Delayed sleep-wake rhythm is associated with cognitive dysfunction, social dysfunction, and deteriorated quality of life in patients with major depressive disorder

Association between outdoor artificial light at night and executive function among depressive patients: the mediating effect of sleep timing

Recent evidence highlights the potential impact of outdoor artificial light at night (ALAN) on sleep, and later sleep timing may be a risk factor for executive dysfunction. Depression is commonly associated with executive dysfunction, which significantly compromise prognosis. However, it remains unclear whether sleep-wake phase mediate the effects of outdoor ALAN on executive function. We assessed whether sleep timing mediated the association between outdoor ALAN and executive function among depressed patients. Between 2017 and 2023, 798 inpatients with depression were enrolled from the Fourth People's Hospital of Hefei. The outdoor ALAN exposure of patients was estimated using satellite images. All participants were assessed for sleep conditions using the Pittsburgh Sleep Quality Index (PSQI) and for executive function using the Behavior Rating Inventory of Executive Function-Adult Version (BRIEF-A). We employed multifactor linear regression models to investigate the association between outdoor ALAN exposure and executive function, adjusted for potential confounders. Additionally, mediation models were utilized to explore the mediating role of sleep timing in this association. Our study found that greater ALAN exposure was significantly associated with higher executive function scores. The exposure of participants at 12 months prior to enrollment had the greatest effect, for each interquartile range (IQR 29.93 nW/cm2/sr) increase in outdoor ALAN exposure, the Global Executive Composite (GEC) scores increased by 6.12 (95 % confidence interval [CI]: 2.49, 9.74). Mediation analysis indicated that sleep midpoint significantly mediated the relationship between outdoor ALAN and executive function, with a mediated proportion of 22.39 %. The study suggested that outdoor ALAN exposure has adverse effects on executive function in depressed patients, and sleep-wake phase may mediate the association between outdoor ALAN exposure and executive function.

Sleep and circadian rhythms in delayed sleep-wake phase disorder: Phenotypic differences between patients with and without comorbid depression

Delayed sleep-wake phase disorder involves chronic difficulty going to bed and waking up at conventional times and often co-occurs with depression. This study compared sleep and circadian rhythms between patients with delayed sleep-wake phase disorder with depression (DSWPD-D) and without (DSWPD-ND) comorbid depression. Clinical records of 162 patients with delayed sleep-wake phase disorder (70 DSWPD-D, 92 DSWPD-ND) were analysed, including a subset of 76 patients with circadian phase determined by the dim light melatonin onset. Variables assessed included sleep behaviour on work and free days, weekly sleep duration, social jet lag, chronotype, and phase relationships between dim light melatonin onset and sleep/wake times. Mean (SD) or median [Q1-Q3] values were compared using t-tests or Mann-Whitney. Patients with DSWPD-D showed longer sleep on workdays (DSWPD-D = 7.63 hr [1.70] versus DSWPD-ND = 6.20 hr [1.59]; p < 0.001), but not on free days. DSWPD-D also showed later sleep onset (DSWPD-D = 03:30 14;hours [02:49 hours-04:23 hours], DSWPD-ND = 02:53 hours [02:00 hours-03:41 hours]; p = 0.02) and wake times (DSWPD-D = 11:30 hours [09:30 hours-13:00 hours], DSWPD-ND = 08:45 hours [07:20 hours-11:00 hours]; p < 0.01) on workdays. Furthermore, DSWPD-D showed less social jet lag (DSWPD-D = 0.38 [0.00-1.75] versus DSWPD-ND = 2.17 [1.25-3.03]; p < 0.01), and reported higher anxiety symptoms (DSWPD-D = 71.4% versus DSWPD-ND = 45.8%; p = 0.03) and medication use (DSWPD-D = 75.0% versus DSWPD-ND = 43.8%; p = 0.01). DSWPD-D also showed wider dim light melatonin onset phase relationships with dim light melatonin onset-mid-sleep (DSWPD-D = -5.77 [1.32] versus DSWPD-ND = -4.86 [1.53]; p = 0.01) and dim light melatonin onset-waketime (DSWPD-D = -9.46 [1.82]; DSWPD-ND = -8.13 [2.08]; p = 0.01). Multivariable Poisson regression, adjusted for age and sex, showed more medication use, less social jet lag, and longer weekly sleep duration as significantly associated with DSWPD-D. These findings suggest potential biopsychosocial protective factors linked to depression in delayed sleep-wake phase disorder. Further research is required to confirm these phenotypic differences and their relevance to delayed sleep-wake phase disorder aetiology and treatment.

Assessing Bedtime Procrastination in Iran: Psychometric Properties and Predictive Value for Insomnia

OBJECTIVES

Bedtime procrastination has been identified as an important factor associated with insufficient sleep and health and well-being problems. This study aims to investigate factor structure and psychometric properties of Bedtime procrastination Scale (BPS) in the Persian-speaking community. Additionally, this research aims to examine the role of bedtime procrastination in predicting sleep-related problems.

METHOD

Four hundred and thirty-three participants (average age 23 years, 55.7% female) took part in this study. All participants completed the BPS, the Insomnia Severity Index (ISI), and the Tuckman Procrastination Scale (TPS). Confirmatory factor analysis and hierarchical regression analysis were used to examine the factor structure and predict sleep-related problems.

RESULTS

Confirmatory factor analysis showed that, unlike other language versions, the two-factor model without item 3 was the most suitable structure. This scale demonstrated acceptable reliability and validity. Additionally, the results of hierarchical regression analysis indicated that the procrastination factor, especially bedtime procrastination, was the best predictor of insomnia severity.

CONCLUSION

In this study, the Persian version of BPS showed strong validity and reliability. These findings suggest that the Persian BPS can serve as a valuable and comprehensive research tool for assessing bedtime procrastination.

Long-lasting effects of disturbing the circadian rhythm or sleep in adolescence

Circadian rhythms are endogenous, near 24-hour rhythms that regulate a multitude of biological and behavioral processes across the diurnal cycle in most organisms. Over the lifespan, a bell curve pattern emerges in circadian phase preference (i.e. chronotype), with children and adults generally preferring to wake earlier and fall asleep earlier, and adolescents and young adults preferring to wake later and fall asleep later than their adult counterparts. This well-defined shift speaks to the variability of circadian rhythmicity over the lifespan and the changing needs and demands of the brain as an organism develops, particularly in the adolescent period. Indeed, adolescence is known to be a critical period of development during which dramatic neuroanatomical changes are occurring to allow for improved decision-making. Due to the large amount of re-structuring occurring in the adolescent brain, circadian disruptions during this period could have adverse consequences that persist across the lifespan. While the detrimental effects of circadian disruptions in adults have been characterized in depth, few studies have longitudinally assessed the potential long-term impacts of circadian disruptions during adolescence. Here, we will review the evidence that disruptions in circadian rhythmicity during adolescence have effects that persist into adulthood. As biological and social time often conflict in modern society, with school start times misaligned with adolescents' endogenous rhythms, it is critical to understand the long-term impacts of disrupted circadian rhythmicity in adolescence.

Sleep-wake behavioral characteristics associated with depression symptoms: findings from the Multi-Ethnic Study of Atherosclerosis

STUDY OBJECTIVES

To help prioritize target/groups for experimental intervention studies, we characterized cross-sectional associations between 24-hour sleep-wake measures and depression symptoms, and evaluated if similar sleep-wake-depression relationships existed in people with and without higher insomnia severity.

METHODS

Participants had ≥3 days of actigraphy data (n = 1884; mean age = 68.6/SD = 9.1; 54.1% female). We extracted 18 sleep, activity, timing, rhythmicity, and fragmentation measures from actigraphy. We used individual and multivariable regressions with the outcome of clinically significant depression symptoms (Center for Epidemiologic Studies Depression Scale ≥ 16). We conducted sensitivity analyses in people with higher insomnia severity (top quartile of the Women's Health Initiative Insomnia Rating Scale total score).

RESULTS

From separate models in the overall sample, the odds of having depression symptoms were higher with: later timing (e.g. activity onset time odds ratio [OR]/1 SD = 1.32; 95% confidence interval [CI]: 1.16 to 1.50), lower rhythmicity (e.g. pseudo-F OR/1 SD = 0.75; 95% CI: 0.66 to 0.85), less activity (e.g. amplitude OR/1 SD = 0.83; 95% CI: 0.72 to 0.95), and worse insomnia (OR/1 SD = 1.48, 95% CI: 1.31 to 1.68). In multivariable models conducted among people with lower insomnia severity, later timing, lower rhythmicity, and higher insomnia severity were independent correlates of depression. In people with higher insomnia symptom severity, measures of later timing were most strongly associated with depression symptoms.

CONCLUSIONS

These correlative observations suggest that experimental studies are warranted to test if: broadly promoting 24-hour sleep-wake functioning reduces depression even in people without severe insomnia, and if advancing timing leads to depression symptom reductions in people with insomnia.

Attenuation of homeostatic sleep response and rest-activity circadian rhythm in vitamin D deficient mice

The link between vitamin D deficiency (VDD) and sleep disturbances has long been suggested. However, the direct causality between VDD, sleep disturbances, and circadian rhythm remains unclear. We aimed to characterize sleep-wake behavior and circadian rhythms in an animal model of VDD. VDD was induced by feeding vitamin D-deficient chow, and we analyzed sleep and circadian rhythm parameters. During light period, VDD mice exhibited reduced wake with more frequent wake bouts and increased NREM sleep time. However, during dark period, the wake EEG power spectrum peaked at theta band frequency, and slow-wave energy was suppressed in mice with VDD. Rest-activity analyses revealed increased circadian period, lower wheel counts, and more frequent and short activity bouts during VDD. Combining sleep and circadian data, we found significantly suppressed activities during the hours with a wake duration shorter than 30 minutes. Moreover, mice in VDD state exhibited a negative correlation between wake theta power and hourly wheel-running counts during dark period. Our data point to a direct link between VDD and disturbances in sleep and rest-activity circadian rhythm, featuring frequent wake bouts during the sleeping phase, reduced sleep pressure build-up in dark period, and reduced activity levels due to increased susceptibility to sleepiness.

Being a morning man has causal effects on the cerebral cortex: a Mendelian randomization study

Introduction

Numerous studies have suggested a connection between circadian rhythm and neurological disorders with cognitive and consciousness impairments in humans, yet little evidence stands for a causal relationship between circadian rhythm and the brain cortex.

Methods

The top 10,000 morningness-related single-nucleotide polymorphisms of the Genome-wide association study (GWAS) summary statistics were used to filter the instrumental variables. GWAS summary statistics from the ENIGMA Consortium were used to assess the causal relationship between morningness and variates like cortical thickness (TH) or surficial area (SA) on the brain cortex. The inverse-variance weighted (IVW) and weighted median (WM) were used as the major estimates whereas MR-Egger, MR Pleiotropy RESidual Sum and Outlier, leave-one-out analysis, and funnel-plot were used for heterogeneity and pleiotropy detecting.

Results

Regionally, morningness decreased SA of the rostral middle frontal gyrus with genomic control (IVW: β = -24.916 mm, 95% CI: -47.342 mm to -2.490 mm, p = 0.029. WM: β = -33.208 mm, 95% CI: -61.933 mm to -4.483 mm, p = 0.023. MR Egger: β < 0) and without genomic control (IVW: β = -24.581 mm, 95% CI: -47.552 mm to -1.609 mm, p = 0.036. WM: β = -32.310 mm, 95% CI: -60.717 mm to -3.902 mm, p = 0.026. MR Egger: β < 0) on a nominal significance, with no heterogeneity or no outliers.

Conclusions and implications

Circadian rhythm causally affects the rostral middle frontal gyrus; this sheds new light on the potential use of MRI in disease diagnosis, revealing the significance of circadian rhythm on the progression of disease, and might also suggest a fresh therapeutic approach for disorders related to the rostral middle frontal gyrus-related.