apply to this psychological intervention. Tailoring the delivery timing of CBM training to chronotype may optimise its effectiveness. This may be particularly important for late chronotypes who were less able to adapt to non-optimal times-of-day, possibly because they experience more social jetlag.

CLINICAL IMPLICATIONS

To consider delivery timing of CBM training when administering to early and late chronotypes. This may generalise to other psychological interventions and be relevant for online interventions where the timing can be flexible.

Validation of the French version of the Munich ChronoType questionnaire and associations between chronotype and physiological parameters

Assessing chronotype is essential in clinical and research environments, but the Munich ChronoType Questionnaire (MCTQ), a widely utilised tool, is not available in French. Therefore, we carried out an observational monocentric study to validate the French MCTQ against the sleep diary for sleep schedules, the Morningness-Eveningness Questionnaire (MEQ) for chronotype, and polysomnography measures. We utilised the mid-sleep point on free days (MSF), adjusted for sleep debt (MSFsc), to gauge morningness/eveningness. The study included 80 participants (average age: 40.9 years, 50% female). The sleep schedules determined by the MCTQ and the sleep diary showed a high correlation. The MSFsc demonstrated a significant correlation with the MEQ, persisting even under sleep constraints such as an alarm on free days. The predictive accuracy was strong for a morning chronotype and moderate for an evening chronotype as assessed using the MEQ. In summary, the French MCTQ is a reliable tool for researchers and clinicians for assessing sleep schedules and chronotype in French-speaking populations. The MSFsc can effectively predict chronotype, even under sleep constraints. However, for the evening chronotype, self-assessment appears to be more accurate. The association with polysomnography measures enriches our understanding of the chronotype at the intersection of behaviour and physiology.

Study on the circadian rhythm and sleep state characteristics of patients with acute cerebral infarction accompanied by sleep-breathing disorders

There is limited research on the circadian rhythm and sleep state in patients with acute cerebral infarction (ACI) accompanied by sleep-breathing disorders (SDB). This study aims to provide a scientific basis for individualized diagnosis and treatment for stroke-related SDB patients. The SC-500 sleep monitor was used to continuously monitor 1367 ACI patients over 5 days. Based on the apnea-hypopnea index (AHI), patients were divided into non-SDB group (normal) and SDB group (mild, moderate, severe, fluctuating). Interdaily stability (IS) and intradaily variability (IV) were calculated through heart rate monitoring, and sleep states and their correlations were analyzed. Compared to the non-SDB group, patients with moderate-to-severe ACI accompanied by SDB showed decreased IS, increased IV, and sleep fragmentation. Significant statistical differences were observed in total sleep time (TST), rapid eye movement latency (REML), sleep efficiency (SE), non-rapid eye movement stages 1-2 (NREM stages1-2), non-rapid eye movement stages 3-4 (NREM stages 3-4), proportion of non-rapid eye movement (NREM%), wake after sleep onset (WASO), and number of awakenings (NOA) between the SDB group and the non-SDB group (P < 0.05). AHI showed a strong negative correlation with IS and a strong positive correlation with IV. AHI was positively correlated with sleep latency (SL), REML, NREM stages1-2, NREM%, proportion of rapid eye movement (REM%), WASO, time out of bed (TOB), and NOA, and negatively correlated with TST, SE, NREM stages 3-4, and rapid eye movement (REM), all with statistical significance (P < 0.05). There were significant statistical differences in the Mini-Mental State Examination (MMSE) between patients with and without SDB, and among mild, moderate, severe, and fluctuating groups (P < 0.05). Patients with moderate-to-severe ACI accompanied by SDB are more likely to experience changes in circadian rhythm and sleep states, which in turn affect cognitive functions.

Supplementary Information

The online version contains supplementary material available at 10.1007/s41105-024-00516-1.

Prevalence, correlates, and mental health outcomes of social jetlag in Chinese school-age adolescents: A large-scale population-based study

BACKGROUND

This cross-sectional study aimed to examine the prevalence and correlates of social jetlag (SJL) in Chinese adolescents, as well as to test the relationships between SJL and mental health problems.

METHODS

A total of 106979 students (Mage = 13.0 ± 1.8 years; Nmale = 58296 [54.5 %]) from Shenzhen, China completed an online survey from May 24th to June 5th, 2022. Information on sociodemographics, lifestyles, sleep characteristics, anxiety symptoms, and depressive symptoms was collected by a self-administered questionnaire. Multivariate and binary logistic regression were adopted for data analysis.

RESULTS

17.8 % of participants experienced SJL ≥ 2 h. To adjust the accumulated sleep debt, sleep-corrected SJL (SJLsc) was calculated and 8.3 % of individuals self-reported SJLsc ≥ 2 h. Both SJL and SJLsc show an increasing trend with age. Risk factors of SJL included females, poor parental marital status, being overweight, physically inactive, smoking, drinking, and having a late chronotype. Moreover, males, having siblings, boarding at school, short sleep duration, experiencing insomnia, and frequent nightmares were significantly associated with an increased risk of SJLsc. After adjusting for all covariates, adolescents with SJLsc ≥ 2 h were more likely to have anxiety symptoms (OR: 1.35, 95 % CI: 1.24-1.48) and depressive symptoms (OR: 1.35, 95 % CI: 1.25-1.46) than those with SJLsc < 1 h.

CONCLUSIONS

SJL is common among Chinese school-age adolescents. This study is valuable for the development of prevention and intervention strategies for SJL in adolescents at the population level. Additionally, the strong links between SJLsc and emotional problems underscore the critical significance of addressing SJL as a key aspect of adolescent well-being.

Why circadian rhythmicity matters: Associations between sleep irregularity and mental health conditions during the Covid-19 health crisis

OBJECTIVE

To assess the association between sleep irregularity, anxiety, and depression while controlling for other sleep dimensions and using a longitudinal design.

METHODS

Longitudinal cohort study which started in April 2020 during the first French lockdown in the general population. Follow-up questionnaires were completed in June 2020, a period without lockdown measures. Participants were asked about their sleep (regularity, duration, timing, complaints) and their anxiety (General Anxiety Disorder-7) and depressive (Patient Health Questionnaire-9) symptoms.

RESULTS

A total of 3745 participants were included (mean age: 28.9 years) with 2945 women (78.6%). At baseline, 38.1% (1428) of participants reported irregular sleep timing, 23.8% (891) anxiety and 28.9% (1081) depressive symptoms. In cross-sectional analyses, irregular sleep timing was associated with a 2.5-fold higher likelihood of anxiety and a 4-fold higher likelihood of depressive symptoms compared to regular sleepers. Associations were not explained by the other sleep dimensions and persisted in a longitudinal analysis, with irregular sleep timing at baseline being associated with anxiety (OR = 3.27[1.58-6.76]) and depressive symptoms (OR = 3.45[1.66-7.19]) during follow-up.

CONCLUSION

The results show a strong association between sleep irregularity and mental health. Furthers studies are needed to explore how sleep regularity could promote good mental health in non-clinical populations.

Sleep quality mediates the association between chronotype and mental health in young Indian adults

There is increasing recognition of 'higher preference for eveningness' as a potential independent risk factor for poor mental health. To examine the chronotype-mental health relationship while also quantifying the potential roles of poor sleep quality, relevant personality traits, and childhood trauma, we assessed 282 young adults (18-40 years; 195 females) residing in North India, between January and March 2023 (to control for seasonal variation), using self-report measures of diurnal preference, sleep patterns, mental health (depression, anxiety, and stress), personality traits (extraversion, neuroticism, schizotypy, and impulsivity), and childhood trauma. The results showed a significant association between eveningness and poor mental health but this association was fully mediated by poor sleep quality. Neuroticism, emotional abuse and cognitive disorganisation were correlated with eveningness as well as with poor mental health and sleep quality. Neuroticism and emotional abuse, but not cognitive disorganisation, also had indirect effects on mental health via sleep quality. Our findings highlight the crucial role played by sleep quality in the chronotype-mental health relationship.

Association between dinner-bedtime interval and type 2 diabetes mellitus: a large-scale cross-sectional study

Objective

Glucose metabolism is impacted by circadian disruption. Dinner-bedtime interval (DBI) was an accessible indicator to reflect the alignment between dinner time and circadian clock. We aimed to investigate the association of DBI with type 2 diabetes mellitus (T2DM).

Methods

7676 adult subjects from the Henan Rural Cohort were included. Their demographic information including dinner time and bedtime was collected. Fasting venous blood samples were collected for biochemical determinations. Generalized linear regression model was used to analyze the factors influencing DBI. Furthermore, logistic regression incorporated with restricted cubic spline model was applied to evaluate the association between DBI and T2DM.

Results

The results of multiple linear regression model showed that age (β: -0.018, 95% CI: -0.021, -0.015) was negatively correlated with DBI. Female (β: 0.311, 95% CI: 0.229, 0.393), junior high school education (β: 0.246, 95% CI: 0.187, 0.306), high school education or above (β: 0.346, 95% CI: 0.259, 0.433), average monthly income with 1000-1999 CNY(0.102, 95% CI: 0.032, 0.171), average monthly income ≥ 2000 CNY (β: 0.164, 95% CI: 0.076, 0.251), moderate physical activity (β: 0.134, 95% CI: 0.071, 0.197), current smokers (β: 0.214, 95% CI: 0.118, 0.309), current drinkers (β: 0.099, 95% CI: 0.008, 0.190) were positively correlated with DBI. Furthermore, DBI was significantly associated with T2DM (adjusted OR: 0.910, 95%CI: 0.845-0.979, P = 0.012). DBI longer than 3 h was associated with decreased risk of T2DM (adjusted OR: 0.773, 95%CI: 0.648-0.921, P = 0.004).

Conclusions

DBI larger than 3 h is beneficial to T2DM prevention. Further investigation is required to verify the association.

Sleep patterns in Metropolitan and Regional areas in Japan: Before and during COVID-19 social restrictions

Sleep timing is an important output of the circadian system. The COVID-19-mandated social restrictions significantly altered commuting time and sleep duration regionally in Japan. This study aimed to elucidate sleep patterns, especially chronotype and social jetlag (SJL), due to changes in social time pressure through the social restrictions between the Metropolitan and Regional areas in Japan. As part of the Global Chrono Corona Survey 2020 (GCCS), the data were collected during social restrictions (SR), but pre-COVID-19 behaviours were also queried retrospectively. We analyzed a cohort of 729 respondents representing both the Metropolitan and the Regional areas separately for workdays and work-free days. While the areas showed no difference in SJL before SR, the differential decrease was larger in the Metropolitan area during SR, resulting in a significant difference in SJL between the areas. The outdoor light exposure before SR was 30 min longer in the Metropolitan areas than in the Regional; during SR both areas showed similarly low (below 1 h) outdoor light exposures. The variables associated with decreased SJL were the Metropolitan areas, work-from-home, a no-usage alarm clock on workdays, and chronotypes (mid-sleep time on free days corrected for sleep deficit accumulated over the workweek, MSFsc) during SR. The results suggest that relaxed social schedules, as reflected in the increased frequency of work-from-home and reduced alarm clock use, and moving towards earlier MSFsc during SR were linked to decreased SJL and were more prominent in the Metropolitan areas. This study provides insights into sleep patterns and the social time pressure markers, by comparison between residential groups in Japan.

Associations between multiple sleep dimensions and suicide and non-suicidal self-injury: a cross-sectional study of 3828 Chinese young people

PURPOSE

Suicide and non-suicidal self-injury (NSSI) are preventable concerns in young people. Suicidal ideation (SI), suicidal plans (SP) and suicidal attempt (SA) are closely related to death. Sleep problems are known risk factors for suicide and NSSI. This study aimed to explore the relationship between sleep, suicidality and NSSI.

METHODS

Participants were 3,828 middle school and college students aged 11-23 years from urban and rural areas of Henan Province. Sleep, suicidal phenomena and NSSI were assessed by applying self-reported questionnaires. Chi-squared tests were utilized to demonstrate the demographic data and sleep variables. The correlation between sleep, suicidality and NSSI were explored by using binary logistic regression, while adjusting socio-demographic characteristics with multivariate models.

RESULTS

Sleep variables except mid-sleep time were related to suicidal phenomena (P < 0.05). Greater social jet lag (SJL) [≥ 2 h (h)] was associated with increased risk of SI [Odds ratios (OR) = 1.72, 95% confidence intervals (CI):1.40-2.11], SP (OR = 2.10, 95%CI:1.59-2.79) and SA (OR = 1.50, 95%CI:1.00-2.26). Non-only child participants with SJL (≥ 2 h) had significantly increased odds of SI (OR = 1.75, 95%CI: 1.41-2.18) and SP (OR = 2.25, 95%CI: 1.66-3.05). Eveningness chronotype had the strongest correlation with SI (OR = 3.87, 95%CI:2.78-5.38), SP (OR = 4.72, 95%CI:2.97-7.50), SA (OR = 6.69, 95%CI:3.08-14.52) and NSSI (OR = 1.39, 95%CI:1.02-1.90).

CONCLUSION

Overlong or short sleep duration, SJL, eveningness chronotype and other sleep abnormalities (e.g., daytime dysfunction, low sleep efficiency) were associated with a higher prevalence of SI, SP and SA. Additionally, eveningness was significantly correlated with NSSI among young people. These findings suggested the importance of assessing and intervening in sleep habits to prevent suicide and NSSI in young people.

Depression, Anxiety and Poor Sleep Quality are Associated with Chronotype and Financial Wellness in University Students

Background: Evidence suggests the importance of a person's chronotype in predicting various aspects of an individual's physical and mental health. While the effect of depression on sleep is well established, the impact of a person's specific sleep timing and chronotype on the prevalence of both depression and anxiety has yet to be fully understood, especially among university students, vulnerable to mental health problems. In addition, other factors also seem to influence the occurrence of depression and anxiety among students as well as their quality of sleep, one of which being the students' financial wellness. The objective was to evaluate the association between chronotype and the severity and prevalence of depression among Lebanese university students, while also taking into account the possible connection between chronotype and financial wellness and both anxiety and sleep quality. Methods: This cross-sectional study was conducted between December 2021 and February 2022; 330 Lebanese university students was included (mean age 21.75 ± 2.43; 67.3% females). Results: The majority of the Lebanese university students in our sample were found to have an intermediate typology (63.0%), followed by the evening typology, which appeared to constitute 28.2% of the sample, while only 8.8% possessed a morning typology. In this study, having an intermediate or evening typology compared to a morning one was significantly associated with higher depression and worse sleep quality. In addition, having an evening chronotype compared to a morningness propensity was significantly associated with more anxiety. Conclusion: This study found a positive association between an evening typology (chronotype) and higher depression and anxiety and poorer quality of sleep. Although preliminary and based on cross-sectional data, this research could help provide a better understanding of the different chronotypes among university students, and of the possible increased susceptibility of some of these typologies (i.e., evening-type) to mental health problems.

The Association between Circadian Syndrome and Frailty in US adults: a cross-sectional study of NHANES Data from 2007 to 2018

PURPOSE

Frailty and Circadian Syndrome (CircS) are prevalent among the elderly, yet the link between them remains underexplored. This study aims to examine the association between CircS and frailty, particularly focusing on the impact of various CircS components on frailty.

MATERIALS AND METHODS

We conducted a cross-sectional analysis using data from the National Health and Nutrition Examination Survey (NHANES) spanning 2007 to 2018. The 49-item Frailty Index (FI) was employed to assess frailty. To understand the prevalence of CircS in relation to frailty, we applied three multivariate logistic regression models. Additionally, subgroup and interaction analyses were performed to investigate potential modifying factors.

RESULTS

The study included 8,569 participants. In fully adjusted models, individuals with CircS showed a significantly higher risk of frailty compared to those without CircS (Odds Ratio [OR] = 2.18, 95% Confidence Interval [CI]: 1.91-2.49, p < 0.001). A trend of increasing frailty risk with greater CircS component was observed (trend test p < 0.001). Age (p = 0.01) and race (p = 0.02) interactions notably influenced this association, although the direction of effect was consistent across subgroups. Sensitivity analysis further confirmed the strength of this relationship.

CONCLUSION

This study identifies a strong positive correlation between CircS and frailty in the elderly. The risk of frailty escalates with an increasing number of CircS components. These findings highlight the intricate interplay between circadian syndrome and frailty in older adults, offering valuable insights for developing targeted prevention and intervention strategies.

Sex modulated the relationship between trait approach motivation and decision-making

It has been observed that one's Behavioral Approach System (BAS) can have an effect on decision-making under uncertainty, although the results have been mixed. To discern the underlying neural substrates, we hypothesize that sex may explain the conflicting results. To test this idea, a large sample of participants was studied using resting state fMRI, utilizing fractional Amplitude of Low Frequency Fluctuations (fALFF) and Resting-State Functional Connectivity (rsFC) techniques. The results of the Iowa Gambling Task (IGT) revealed an interaction between sex and BAS, particularly in the last 60 trials (decision-making under risk). Males with high BAS showed poorer performance than those with low BAS. fALFF analysis showed a significant interaction between BAS group and sex in the left superior occipital gyrus, as well as the functional connectivity between this region and the left ventrolateral prefrontal cortex. Additionally, this functional connectivity was further positively correlated with male performance in the IGT, particularly in the decision-making under risk stage. Furthermore, it was found that the functional connectivity between left ventrolateral prefrontal cortex and left superior occipital gyrus could mediate the relationship between BAS and decision-making in males, particularly in the decision-making under risk stage. These results suggest possible sex-based differences in decision-making, providing an explanation for the inconsistent results found in prior research. Since the research was carried out exclusively with Chinese university students, it is essential to conduct further studies to investigate whether the findings can be generalized.

SleepInvestigatoR: A flexible R function for analyzing scored sleep in rodents

Analyzing scored sleep is a fundamental prerequisite to understanding how sleep changes between health and disease. Classically, this is accomplished by manually calculating various measures (e.g., percent of non-rapid eye movement sleep) from a collection of scored sleep files. This process can be tedious and error prone especially when studies include a large number of animals or involve long recording sessions. To address this issue, we present SleepInvestigatoR, a versatile tool that can quickly organize and analyze multiple scored sleep files into a single output. The function is written in the open-source statistical language R and has a total of 25 parameters that can be set to match a wide variety of experimenter needs. SleepInvestigatoR delivers a total of 22 unique measures of sleep, including all measures commonly reported in the rodent literature. A simple plotting function is also provided to quickly graph and visualize the scored data. All code is designed to be implemented with little formal coding knowledge and step-by-step instructions are provided on the corresponding GitHub page. Overall, SleepInvestigatoR provides the sleep researcher a critical tool to increase efficiency, interpretation, and reproducibility in analyzing scored rodent sleep.

Association between mild depressive states in polycystic ovary syndrome and an unhealthy lifestyle

Objective

Polycystic Ovary Syndrome (PCOS) is a prevalent and frequently encountered gynecological disorder. Its high variability and the complexities associated with its management often lead to psychological stress in affected women, manifesting in symptoms of depression. Embracing a healthy lifestyle is fundamental in PCOS treatment. Consistent adherence to a healthy lifestyle not only aids in improving PCOS symptoms but also plays a role in enhancing mental well-being. However, there is currently limited research examining the extent of depression, its prevalence, and its correlation with lifestyle among individuals with PCOS. Therefore, this study aims to explore the impact of lifestyle factors on the depressive state of individuals with PCOS.

Methods

This cross-sectional study gathered data from 411 individuals with PCOS at a comprehensive hospital in Henan, China. Depression status was assessed using the Hamilton Depression Scale, and demographic information as well as lifestyle habits were simultaneously collected. Univariate and multivariate analyses using logistic regression were conducted to identify risk factors associated with the depressive state in PCOS.

Results

Among the surveyed 411 individuals with PCOS, approximately 49.4% exhibited symptoms of depression, with 83.7% experiencing mild depressive symptoms. A disease duration of 1-3 years, the presence of acne, and unhealthy lifestyle factors such as high-fat diet, staying up late, lack of exercise, and mental stress emerged as significant risk factors for the onset of depressive symptoms.

Conclusion

Depressive symptoms in individuals with PCOS are predominantly mild. The risk of comorbid depression in PCOS is associated with the presence of acne, frequent high-fat diet, regular staying up late, lack of exercise, and mental stress.

Spatiotemporal light exposure modeling for environmental circadian misalignment and solar jetlag

Background

Light exposure is the most powerful resetting signal for circadian rhythms. The objective of this study was to develop and validate a high-resolution geospatial light exposure model that measures environmental circadian misalignment (or solar jetlag) as the mismatch between the social clock and sun clock, which occurs from geographic variation in light exposure leading to delayed circadian phase from relatively less morning light exposure and greater evening light exposure with increasing westward position within a time zone.

Methods

The light exposure model (30 m2 spatial resolution) incorporated geospatial data across the United States on time zones, elevation (using Google Earth Engine), sunrise time, and sunset time to estimate solar jetlag scores (higher values indicate higher environmental circadian misalignment). The validation study compared the light exposure model in 2022, which was linked with geocoded residential addresses of n = 20 participants in Boston, MA (eastern time zone position) and Seattle, WA (western time zone position) using a geographic information system, with illuminance values captured from wearable LYS light sensors and with sun times from the Solar Calculator.

Results

Western versus eastern positions within a time zone were associated with higher solar jetlag scores from the light exposure model (P < 0.01) and relatively larger differences in sunset time measured using light sensors (social clock) and the Solar Calculator (sun clock) (P = 0.04).

Conclusion

We developed and validated a geospatial light exposure model, enabling high spatiotemporal resolution and comprehensive characterization of geographic variation in light exposure potentially impacting circadian phase in epidemiologic studies.

Is the association between social jetlag and BMI mediated by lifestyle? A cross-sectional survey study in the Dutch general population

OBJECTIVE

Social jetlag is a discordance between the social and biological rhythm and is associated with higher HbA1c, higher BMI, and higher odds of obesity. The pathways that could explain these associations are still debated. This study aims to assess the mediating role of several lifestyle factors in the cross-sectional association between social jetlag and BMI.

METHODS

We used cross-sectional data from 1784 adults from urban areas in the Netherlands, collected in 2019. Social jetlag (difference in midpoint of sleep between week and weekend nights) was categorized as low(<1 h), moderate(1-2h), and high(>2 h). BMI(kg/m2) was calculated from self-reported height and weight. The association between social jetlag and BMI was assessed using linear regression, adjusted for sex, age, education, and sleep duration and stratified for the effect modifier stress (high vs. low). Mediation analysis was performed for self-reported smoking, physical activity, alcohol consumption, and adherence to a healthy diet.

RESULTS

High social jetlag was associated with higher BMI (0.69 kg/m2,95%CI 0.05;1.33). This association was stronger in people with high stress (0.93 kg/m2,95%CI 0.09;1.76). Social jetlag was also associated with higher odds of smoking, lower physical activity, higher alcohol consumption, and lower healthy diet adherence. In people with high stress, these factors mediated 10-15% of the association between social jetlag and BMI.

CONCLUSIONS

Social jetlag is associated with higher BMI and this association is stronger in people with high stress. In people with high stress, healthy diet adherence mediated 12% of this association. Other pathways involved in this association should be further investigated.

Effect of 60 days of head down tilt bed rest on amplitude and phase of rhythms in physiology and sleep in men

Twenty-four-hour rhythms in physiology and behaviour are shaped by circadian clocks, environmental rhythms, and feedback of behavioural rhythms onto physiology. In space, 24 h signals such as those associated with the light-dark cycle and changes in posture, are weaker, potentially reducing the robustness of rhythms. Head down tilt (HDT) bed rest is commonly used to simulate effects of microgravity but how HDT affects rhythms in physiology has not been extensively investigated. Here we report effects of -6° HDT during a 90-day protocol on 24 h rhythmicity in 20 men. During HDT, amplitude of light, motor activity, and wrist-temperature rhythms were reduced, evening melatonin was elevated, while cortisol was not affected during HDT, but was higher in the morning during recovery when compared to last session of HDT. During recovery from HDT, time in Slow-Wave Sleep increased. EEG activity in alpha and beta frequencies increased during NREM and REM sleep. These results highlight the profound effects of head-down-tilt-bed-rest on 24 h rhythmicity.

Frontal P300 asymmetry and congruence judgment: Retroactive switching is impaired during school day mornings in female adolescents

Investigating frontal EEG asymmetry as a possible biomarker of cognitive control abilities is especially important in ecological contexts such as school and work. We used a novel approach combining judgment performance and hemispheric frontal event-related potential (ERP) P300 asymmetry (fP3As) to evaluate aspects of cognitive control (i.e., repetition and switching) in adolescent females over a two-week ordinary school period. While undergoing electroencephalographic recording, students performed a word-colour "Stroop-like" congruence judgment task during morning and afternoon sessions, on Mondays and Wednesdays. Proportion of incongruence and congruence trials was 75% and 25%, respectively. ERP analysis revealed larger "novelty" right hemispheric fP3As amplitude for infrequent congruence but equivalent or significantly smaller than left hemispheric fP3As amplitude for frequent incongruence. RTs increased with extent of right fP3As shift. Behaviorally, repeat trial pairs (i.e., congruent followed by congruent, incongruent followed by incongruent) generally did not differ by time or day and were associated with near-ceiling accuracy. In contrast, switch trial pairs (i.e., congruent followed by incongruent, incongruent followed by congruent) in the afternoon were slower and associated with lower accuracy at the expected 75% criterion rate (i.e., judging incongruence by default), dropping significantly below 75% in the mornings. Crucially, compared to afternoon, morning fP3As patterns did not change adaptively with switch trial pairs. Although retroactive switching during congruence judgment was affected at all testing times, we conclude it was most impaired in the mornings of both early and mid school weeks, supporting misalignment between adolescent circadian cycle and school start time. We discuss some implications for optimal learning of adolescents at school.

The missing hallmark of health: psychosocial adaptation

The eight biological hallmarks of health that we initially postulated (Cell. 2021 Jan 7;184(1):33-63) include features of spatial compartmentalization (integrity of barriers, containment of local perturbations), maintenance of homeostasis over time (recycling & turnover, integration of circuitries, rhythmic oscillations) and an array of adequate responses to stress (homeostatic resilience, hormetic regulation, repair & regeneration). These hallmarks affect all eight somatic strata of the human body (molecules, organelles, cells, supracellular units, organs, organ systems, systemic circuitries and meta-organism). Here we postulate that mental and socioeconomic factors must be added to this 8×8 matrix as an additional hallmark of health ("psychosocial adaptation") and as an additional stratum ("psychosocial interactions"), hence building a 9×9 matrix. Potentially, perturbation of each of the somatic hallmarks and strata affects psychosocial factors and vice versa. Finally, we discuss the (patho)physiological bases of these interactions and their implications for mental health improvement.

Disruption of circadian rhythms promotes alcohol use: a systematic review

This systematic review investigates the bidirectional relationship between alcohol consumption and disrupted circadian rhythms. The goal of this study was to identify (i) the types of circadian rhythm disruptors (i.e. social jet lag, extreme chronotypes, and night shift work) associated with altered alcohol use and (ii) whether sex differences in the consequences of circadian disruption exist. We conducted a search of PubMed, Embase, and PsycINFO exclusively on human research. We identified 177 articles that met the inclusion criteria. Our analyses revealed that social jet lag and the extreme chronotype referred to as eveningness were consistently associated with increased alcohol consumption. Relationships between night shift work and alcohol consumption were variable; half of articles reported no effect of night shift work on alcohol consumption. Both sexes were included as participants in the majority of the chronotype and social jet lag papers, with no sex difference apparent in alcohol consumption. The night shift research, however, contained fewer studies that included both sexes. Not all forms of circadian disruption are associated with comparable patterns of alcohol use. The most at-risk individuals for increased alcohol consumption are those with social jet lag or those of an eveningness chronotype. Direct testing of the associations in this review should be conducted to evaluate the relationships among circadian disruption, alcohol intake, and sex differences to provide insight into temporal risk factors associated with development of alcohol use disorder.

Circadian rhythms and mood disorders: Time to see the light

The importance of time is ever prevalent in our world, and disruptions to the normal light/dark and sleep/wake cycle have now become the norm rather than the exception for a large part of it. All mood disorders, including seasonal affective disorder (SAD), major depressive disorder (MDD), and bipolar disorder (BD), are strongly associated with abnormal sleep and circadian rhythms in a variety of physiological processes. Environmental disruptions to normal sleep/wake patterns, light/dark changes, and seasonal changes can precipitate episodes. Moreover, treatments that target the circadian system have proven to be therapeutic in certain cases. This review will summarize much of our current knowledge of how these disorders associate with specific circadian phenotypes, as well as the neuronal mechanisms that link the circadian clock with mood regulation. We also discuss what has been learned from therapies that target circadian rhythms and how we may use current knowledge to develop more individually designed treatments.

Development and validation of a French version of the morningness-eveningness questionnaire

The aim of this study was to validate a French version (FMEQ) of the morningness-eveningness questionnaire (MEQ). Study 1 consisted of a translation by experts and an evaluation. The FMEQ and MEQ were proposed to 19 bilingual participants (age = 38.7 ± 13.7 years). Strong correlations between MEQ and FMEQ were obtained for most items. Study 2 tested the factorial structure and reliability of the FMEQ on a sample of 187 participants (20.46 ± 1.31 years). The confirmatory factor analysis indicated that the model had a good fit (χ2/df = 1.8; SRMR = 0.057) and a good reliability (Cronbach's alphas = 0.8). Concerning the temporal stability (20 participants: 20.48 ± 1.04 years), the Pearson r correlation coefficient for test-retest reliability was 0.87 (p < 0.001). Study 3 examined the predictive validity with 42 participants (19.52 ± 2.08 years). The global score of the FMEQ was significantly correlated with the time of peak temperature, wake-up time and bedtime. We did not observe superiority of a three-factors solution of the FMEQ. From now on, French subjects chronotype could be rigorously scored, and results from MEQ and FMEQ could be compared.

Different sleep patterns during the COVID-19 pandemic: association with mood, exercise and light exposure

The aim was to evaluate the sleep-wake cycle pattern, mood, perceived stress and some behaviors, such as physical exercise and exposure to natural light of college students during the COVID-19 pandemic. This is a cross-sectional study conducted between June and August 2020 using an electronic form provided by Google. The sample consisted of undergraduate students aged between 18 and 30 years old and residents of the northeast region of Brazil. The students generally had sleepiness and poor sleep quality, high levels of anxiety, mild to moderate depressive symptoms and moderate perceived stress. Some of these aspects were worse in women. The college students showed three sleep patterns: one group had good sleep quality without excessive daytime sleepiness; another group had poor sleep quality, but no excessive daytime sleepiness; and a third group had high daytime sleepiness, and less expressive sleep quality impairment. Greater exposure to sunlight and practicing physical exercise predominated in individuals with better sleep quality, suggesting that they are protective factors. In addition, excessive daytime sleepiness and poor sleep quality were separately associated with higher anxiety, depression and stress perception levels, proving to be important aspects for care in order to favor mental health during the pandemic. In conclusion, it is suggested that the COVID-19 pandemic affected the sleep of college students in a heterogeneous way. The differentiated sleep patterns are associated with exposure to natural light and exercising.

Permanent standard time is the optimal choice for health and safety: an American Academy of Sleep Medicine position statement

The period of the year from spring to fall, when clocks in most parts of the United States are set one hour ahead of standard time, is called daylight saving time, and its beginning and ending dates and times are set by federal law. The human biological clock is regulated by the timing of light and darkness, which then dictates sleep and wake rhythms. In daily life, the timing of exposure to light is generally linked to the social clock. When the solar clock is misaligned with the social clock, desynchronization occurs between the internal circadian rhythm and the social clock. The yearly change between standard time and daylight saving time introduces this misalignment, which has been associated with risks to physical and mental health and safety, as well as risks to public health. In 2020, the American Academy of Sleep Medicine (AASM) published a position statement advocating for the elimination of seasonal time changes, suggesting that evidence best supports the adoption of year-round standard time. This updated statement cites new evidence and support for permanent standard time. It is the position of the AASM that the United States should eliminate seasonal time changes in favor of permanent standard time, which aligns best with human circadian biology. Evidence supports the distinct benefits of standard time for health and safety, while also underscoring the potential harms that result from seasonal time changes to and from daylight saving time.

CITATION

Rishi MA, Cheng JY, Strang AR, et al. Permanent standard time is the optimal choice for health and safety: an American Academy of Sleep Medicine position statement. J Clin Sleep Med. 2024;20(1):121-125.

Evening Chronotype and Suicide: Exploring Neuroinflammation and Psychopathological Dimensions as Possible Bridging Factors-A Narrative Review

A chronotype is generally defined as the variability of the phase angle of entrainment, while the latter reflects the relationship between the timing of a certain rhythm (e.g., the sleep-wake cycle) and the timing of an external temporal cue. Individuals can be placed on a spectrum from "morning types" (M types) to "evening types" (E types). E-chronotype has been proposed as a transdiagnostic risk factor for psychiatric conditions, and it has been associated with psychopathological dimensions. Eveningness seems to be correlated with both suicidal ideation (SI) and suicidal behavior (SB) through several possible mediating factors. Immunological alterations have also been linked to later chronotypes and SI/SB. This narrative review aims to summarize the evidence supporting the possible association between chronotypes and suicide and the eventual mediating role of neuroinflammation and several psychopathological dimensions. A search of the literature (2003-2023) was conducted using various databases: PUBMED, EMBASE, Scopus, UpToDate, PsycINFO, and Cochrane Library. English-language articles were collected and screened for eligibility. Despite the apparent absence of a direct correlation between E-chronotype and suicidality, E-chronotype promotes a chain of effects that could be involved in an increased risk of SB, in which with neuroinflammation possibly plays an intriguing role and some psychopathological dimensions may stand out.

The Impact of Delayed School Start Times During COVID-19 on Academic Performance: A Longitudinal Naturalistic Study in Italian High Schools

Background

Delaying school start times has been proposed as a potential solution to address chronic sleep curtailment among adolescents and its negative consequences on their physical and mental well-being. This study investigates the impact of delayed school start times due to the COVID-19 pandemic on academic achievement.

Subjects and Methods

Two separate observational studies were conducted involving high school students from the first/second year (n=232) (Study 1) and from the final year (n=39) (Study 2). Multivariate Analyses of Covariance were performed to assess for statistical differences in academic performance (ie, global, humanistic, and scientific performance) and absenteeism (ie, number of school absences). Two main factors were considered: "school start time" (ie, standard-8:00 AM vs late-9:40 AM) and "time interval" (ie, first academic semester vs second academic semester), controlling for the school year (Study 1) and circadian preference (Study 2).

Results

Delaying school start times was positively associated with better academic performance in scientific subjects among first/second-year students (F1,229=6.083, p=0.026) and global academic performance among last-year students (F1,35=4.522, p=0.041). Furthermore, first/second-year students significantly increased their school achievement (F1,229>29.423, p<0.001) and school absences (F1,229=66.160, p<0.001) during the second semester of the academic year. No significant effect of "school start time" on school attendance was observed. Additionally, circadian preference was found to be a significant covariate among last-year students, with early chronotypes exhibiting better academic performance (r>0.369, p<0.025).

Conclusion

These findings confirm past evidence about the beneficial effects of delayed school start times on academic outcomes, with the additional advantage of observing them within a natural context that emerged during the pandemic. Further research is needed to explore the phenomenon more systematically and take into account the broader implications of implementing this change.

Effects of sleep-corrected social jetlag on measures of mental health, cognitive ability, and brain functional connectivity in early adolescence

Approximately half of adolescents encounter a mismatch between their sleep patterns on school days and free days, also referred to as "social jetlag." This condition has been linked to various adverse outcomes, such as poor sleep, cognitive deficits, and mental disorders. However, prior research was unsuccessful in accounting for other variables that are correlated with social jetlag, including sleep duration and quality. To address this limitation, we applied a propensity score matching method on a sample of 6335 11-12-year-olds from the 2-year follow-up (FL2) data of the Adolescent Brain Cognitive Development study. We identified 2424 pairs of participants with high sleep-corrected social jetlag (SJLsc, over 1 hour) and low SJLsc (<= 1 hour) at FL2 (1728 pairs have neuroimaging data), as well as 1626 pairs at 3-year follow-up (FL3), after matching based on 11 covariates including socioeconomic status, demographics, and sleep duration and quality. Our results showed that high SJLsc, as measured by the Munich Chronotype Questionnaire, was linked to reduced crystallized intelligence (CI), lower school performance-grades, and decreased functional connectivity between cortical networks and subcortical regions, specifically between cingulo-opercular network and right hippocampus. Further mediation and longitudinal mediation analyses revealed that this connection mediated the associations between SJLsc and CI at FL2, and between SJLsc and grades at both FL2 and FL3. We validated these findings by replicating these results using objective SJLsc measurements obtained via Fitbit watches. Overall, our study highlights the negative association between social jetlag and CI during early adolescence.