Variability of sleep duration is related to subjective sleep quality and subjective well-being: an actigraphy study

Daily associations among sleep, posttraumatic stress disorder, and positive affect

Research suggests a bidirectional association between sleep disturbances and posttraumatic stress disorder (PTSD) symptoms. However, most studies have been conducted with group-level data, which do not necessarily capture the associations between PTSD symptoms and sleep within an individual over time. This study aimed to add to the literature concerning the association between sleep and PTSD and extend these findings to investigate the effect of sleep disturbances on positive affect. Ecological momentary assessment (EMA) was used to examine the daily temporal dynamics of sleep disturbances (i.e., self-reported difficulty initiating and maintaining sleep, disturbing dreams) and PTSD symptoms over 14 days in a sample of 41 trauma-exposed individuals. Multilevel models were employed to disambiguate within-person effects (i.e., intraindividual variability) from between-person effects (i.e., interindividual variability). Difficulty sleeping predicted increased PTSD symptoms at both the within-person, β = .11, and between-person levels, β = .38, as did disturbing dreams, within: β = .14, between: β = .31. Participants with higher PTSD symptom levels were likely to report increased difficulty sleeping at night, β = .40. Positive affect was unrelated to sleep at the within-person level but increased average sleep difficulty predicted lower positive affect at the between-person level. The findings indicate that sleep difficulties must be considerably more substantial than usual to affect PTSD symptoms in a noticeable way.

Exploratory analyses of sleep intraindividual variability and fatigue in parents of children on the autism spectrum

Fatigue is associated with numerous harmful physical and mental health outcomes. Despite the established relationship between sleep and fatigue, research examining sleep variability within a person (i.e. intraindividual variability; IIV) and fatigue is limited. In addition, the associations between child and parent sleep regarding parent fatigue have not been explicitly explored, which could be relevant for parents of autistic children with increased sleep disturbance likelihood. The current study used two weeks of objective sleep (actigraphy) and subjective fatigue data from 81 parents and their children to explore associations among child sleep IIV, parent sleep IIV, and parent average daily fatigue, including evaluating evidence for mediation. Sleep IIV was estimated using a validated Bayesian model. Linear regression analyses indicated that greater parent total sleep time IIV predicted significantly higher fatigue levels. Child sleep IIV was unrelated to parent sleep IIV and fatigue, unsupportive of hypothesized mediation. Similarly, post hoc analyses examining child sleep averages, parent total sleep time IIV, and average parent fatigue were insignificant. Findings cautiously support the uniqueness of total sleep time IIV within parental sleep's relationship with fatigue, independent of child sleep. Objective sleep IIV should continue to be examined in addition to average levels.Lay abstractFatigue is associated with numerous harmful physical and mental health outcomes. Despite research indicating a relationship between fatigue and sleep, there has been a limited focus on how the variability of a person's sleep may be associated with fatigue. In addition, previous studies have not explicitly explored relationships among child sleep, parent sleep, and parent fatigue. Increasing knowledge about this area of research could be particularly relevant for families with autistic children with an increased likelihood of sleep disturbances. The current study used two weeks of objective sleep (actigraphy) data and subjective ratings of parent fatigue from 81 parents and their autistic children to examine associations among child and parent within-person sleep variability regarding average parent fatigue levels. Evidence was assessed for the role of parent sleep variability in hypothesized connections between child sleep variability and parent fatigue. We found that only greater variability in parents' total sleep time was associated with higher levels of parents' average daily fatigue rating over the two weeks. Child sleep variability was not significantly associated with parent sleep variability or average daily fatigue. In addition, average levels of child sleep were unrelated to parent total sleep time variability and fatigue. Although cautious interpretation is required, findings support the idea that variability in total sleep time may be a unique aspect of parental sleep's association with fatigue, independent of child sleep. In addition, sleep variability could be important to consider when examining sleep in addition to average levels of parameters like total sleep time.

Associations between intraindividual variability in weekday-weekend sleep timing and duration and eating disorder pathology

Sleep disruptions may be risk factors for eating disorder symptoms. However, mean estimates of sleep characteristics may not be ideal metrics, considering many individuals have irregular sleep patterns. Although variability in sleep-wake timing is associated with irregular eating patterns among individuals with eating disorders (Linnaranta et al., 2020), studies of sleep intraindividual variability (IIV) and eating pathology are limited. To fill this gap, we evaluated two indices of sleep IIV from weekdays-to-weekends and their relation to eating disorder risk. The sample was drawn from the 2018-2019 Healthy Minds Study (N = 25,879). We conducted two binary logistic regressions predicting screening positive for an eating disorder from IIV indices, adjusting for depression and mean sleep time. Greater IIVtiming (i.e., greater shifts in the timing of the sleep midpoint between weekdays and weekends) was associated with greater odds of screening positive for an eating disorder (OR = 1.049). Greater IIVduration (i.e., greater shifts in duration of sleep between weekdays and weekends) was associated with lesser odds (OR = 0.967); however, suppressor effects of depression likely explain this finding. Greater mean duration of sleep was associated with lower odds of screening positive for an eating disorder in both models. Results are consistent with theories emphasizing the importance of sleep IIV in conceptualizing psychopathology risk; however, effect sizes were small and may have limited clinical significance. By only asking about mean sleep duration, clinicians may miss other sleep-related predictors of eating disorder psychopathology. Findings support investigating techniques to regularize sleep patterns among people with disordered eating.

The daily reciprocal associations between electroencephalography measured sleep and affect

Self-report studies show that sleep and positive and negative affect are closely and bidirectionally linked. However, studies assessing sleep objectively yield more inconsistent results. This study assessed the reciprocal, daily relationship between sleep as measured with electroencephalography (EEG) and affect (measured in the evening) in a natural setting. We assessed sleep both on the macrolevel (i.e., rapid eye movement [REM] sleep and slow-wave sleep [SWS] duration) and on the microlevel (i.e., REM sleep fragmentation). In this study, 33 participants (i.e., healthy college students, mean [standard deviation] age 21.55 [3.73] years, 67% female) were followed for 2 weeks. Each participant wore an EEG headband for 15 nights and had polysomnography during 3 of the 15 nights providing 72 analysable nights of polysomnography and 271 analysable nights with the EEG headband. Every evening participants reported their momentary negative and positive affect. We examined the relationship between pre-sleep affect and the sleep variables, as well as the reverse relationship, with sleep variables predicting evening affect the next day. We detected that higher negative affect in the evening was related to more fragmented REM sleep. However, this result was only found with polysomnography and not with the EEG headband. No significant associations were found between affect and time spent in REM sleep and SWS. Overall, no support was found for the reciprocal association between negative and positive affect and EEG measured sleep. Only limited support was found for an association in one direction (i.e., evening negative affect was associated with more REM sleep fragmentation at night).

Subjective sleep quality, but not objective sleep measures, mediates the relationship between pre-sleep worrying and affective wellbeing

Pre-sleep worrying is associated with sleep disturbance, which in turn is associated with impaired affective wellbeing. However, studies examining the fine-grained temporal order of these variables are still lacking. In particular, within-person mediation of the association between pre-sleep worrying and the following day's affective wellbeing by subjective and objective indicators of sleep has not been tested yet. This study investigates the extent to which pre-sleep worrying predicts positive/negative affect the following day, and whether subjective/objective sleep disturbances are possible mediators for this relationship. Data from two experience sampling studies were pooled for the analyses, resulting in a total sample of 220 participants aged between 18 and 30 years (M = 23.2 years, SD = 2.8). The hypotheses were tested at both the between- and within-subject level using causal mediation analysis. The within-subject analyses revealed partial mediation of the relationship between pre-sleep worrying and positive as well as negative affect the next day by subjective sleep quality. By contrast, sleep as measured by actigraphy appears not to be relevant for the link between pre-sleep worrying and affective wellbeing the following day. Baseline levels of depressive symptoms and sleep disturbances did not moderate the associations between pre-sleep worrying, sleep indices and affective states the following day. Improving perceived sleep quality by addressing pre-sleep worrying could be a potential avenue to enhance affective wellbeing and promote better mental health in young adults.

AI Foundation Models for Wearable Movement Data in Mental Health Research

Pretrained foundation models and transformer architectures have driven the success of large language models (LLMs) and other modern AI breakthroughs. However, similar advancements in health data modeling remain limited due to the need for innovative adaptations. Wearable movement data offers a valuable avenue for exploration, as it's a core feature in nearly all commercial smartwatches, well established in clinical and mental health research, and the sequential nature of the data shares similarities to language. We introduce the Pretrained Actigraphy Transformer (PAT), the first open source foundation model designed for time-series wearable movement data. Leveraging transformer-based architectures and novel techniques, such as patch embeddings, and pretraining on data from 29,307 participants in a national U.S. sample, PAT achieves state-of-the-art performance in several mental health prediction tasks. PAT is also lightweight and easily interpretable, making it a robust tool for mental health research. GitHub: https://github.com/njacobsonlab/Pretrained-Actigraphy-Transformer/.

Prospective associations between sleep, sensation-seeking, and mature screen usage in early adolescents: findings from the Adolescent Brain Cognitive Development study

STUDY OBJECTIVES

Early exposure to mature content is linked to high-risk behaviors. This study aims to prospectively investigate how sleep and sensation-seeking behaviors influence the consumption of mature video games and R-rated movies in early adolescents. A secondary analysis examines the bidirectional relationships between sleep patterns and mature screen usage.

METHODS

Data were obtained from a subsample of 3687 early adolescents (49.2% female; mean age: 11.96 years) participating in the Adolescent Brain and Cognitive Development study. At year 2 follow-up, participants wore Fitbit wearables for up to 21 nights to assess objective sleep measures and completed a scale about sensation-seeking traits. At year 3 follow-up, they answered questions about mature screen usage.

RESULTS

Of the sample, 41.8% of the sample reported playing mature-rated video games and 49% reported watching R-rated movies. Sensation-seeking traits were associated with R-rated movie watching 1 year later. Shorter sleep duration, later bedtime, more bedtime variability, and more social jetlag (discrepancy between the mid-sleep on weekdays and weekends) were associated with mature-rated video gaming and R-rated movie watching 1 year later. Sleep duration variability was associated with mature-rated video gaming. There was also an interaction effect: those with higher sensation-seeking scores and shorter sleep duration reported more frequent R-rated movie usage than those with longer sleep duration. Secondary analyses showed bidirectional associations between later bedtimes, more variability in bedtimes, and more social jetlag with mature screen usage.

CONCLUSIONS

Early adolescents with sensation-seeking traits and poorer sleep health were more likely to engage in mature screen usage.

The Relationship Between Intraindividual Sleep-Wake Variability and Mental Health in Adolescents

OBJECTIVE

We investigated the relationship between irregular sleep-wake patterns and other aspects of sleep and mental health among adolescents.

METHODS

Community-based sample of adolescents (n = 200, mean age 16.8; 61.7% female) completed baseline assessment (i.e. sleep quality, daytime sleepiness, depressive symptoms, social anhedonia, problematic alcohol use), and 7-8 consecutive days of wearing wrist actigraphy. Irregular sleep-wake patterns were assessed via two methods, both based on actigraphy, to capture day-to-day irregularity (intraindividual variability, IIV) and weekly irregularity (social jet lag, SJL). The Bayesian variability method was performed to calculate IIV in total sleep time (TST), sleep onset, and offset time. SJL was quantified as the actual difference in the sleep midpoint on school days versus non-school days.

RESULTS

Greater IIV in TST was associated with poorer sleep quality (B = 1.66, 95% CI, 0.14, 3.31, p < .05), and greater depressive symptoms (B = 0.72, 95% CI, 0.17, 1.35, p < .05), while greater IIV in sleep offset time was associated greater depressive symptoms (B = 0.63, 95% CI, 0.03, 1.28, p < .05), and greater problematic alcohol use (B = 0.70, 95% CI, 0.12, 1.35, p < .05), all after adjusting for age, sex, family SES, alcohol drinks, and SJL. No significant association was found with sleep onset time. Greater SJL was associated with poorer sleep quality (B = 0.40, 95% CI, 0.27, 0.54, p < .001) and fewer problematic alcohol uses (B = -0.05, 95% CI, -0.09, -0.00, p < .05), when adjusting for age, sex, family SES, and alcohol drinks.

CONCLUSION

Our findings add to a growing body of research on irregularity in sleep-wake patterns and clinical implications.

The behavioral and physiological correlates of affective mood switching in premenstrual dysphoric disorder

Premenstrual dysphoric disorder (PMDD), a more severe manifestation of premenstrual syndrome (PMS), is characterized by emotional, behavioral, and physical symptoms that begin in the mid-to-late luteal phase of the menstrual cycle, when estradiol and progesterone levels precipitously decline, and remit after the onset of menses. Remotely monitoring physiologic variables associated with PMDD depression symptoms, such as heart rate variability (HRV), sleep, and physical activity, holds promise for developing an affective state prediction model. Switching into and out of depressive states is associated with an increased risk of suicide, and therefore, monitoring periods of affective switching may help mitigate risk. Management of other chronic health conditions, including cardiovascular disease and diabetes, has benefited from remote digital monitoring paradigms that enable patients and physicians to monitor symptoms in real-time and make behavioral and medication adjustments. PMDD is a chronic condition that may benefit from real-time, remote monitoring. However, clinical practice has not advanced to monitoring affective states in real-time. Identifying remote monitoring paradigms that can detect within-person affective state change may help facilitate later research on timely and efficacious interventions for individuals with PMDD. This narrative review synthesizes the current literature on behavioral and physiological correlates of PMDD suitable for remote monitoring during the menstrual cycle. The reliable measurement of heart rate variability (HRV), sleep, and physical activity, with existing wearable technology, suggests the potential of a remote monitoring paradigm in PMDD and other depressive disorders.

Associations between Recession Hardships and Subjective and Objective Sleep Measures in the Midlife in the United States Study: Race and Gender Differences

Objectives

This study investigates the associations of retrospective reports of Recession hardships with 10-year changes in subjective and objective indicators of sleep, and whether these associations differ by race and gender.

Methods

501 adults (14.57% Black; 54.49% female) from the Midlife in the United States (MIDUS) study reported on the subjective Pittsburgh Sleep Quality Index (PSQI) across two waves (pre-Recession, collected 2004-2009; post-Recession, collected 2017-2022), as well as Recession hardships since 2008. A sub-sample of 201 adults (25.37% Black; 58.21% female) provided objective actigraphy-measured sleep data (total sleep time, sleep onset latency, sleep efficiency) across the two waves.

Results

Descriptive analyses revealed Black participants had higher average Recession hardships, poorer post-Recession PSQI scores, and poorer post-Recession actigraphy sleep quantity and quality compared to white participants. Females had higher average Recession hardships compared to males; and reported poorer post-Recession PSQI, but had better objective post-Recession sleep quantity and quality compared to males. Regression models showed Recession hardships (across overall events, and sub-domains of financial and housing hardships) were associated with poorer PSQI and actigraphy-measured sleep efficiency following the Recession, adjusting for sociodemographic covariates, corresponding pre-Recession sleep variables, and pre-Recession chronic conditions. There was no evidence for significant moderation by race on sleep outcomes. However, gender moderation indicated associations between housing hardships and poorer actigraphy-measured sleep efficiency were more apparent for females than for males.

Conclusions

Findings indicate that Recession hardships (particularly in financial and housing domains) may be manifested in poor sleep. Racial and gender groups may have differential exposure and sleep-related reactivity to Recession hardships.

The Association Study on Physical Activity Intensity, Sleep Quality, and Depression among College Students in the Central Plains Region

This investigation sought to understand how physical activity, sleep quality, and depression interrelate among university students in a particular region of China. It involved a diverse group of 2363 students from three institutions, using a cross-sectional approach with well-established measurement tools. These tools demonstrated strong reliability and validity, with Cronbach's alpha values indicating robust internal consistency. The data revealed that higher levels of physical activity were inversely related to depression and directly related to better sleep quality, highlighting the potential of exercise and sleep improvement to reduce depressive symptoms among this demographic.

The Relationship Between Big Five Personality Traits and Sleep Patterns: A Systematic Review

Sleep, an intrinsic aspect of human life, is experienced by individuals differently which may be influenced by personality traits and characteristics. Exploring how these traits influence behaviors and sleep routines could be used to inform more personalized and effective interventions to promote better sleep. Our objective was to summarize the existing literature on the relationship between personality traits and sleep patterns through a systematic review. An abstract and keyword search was conducted in PsycINFO, Cochrane and PubMed, collecting relevant literature, published between January 1980 and June 2024. A total of 1713 records were found, of which 18 studies were analyzed in the descriptive synthesis. Relevant studies covered populations in 11 different countries, Australia, China, Estonia, Finland, Germany, Italy, Japan, Poland, Turkey, the United Kingdom, and the United States, comprising a total of 58,812 subjects. All studies reported an association between a sleep pattern with at least one of the Big Five personality traits (agreeableness, conscientiousness, extraversion, neuroticism, openness to experience). Ten studies found associations between personality and sleep quality, all of which reported a link between neuroticism and sleep quality (effect sizes 0.183-0.40). Five studies found an association between conscientiousness and morningness (effect sizes 0.16-0.35). Other sleep patterns linked to personality traits included sleep duration, nightmare frequency and distress, sleep deficiency, sleep continuity, insomnia severity and sleep problems, sleep hygiene, sleep latency and daytime sleepiness. This novel systematic review confirms that sleep and personality traits are related, suggesting that those traits should be considered when trying to understand or change one's sleep behavior.

Sleep During the COVID-19 Pandemic: Longitudinal Observational Study Combining Multisensor Data With Questionnaires

BACKGROUND

The COVID-19 pandemic prompted various containment strategies, such as work-from-home policies and reduced social contact, which significantly altered people's sleep routines. While previous studies have highlighted the negative impacts of these restrictions on sleep, they often lack a comprehensive perspective that considers other factors, such as seasonal variations and physical activity (PA), which can also influence sleep.

OBJECTIVE

This study aims to longitudinally examine the detailed changes in sleep patterns among working adults during the COVID-19 pandemic using a combination of repeated questionnaires and high-resolution passive measurements from wearable sensors. We investigate the association between sleep and 5 sets of variables: (1) demographics; (2) sleep-related habits; (3) PA behaviors; and external factors, including (4) pandemic-specific constraints and (5) seasonal variations during the study period.

METHODS

We recruited working adults in Finland for a 1-year study (June 2021-June 2022) conducted during the late stage of the COVID-19 pandemic. We collected multisensor data from fitness trackers worn by participants, as well as work and sleep-related measures through monthly questionnaires. Additionally, we used the Stringency Index for Finland at various points in time to estimate the degree of pandemic-related lockdown restrictions during the study period. We applied linear mixed models to examine changes in sleep patterns during this late stage of the pandemic and their association with the 5 sets of variables.

RESULTS

The sleep patterns of 27,350 nights from 112 working adults were analyzed. Stricter pandemic measures were associated with an increase in total sleep time (TST) (β=.003, 95% CI 0.001-0.005; P<.001) and a delay in midsleep (MS) (β=.02, 95% CI 0.02-0.03; P<.001). Individuals who tend to snooze exhibited greater variability in both TST (β=.15, 95% CI 0.05-0.27; P=.006) and MS (β=.17, 95% CI 0.03-0.31; P=.01). Occupational differences in sleep pattern were observed, with service staff experiencing longer TST (β=.37, 95% CI 0.14-0.61; P=.004) and lower variability in TST (β=-.15, 95% CI -0.27 to -0.05; P<.001). Engaging in PA later in the day was associated with longer TST (β=.03, 95% CI 0.02-0.04; P<.001) and less variability in TST (β=-.01, 95% CI -0.02 to 0.00; P=.02). Higher intradaily variability in rest activity rhythm was associated with shorter TST (β=-.26, 95% CI -0.29 to -0.23; P<.001), earlier MS (β=-.29, 95% CI -0.33 to -0.26; P<.001), and reduced variability in TST (β=-.16, 95% CI -0.23 to -0.09; P<.001).

CONCLUSIONS

Our study provided a comprehensive view of the factors affecting sleep patterns during the late stage of the pandemic. As we navigate the future of work after the pandemic, understanding how work arrangements, lifestyle choices, and sleep quality interact will be crucial for optimizing well-being and performance in the workforce.

The new science of sleep: From cells to large-scale societies

In the past 20 years, more remarkable revelations about sleep and its varied functions have arguably been made than in the previous 200. Building on this swell of recent findings, this essay provides a broad sampling of selected research highlights across genetic, molecular, cellular, and physiological systems within the body, networks within the brain, and large-scale social dynamics. Based on this raft of exciting new discoveries, we have come to realize that sleep, in this moment of its evolution, is very much polyfunctional (rather than monofunctional), yet polyfunctional for reasons we had never previously considered. Moreover, these new polyfunctional insights powerfully reaffirm sleep as a critical biological, and thus health-sustaining, requisite. Indeed, perhaps the only thing more impressive than the unanticipated nature of these newly emerging sleep functions is their striking divergence, from operations of molecular mechanisms inside cells to entire group societal dynamics.

Just-in-Time Adaptive Intervention for Stabilizing Sleep Hours of Japanese Workers: Microrandomized Trial

BACKGROUND

Sleep disturbance is a major contributor to future health and occupational issues. Mobile health can provide interventions that address adverse health behaviors for individuals in a vulnerable health state in real-world settings (just-in-time adaptive intervention).

OBJECTIVE

This study aims to identify a subpopulation with vulnerable sleep state in daily life (study 1) and, immediately afterward, to test whether providing mobile health intervention improved habitual sleep behaviors and psychological wellness in real-world settings by conducting a microrandomized trial (study 2).

METHODS

Japanese workers (n=182) were instructed to collect data on their habitual sleep behaviors and momentary symptoms (including depressive mood, anxiety, and subjective sleep quality) using digital devices in a real-world setting. In study 1, we calculated intraindividual mean and variability of sleep hours, midpoint of sleep, and sleep efficiency to characterize their habitual sleep behaviors. In study 2, we designed and conducted a sleep just-in-time adaptive intervention, which delivered objective push-type sleep feedback messages to improve their sleep hours for a subset of participants in study 1 (n=81). The feedback messages were generated based on their sleep data measured on previous nights and were randomly sent to participants with a 50% chance for each day (microrandomization).

RESULTS

In study 1, we applied hierarchical clustering to dichotomize the population into 2 clusters (group A and group B) and found that group B was characterized by unstable habitual sleep behaviors (large intraindividual variabilities). In addition, linear mixed-effect models showed that the interindividual variability of sleep hours was significantly associated with depressive mood (β=3.83; P=.004), anxiety (β=5.70; P=.03), and subjective sleep quality (β=-3.37; P=.03). In study 2, we found that providing sleep feedback prolonged subsequent sleep hours (increasing up to 40 min; P=.01), and this effect lasted for up to 7 days. Overall, the stability of sleep hours in study 2 was significantly improved among participants in group B compared with the participants in study 1 (P=.001).

CONCLUSIONS

This is the first study to demonstrate that providing sleep feedback can benefit the modification of habitual sleep behaviors in a microrandomized trial. The findings of this study encourage the use of digitalized health intervention that uses real-time health monitoring and personalized feedback.

Revolutionizing Sleep Health: The Emergence and Impact of Personalized Sleep Medicine

Personalized sleep medicine represents a transformative shift in healthcare, emphasizing individualized approaches to optimizing sleep health, considering the bidirectional relationship between sleep and health. This field moves beyond conventional methods, tailoring care to the unique physiological and psychological needs of individuals to improve sleep quality and manage disorders. Key to this approach is the consideration of diverse factors like genetic predispositions, lifestyle habits, environmental factors, and underlying health conditions. This enables more accurate diagnoses, targeted treatments, and proactive management. Technological advancements play a pivotal role in this field: wearable devices, mobile health applications, and advanced diagnostic tools collect detailed sleep data for continuous monitoring and analysis. The integration of machine learning and artificial intelligence enhances data interpretation, offering personalized treatment plans based on individual sleep profiles. Moreover, research on circadian rhythms and sleep physiology is advancing our understanding of sleep's impact on overall health. The next generation of wearable technology will integrate more seamlessly with IoT and smart home systems, facilitating holistic sleep environment management. Telemedicine and virtual healthcare platforms will increase accessibility to specialized care, especially in remote areas. Advancements will also focus on integrating various data sources for comprehensive assessments and treatments. Genomic and molecular research could lead to breakthroughs in understanding individual sleep disorders, informing highly personalized treatment plans. Sophisticated methods for sleep stage estimation, including machine learning techniques, are improving diagnostic precision. Computational models, particularly for conditions like obstructive sleep apnea, are enabling patient-specific treatment strategies. The future of personalized sleep medicine will likely involve cross-disciplinary collaborations, integrating cognitive behavioral therapy and mental health interventions. Public awareness and education about personalized sleep approaches, alongside updated regulatory frameworks for data security and privacy, are essential. Longitudinal studies will provide insights into evolving sleep patterns, further refining treatment approaches. In conclusion, personalized sleep medicine is revolutionizing sleep disorder treatment, leveraging individual characteristics and advanced technologies for improved diagnosis, treatment, and management. This shift towards individualized care marks a significant advancement in healthcare, enhancing life quality for those with sleep disorders.

Optimism and Sleep in Aging Women: Bidirectional Relationships

OBJECTIVE

Sleep quality and duration are important for biological restoration and promotion of psychological well-being. Optimism may facilitate or result from sufficient sleep, but questions remain as to directionality. The present study tested how optimism is associated with levels of and variability in sleep quantity and quality in a longitudinal burst design.

METHODS

Midlife and older women ( N = 199) reported their sleep quantity and quality in online diaries for a 7-day period, every 3 months for 2 years. Optimism was measured at baseline and end-of-study. Multilevel models tested the effects of optimism on sleep. Linear regression models tested the effect of sleep on optimism.

RESULTS

Baseline optimism was associated with higher sleep quality ( γ = 2.13 [1.16 to 3.11], p < .0001) and lower intraindividual variability (IIV; night-to-night and wave-to-wave) in sleep quantity (night-to-night: γ = -0.07 [-0.13 to -0.005], p = .03; wave-to-wave: b = -0.07 [-0.12 to -0.02], p = .003). In turn, higher average sleep quality (but not quantity) was associated with higher optimism at end-of-study ( b = 0.02 [0.007 to 0.03], p = .002). Variability in sleep was unrelated to optimism.

CONCLUSIONS

Optimism may play an important role in maintaining sleep quality and consistency in sleep quantity, perhaps by buffering stress. Similarly, sleep quality may play an important role in maintaining optimism. The cycle whereby optimism and sleep enhance one another could improve physical health and psychological well-being among aging adults.

Cross-sectional associations of actigraphy-assessed sleep with dietary outcomes in emerging adults

BACKGROUND/OBJECTIVES

Emerging adults (~18-28 years of age) have a high prevalence of poor sleeping habits and poor diet quality; however, little is known on whether these poor sleeping habits are associated with dietary outcomes in this age group. This study assessed associations between actigraphy-based sleep with energy intake (EI), overall diet quality, and measures of meal timing in emerging adults.

SUBJECTS/METHODS

Data on 135 emerging adults (age = 19.4 ± 1.3 years; body mass index (BMI) = 26.5 ± 6.9 kg/m2; 58% female; 65% White) from the RIGHT Track Health project were used. Measures included actigraphy-assessed sleep duration, sleep efficiency, sleep timing midpoint, day-to-day sleep duration and sleep timing midpoint variability and combined sleep duration and sleep timing behaviors (early-bed/late-rise, early-bed/early-rise, late-bed/late-rise, late-bed/early-rise); EI (three 24-h dietary recalls), diet quality (Healthy Eating Index 2015 total score) and meal timing outcomes (timing of first and last meal intake, total duration, and midpoint of the eating window).

RESULTS

Shorter sleep duration, later sleep timing midpoint and greater sleep efficiency, as well as combined late-bed/late-rise and late-bed/early-rise groups, were associated with lower diet quality. Greater sleep timing midpoint variability was associated with higher EI, and the late-bed/early-rise group had significantly delayed first meal timing.

CONCLUSION

In emerging adults, shorter sleep duration and later sleep timing are associated with lower overall diet quality, and greater sleep timing variability is associated with higher EI. Future research is needed to examine the role of sleep on diet quality and eating habits to identify potential targets for nutritional interventions in this age group.

Associations of actigraphy-assessed sleep variables with adiposity and serum cardiometabolic outcomes in emerging adults

This study assessed associations of actigraphy-assessed sleep with adiposity and serum cardiometabolic outcomes in emerging adults, and whether sex and race modified these associations. Data on 147 emerging adults (age = 19.4 ± 1.3 years; body mass index = 26.4 ± 7.0 kg m-2 ; 59% female; 65% White) from RIGHT Track Health were used. Actigraphy-based sleep measures included sleep duration, sleep efficiency, sleep timing midpoint, day-to-day sleep duration and sleep timing midpoint variability. Combined sleep duration and sleep timing behaviours were also derived (early-bed/late-rise, early-bed/early-rise, late-bed/late-rise, late-bed/early-rise). Outcomes included body mass index and BodPod-assessed fat mass index, fasting serum leptin, C-reactive protein, and homeostatic model assessment-insulin resistance. Sleep duration was 5.4 h per night. We noted an inverse association between sleep duration and homeostatic model assessment-insulin resistance. The early-bed/early-rise group had greater body mass index, C-reactive protein and homeostatic model assessment-insulin resistance compared with the early-bed/late-rise group (referent). Sex modified associations of sleep efficiency with C-reactive protein; stratified results revealed positive association between sleep efficiency and C-reactive protein in males, but not females. Race modified associations of sleep duration with body mass index and leptin, and of sleep duration variability with C-reactive protein. Stratified analyses revealed inverse associations between sleep duration with body mass index and leptin in Black, multiracial/other race individuals only. Positive association between sleep duration variability and C-reactive protein was noted in White individuals only. Shorter sleep duration, particularly when combined with earlier sleep timing, is associated with greater adiposity and serum cardiometabolic outcomes. Additional studies are needed to assess individual- and contextual-level factors that may contribute to sex and race differences in sleep health and cardiometabolic risk in emerging adults.

Everyday Discrimination and Sleep Among Migrant and Non-migrant Filipinos: Longitudinal Analyses from the Health of Philippine Emigrants Study (HoPES)

This study aimed to (1) identify differences in sleep patterns between Filipino migrants and non-migrants across 2 years and (2) explore the impact of discrimination trajectories on sleep trajectories. The Health of Philippine Emigrants Study (HoPES) consisted of a migrant (n = 832) and non-migrant cohort (n = 805), with baseline data collected in the Philippines. Both cohorts were followed longitudinally, with the non-migrants followed in the Philippines and the migrant cohort followed to the United States. Sleep duration, quality, and difficulty were assessed with the National Institutes of Health Patient-Reported Outcomes Information System (PROMIS) inventory, and discrimination was measured with an adapted version of the Everyday Discrimination scale. Migrants reported a faster decline in sleep duration (- 12 min a year) but higher sleep quality than non-migrants over 2 years. Migrants who reported high initial levels of everyday discrimination also reported faster declines in sleep duration and a slower decline in sleep difficulty. Further, migrants who reported stable (versus declining) levels of discrimination over 2 years reported a faster decline in sleep quality. These results speak to the complexity of immigrant health patterns and long-term associations between discrimination and sleep processes.

The effects of flavonoid supplementation on the mental health of postpartum parents

Introduction

During the postpartum period, parents face psychological challenges and consequently, changes in mood and associated mood disorders have become increasingly prevalent in the 6-months following birth. Dietary flavonoids have been found to benefit mood and are therefore an appealing non-pharmacological option for potentially treating mood disorders in the postpartum. The aim of this study was to investigate whether a two-week dietary flavonoid intervention would improve mothers' and fathers' mental health in the immediate 6-month postpartum period.

Method

The study employed a randomised, parallel groups, controlled design to explore the effects of a flavonoid intervention vs. control group on several outcomes, including mood (PANAS), postpartum depression (EPDS), postpartum anxiety (PSAS-RSF-C) and quality of life (WHOQOL). Sixty participants (mothers n = 40, fathers n = 20) in the 6-month post-partum period were randomised to either a "flavonoid" or "control" condition. The flavonoid group were asked to add two flavonoid-rich foods (approximate flavonoid intake 218 mg/day) into their daily diet whilst controls (n = 23) were asked to continue with their usual diet for two-weeks (ClinicalTrials.gov (NCT04990622).

Results

Significant effects were found in the flavonoid group where mothers reported higher positive affect and lower postpartum depression after the two-week intervention relative to baseline. This finding is especially relevant as a clinical reduction in postpartum depression scores in the flavonoid group by an average 2.6 scoring points was observed, which equated to a reduction from "possible depression" at baseline to "little or no depression" at 2-weeks, which was not observed in the control group. Fathers' data was not analysed due to non-compliance with the intervention.

Discussion

This study provides evidence for the benefits of a dietary flavonoid intervention for mood and mental health in new mothers, supporting the utility of non-pharmacological, self-administrable changes to the diet for improving positive mood outcomes and reducing symptoms of postpartum depression in mothers during an especially challenging time. Further research for the effect of dietary interventions on paternal mental health is needed.

Clinical Trial Registration

ClinicalTrials.gov, identifier NCT04990622.

Neurobehavioral functions during recurrent periods of sleep restriction: effects of intra-individual variability in sleep duration

STUDY OBJECTIVES

To investigate whether neurobehavioral impairments are exacerbated during successive cycles of sleep restriction and recovery in young adults, and whether a variable short sleep schedule can mitigate these impairments relative to a stable one.

METHODS

Fifty-two healthy young adults (25 males, aged: 21-28) were randomly assigned to the stable short sleep group, the variable short sleep group, or the control group in this laboratory-based study. They underwent two baseline nights of 8-hour time-in-bed (TIB), followed by two cycles of "weekday" sleep opportunity manipulation and "weekend" recovery (8-hour TIB). During each manipulation period, the stable short sleep and the control groups received 6- and 8-hour TIBs each night respectively, while the variable short sleep group received 8-hour, 4-hour, 8-hour, 4-hour, and 6-hour TIBs from the first to the fifth night. Neurobehavioral functions were assessed five times each day.

RESULTS

The stable short sleep group showed faster vigilance deterioration in the second week of sleep restriction as compared to the first. This effect was not observed in the variable short sleep group. Subjective alertness and practice-based improvement in processing speed were attenuated in both short sleep groups.

CONCLUSIONS

In young adults, more variable short sleep schedules incorporating days of prophylactic or recovery sleep might mitigate compounding vigilance deficits resulting from recurrent cycles of sleep restriction. However, processing speed and subjective sleepiness were still impaired in both short sleep schedules. Getting sufficient sleep consistently is the only way to ensure optimal neurobehavioral functioning.

CLINICAL TRIAL

Performance, Mood, and Brain and Metabolic Functions During Different Sleep Schedules (STAVAR), https://www.clinicaltrials.gov/study/NCT04731662, NCT04731662.

Sleepy and grumpy go hand in hand for US Navy Sailors

Study Objectives

The study explores how sleep, sleep-related practices, and behaviors, in addition to various demographic and occupational characteristics, are related to overall mood of US Navy sailors when they are underway.

Methods

Longitudinal assessment of US Navy sailors performing their underway duties (N = 873, 79.2% males, median age 25 years). Participants completed standardized questionnaires, wore wrist-worn actigraphs, and completed daily activity logs.

Results

Sailors who reported worse profile of mood states (POMS) total mood disturbance scores had shorter sleep duration, worse sleep quality, and more episodes of split sleep. The group with worse mood also reported more symptoms of excessive daytime sleepiness as well as more symptoms of insomnia. In addition to sleep results, sailors with worse mood also tended to be younger, more likely to use nicotine and tobacco products, and less likely to have an exercise routine when compared to sailors with better POMS scores. Finally, the group with worse POMS scores included more enlisted personnel, tended to work more hours per day, and were more likely to stand watch-especially on rotating watch schedules.

Conclusions

The results found significant associations between the sleep practices and mood of sailors aboard US Navy ships. Numerous other demographic and occupational factors were also strongly associated with mood. This paper is part of the Sleep and Circadian Rhythms: Management of Fatigue in Occupational Settings Collection.

Association between transition patterns of sleep problems and suicidal ideation in Chinese female nurses: A prospective study

OBJECTIVE

Suicidal ideation and sleep problems are both common in nurses. However, few longitudinal studies are available to examine the temporal association between sleep and suicidal ideation in nurses.

METHOD

Data from the Health Longitudinal Survey of Nurses in Shandong Province was analyzed, involving 623 female nurses who had completed data of concern in 2018 (T1) and 2019 (T2). Sleep problem was assessed by the Pittsburgh Sleep Quality Index, in which the transition patterns for global and specific sleep component and the cumulative number of sleep component problems were defined. Suicidal ideation was measured by the ninth item of the Patient Health Questionnaire. Binary logistic regression was used to explore the association between sleep and suicidal ideation.

RESULTS

Chronic and deteriorated global sleep problems is associated with a greater risk of suicidal ideation. For the specific component of sleep, sleep disturbance and short sleep duration are associated with a higher risk of suicidal ideation. The higher number of cumulative sleep component problems is associated with a higher risk of suicidal ideation.

CONCLUSION

Findings indicate sleep disturbance and short sleep duration may be pathways to suicidal ideation. Initiatives that target at sleep problems may be important to reduce suicidal ideation in nurses.

The importance of sleep regularity: a consensus statement of the National Sleep Foundation sleep timing and variability panel

OBJECTIVE

To develop and present consensus findings of the National Sleep Foundation sleep timing and variability panel regarding the impact of sleep timing variability on health and performance.

METHODS

The National Sleep Foundation assembled a panel of sleep and circadian experts to evaluate the scientific evidence and conduct a formal consensus and voting procedure. A systematic literature review was conducted using the NIH National Library of Medicine PubMed database, and panelists voted on the appropriateness of 3 questions using a modified Delphi RAND/UCLA Appropriateness Method with 2 rounds of voting.

RESULTS

The literature search and panel review identified 63 full text publications to inform consensus voting. Panelists achieved consensus on each question: (1) is daily regularity in sleep timing important for (a) health or (b) performance? and (2) when sleep is of insufficient duration during the week (or work days), is catch-up sleep on weekends (or non-work days) important for health? Based on the evidence currently available, panelists agreed to an affirmative response to all 3 questions.

CONCLUSIONS

Consistency of sleep onset and offset timing is important for health, safety, and performance. Nonetheless, when insufficient sleep is obtained during the week/work days, weekend/non-work day catch-up sleep may be beneficial.

Assessing 'readiness' by tracking fluctuations in daily sleep duration and their effects on daily mood, motivation, and sleepiness

STUDY OBJECTIVES

Consumer sleep trackers issue daily guidance on 'readiness' without clear empirical basis. We investigated how self-rated mood, motivation, and sleepiness (MMS) levels are affected by daily fluctuations in sleep duration, timing, and efficiency and overall sleep regularity. We also determined how temporally specific these associations are.

METHODS

119 healthy university students (64 female, mean age = 22.54 ± 1.74 years) wore a wearable sleep tracker and undertook twice-daily smartphone-delivered ecological momentary assessment of mood, motivation, and sleepiness at post-wake and pre-bedtime timings for 2-6 weeks. Naps and their duration were reported daily. Nocturnal sleep on 2471 nights were examined using multilevel models to uncover within-subject and between-subject associations between sleep duration, timing, efficiency, and nap duration on following day MMS ratings. Time-lagged analyses examined the temporal specificity of these associations. Linear regression models investigated associations between MMS ratings and sleep variability, controlling for sleep duration.

RESULTS

Nocturnal sleep durations were short (6.03 ± 0.71 h), and bedtimes were late (1:42AM ± 1:05). Within-subjects, nocturnal sleep longer than a person's average was associated with better mood, higher motivation, and lower sleepiness after waking. Effects of such longer sleep duration lingered for mood and sleepiness till the pre-bedtime window (all Ps < .005) but did not extend to the next day. Between-subjects, higher intraindividual sleep variability, but not sleep duration, was associated with poorer mood and lower motivation after waking. Longer average sleep duration was associated with less sleepiness after waking and lower motivation pre-bedtime (all Ps < .05). Longer naps reduced post-nap sleepiness and improved mood. Controlling for nocturnal sleep duration, longer naps also associated with lower post-waking sleepiness on the following day.

CONCLUSIONS

Positive connections between nocturnal sleep and nap duration with MMS are temporally circumscribed, lending credence to the construction of sleep-based, daily 'readiness' scores. Higher sleep duration variability lowers an individual's post waking mood and motivation.

CLINICAL TRIAL ID

ClinicalTrials.gov NCT04880629.

The relationship between sleep and suicidality in schizophrenia spectrum and other psychotic disorders: A systematic review

Individuals with Schizophrenia Spectrum Disorders (SSDs) have significantly higher rates of suicidal thoughts, attempts, and death by suicide in comparison to the general population. Sleep disturbances (reduced duration, timing and quality of sleep) are risk factors for suicidality in the general population, with research indicating the relationship is both immediate and accumulative. Sleep disturbances are also considered to be implicated in the onset and exacerbation of psychotic symptoms in SSDs. Reducing the risk of suicidality in SSDs remains an important public health priority, thus exploration of contributing risk factors is warranted. Sleep monitoring may also offer an adjunct risk monitoring method to suicidality assessments in SSDs, and a potential treatment target for psychotic symptoms. This review aimed to explore proximal and longitudinal relationships between self-reported and objectively measured sleep and suicidality in SSDs and other psychotic disorders. A comprehensive search of four databases was conducted. Eleven studies met the inclusion criteria (10 cross sectional and 1 longitudinal). Narrative synthesis indicated that self-reported sleep disturbances and sleep disorders (e.g. insomnia) were associated with increased risk of suicidal ideation and attempt. However, one study employing polysomnography did not find sleep to be associated with suicidality. Methodological limitations of the evidence base include: i) little experimental or longitudinal evidence, (ii) self-report and/or single item assessment of sleep disturbance, (iii) limited use of validated measures of suicidality, (iv) considerable research in long-term schizophrenia but sparse evidence in early psychosis. Future research should explore (i) cross-sectional and longitudinal relationships between specific aspects of suicidality and objective sleep parameters, (ii) use qualitative or mixed-methods designs to disentangle the nuances and bidirectionality in the sleep-suicide relationship, (iii) explore the psychological processes underpinning or mediating the sleep-suicide relationship in SSDs.

Relationship of Sleep Health and Endoscopic Disease Activity in Inflammatory Bowel Disease: Endoscopic Disease Activity and Sleep

Among adults with inflammatory bowel disease (IBD), self-reported sleep disturbances are associated with active symptoms, but the association between sleep measures and endoscopic disease activity is unknown. This study aimed to (1) compare sleep-wake behaviors among IBD patients based on endoscopic and clinical disease activity and (2) describe associations between actigraphy, self-reported sleep measures, and symptoms of fatigue, anxiety, and depression. Participants wore a wrist actigraph for 10 consecutive days and completed self-reported sleep questionnaires (Pittsburgh Sleep Quality Index [PSQI] and Patient-Reported Outcome Measures System [PROMIS] Sleep Disturbance and Sleep Interference questionnaires). Clinical and endoscopic disease activity were assessed. Based on actigraphic recordings ( n = 26), average total nighttime sleep was 437 minutes and sleep efficiency was 84%. Objective sleep measures did not differ based on endoscopic or clinical disease activity. Individuals with active clinical disease had higher PROMIS Sleep Disturbance (57.3 vs. 49.7, d = 1.28) and PROMIS Sleep-Related Impairment (58.1 vs. 52.8, d = 0.51) compared with those with inactive clinical disease. Self-reported sleep was significantly associated with anxiety, depression, and fatigue. Further research is needed to better characterize the relationship between sleep and endoscopic disease activity, and determine underlying mechanisms related to poor sleep in the IBD population.

Sleep, Affect, and Emotion Reactivity in First-Year College Students: A Daily Diary Study

BACKGROUND

Sleep is an important factor in well-being, especially during the transition to college when academic and social commitments increase. Identifying factors that contribute to poor sleep (including short duration and increased variability in duration) can support development of interventions. Affect and emotion reactivity are factors that could contribute to sleep, and have not been studied in relation to sleep variables among first-year college students during their adjustment to the college environment. This adjustment might be difficult for some students, and therefore elicit affect fluctuations that contribute to poor sleep. Alternatively, sleep could contribute to daily affect. The present daily diary study examined bidirectional relations between daily sleep and affect, as well as between emotion reactivity and sleep (duration and variability) and affect (daily and overall variability) in first-year college students.

METHOD

First-year college students (n = 244; 86.1% female) completed a baseline survey including measures of emotion reactivity and anxiety and depressive symptoms, followed by 7 days of a once-per-day diary, reporting on their affect and sleep duration.

RESULTS

On days when individuals reported increased sleep duration, they also tended to experience greater positive affect the following day (p = .01). Those who experienced high levels of emotion reactivity also experienced more negative affect (p < .001) and negative affect variability (p < .001).

CONCLUSION

Emotion reactivity might identify college students who experience more negative affect and are possibly at risk to develop mental health disorders. The importance of sleep health should continue to be emphasized to students as they transition to college.

From childhood adversity to latent stress vulnerability in adulthood: the mediating roles of sleep disturbances and HPA axis dysfunction

Childhood adversity is a prominent predisposing risk factor for latent stress vulnerability, expressed as an elevated likelihood of developing stress-related psychopathology upon subsequent exposure to trauma in adulthood. Sleep disturbances have emerged as one of the most pronounced maladaptive behavioral outcomes of childhood adversity and are also a highly prevalent core feature of stress-related psychopathology, including post-traumatic stress disorder (PTSD). After reviewing the extensive literature supporting these claims, the current review addresses the notion that childhood adversity-induced sleep disturbances may play a causal role in elevating individuals' stress vulnerability in adulthood. Corroborating this, sleep disturbances that predate adult trauma exposure have been associated with an increased likelihood of developing stress-related psychopathology post-exposure. Furthermore, novel empirical evidence suggests that sleep disturbances, including irregularity of the sleep-wake cycle, mediate the link between childhood adversity and stress vulnerability in adulthood. We also discuss cognitive and behavioral mechanisms through which such a cascade may evolve, highlighting the putative role of impaired memory consolidation and fear extinction. Next, we present evidence to support the contribution of the hypothalamic-pituitary-adrenal (HPA) axis to these associations, stemming from its critical role in stress and sleep regulatory pathways. Childhood adversity may yield bi-directional effects within the HPA stress and sleep axes in which sleep disturbances and HPA axis dysfunction reinforce each other, leading to elevated stress vulnerability. To conclude, we postulate a conceptual path model from childhood adversity to latent stress vulnerability in adulthood and discuss the potential clinical implications of these notions, while highlighting directions for future research.

The impact of mindfulness training on posttraumatic stress disorder symptoms, subjective sleep quality, and objective sleep outcomes in police officers

OBJECTIVE

Sleep disturbances cooccur with posttraumatic stress disorder (PTSD) and are often correlated with PTSD severity. Previous research has shown that sleep problems mediate the relationship between PTSD and negative physical and mental health outcomes but has relied on self-reported sleep quality. We tested the effects of mindfulness training-previously shown to improve sleep quality and reduce PTSD symptoms-on subjective and objective sleep metrics and relationships with reduced PTSD symptoms.

METHOD

Following baseline data collection in 114 law enforcement officers, we randomly assigned participants to either an 8-week mindfulness training group or a waitlist control group. We repeated assessments immediately posttraining and at 3-month follow-up. Self-reported PTSD symptoms and subjective sleep quality were measured at each visit with the PTSD checklist and Pittsburgh Sleep Quality Index (PSQI), respectively. Participants also wore a Fitbit Charge 2 continuously over the course of a 4- to 6-day work week following each visit, from which we extracted two distinct objective sleep metrics: total minutes of sleep and sleep efficiency.

RESULTS

At baseline, PTSD symptoms were correlated with PSQI scores but not objective Fitbit metrics. Relative to waitlist, mindfulness training led to improved subjective sleep quality and reduced PTSD symptoms. Reduced PTSD symptoms mediated the improvement in subjective sleep quality following mindfulness training. Neither objective sleep metric demonstrated improvements following mindfulness training, nor did these metrics mediate reduced PTSD symptoms.

CONCLUSIONS

This study provides evidence linking improved subjective sleep quality, but not objective sleep markers, to reductions in PTSD symptoms following mindfulness training. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Individual light history matters to deal with the Antarctic summer

The effect of light, main zeitgeber of the circadian system, depends on the time of day it is received. A brief trip to the Antarctic summer (ANT) allowed us to explore the impact of a sudden and synchronized increase in light exposure on activity-rest rhythms and sleep patterns of 11 Uruguayan university students, and to assess the significance of light history in determining individual circadian phase shift. Measurements collected in the peri-equinox in Montevideo, Uruguay (baseline situation, MVD) and in ANT, included sleep logs, actigraphy, and salivary melatonin to determine dim-light melatonin onset (DLMO), the most reliable marker of circadian phase. The increase in light exposure in ANT with respect to MVD (affecting both light-sensitive windows with opposite effects on the circadian phase) resulted in no net change in DLMO among participants as some participants advanced their DLMO and some others delayed it. The ultimate cause of each participant's distinctive circadian phase shift relied on the unique change in light exposure each individual was subjected to between their MVD and ANT. This study shows an association between the individual light history and the circadian phase shift.

Associations between parental relationship dissolution and child sleep: A systematic review

Parental relationship dissolution is considered one of the most common adverse childhood experiences. Although sleep is crucial for healthy development of children and very sensitive to environmental changes, it is poorly studied in the context of parental relationship dissolution. The aim of the current study was to systematically review and critically assess the existing literature on the associations between parental relationship dissolution and child sleep (0-18 years old; registered on PROSPERO (CRD42021272720)). PsycInfo, MEDLINE, Scopus, ProQuest Dissertations and Theses Global, Social Work abstracts, and Web of Science Core Collection were searched. Published empirical quantitative studies were included if they reported statistics regarding the association between parental relationship dissolution and any child sleep variable. Out of the 358 articles screened, 14 articles met inclusion criteria and reported on several sleep dimensions: sleep quality, dreams and nightmares, and sleep disorders (enuresis, night terrors, and bruxism). Out of the 14 articles, six were longitudinal studies and eight were cross-sectional studies. While most studies found that parental relationship dissolution was associated with some indices of poorer child sleep, studies were generally of low to moderate quality. Health professionals should assess child sleep in the context of a parental relationship dissolution.

Health Effects of Sleep Quality in Premutation Carrier Mothers of Individuals With Fragile X Syndrome

Sleep plays an integral role in supporting well-being, and sleep difficulties are common in mothers of individuals with developmental disabilities, including fragile X syndrome (FXS). This study assessed whether the effects of sleep quality on physical health and depression are exacerbated by genetic risk factors (CGG repeats) in FMR1 premutation carrier mothers of individuals with FXS. Poor sleep quality predicted a greater number of physical health conditions for mothers with CGG repeats in the mid-premutation range (90-110 repeats), but not for those in the lower (< 90 repeats) or higher (> 110 repeats) ends of the range. A significant association between poor sleep quality and maternal depressive symptoms was also observed, but there was no evidence that this effect varied by level of genetic vulnerability. This research extends our understanding of individual differences in the effects of sleep quality among mothers of individuals with FXS.

Associations of sleep duration and sleep quality with indicators of mental health among youth and adults: findings from the 2015 Canadian Community Health Survey

INTRODUCTION

A growing number of Canadian studies have examined the link between sleep and mental health. This research builds upon that work by investigating associations of sleep duration and quality with positive mental health (PMH) and mental illness and suicidal ideation (MI/SI) outcomes among youth and adults from threeCanadian provinces (i.e. Ontario, Manitoba and Saskatchewan).

METHODS

Using cross-sectional data from respondents 12 years and older (n = 18 683) who were asked questions on their sleep in the 2015 Canadian Community Health Survey - Annual Component, we conducted unadjusted and adjusted logistic regressionswith self-reported measures of sleep duration and sleep quality as independent variables and a range of PMH (e.g. high self-rated mental health) and MI/SI indicators (e.g. mood disorder diagnosis) as dependent variables. Analyses were conducted of allcomplete cases and also stratified by sex and age group.

RESULTS

Good sleep quality was associated with higher odds of PMH indicators (adjusted odds ratio [aOR]: 1.52-4.24) and lower odds of MI/SI indicators (aOR: 0.23- 0.47); associations remained significant when analyses were stratified. Meeting sleep duration recommendations was positively associated with PMH indicators (aOR: 1.27- 1.56) and negatively associated with MI/SI indicators (aOR: 0.41-0.80), but some associations did not remain significant when stratified.

CONCLUSION

This study provides support for associations between sleep duration and quality and indicators of PMH and MI/SI. Findings can inform future research and surveillance efforts that monitor sleep behaviours and indicators of PMH and MI/SI.

Stronger Associations Between Sleep and Mental Health in Adults with Autism: A UK Biobank Study

This study examined sleep and its cognitive and affective correlates in adults with and without autism spectrum disorder (ASD), utilizing UK Biobank data. There were no group differences in subjective sleep duration [n = 220 ASD; n = 2200 general population (GP)]. Accelerometer measures of sleep duration or nighttime activity did not differ by group, but sleep efficiency was marginally lower in ASD (n = 83 ASD; n = 824 GP). Sleep efficiency was associated with wellbeing and mental health, and pathways between accelerometer sleep measures and wellbeing and mental health were significantly stronger for adults with ASD (who also reported substantially poorer wellbeing and > 5 × likelihood of experiencing mental distress). These findings highlight the need to monitor sleep to maintain good mental health in adult ASD.

Sleep Disorders during Adolescence

Sleep disorders during adolescence period increase each year and adversely affect the physical and mental health of adolescents. After-school social activities and various work outside the school may cause delays in bedtime. In addition, there can be shifts in the circadian rhythm due to a number of biological changes seen in the transition to adolescence, which can result in a wide range of sleep problems, such as not being able to fall asleep at night, difficulty waking up in the morning, daytime sleepiness, sleep deprivation and deterioration in sleep quality. It is important to know the causes of sleep disorders, possible effects on physical health and mental health, and protective and risk-forming factors seen in adolescent period; to intervene in these disorders and to develop preventive measures. Preventive measures, such as increasing awareness about sleep disorders in adolescents, informing families and adolescents about the issue, and organizing school start-up times for this age group, may contribute significantly to solving this important issue, which has increased year-to-year.

The association between sleep quality and telomere length: A systematic literature review

Several sleep parameters present an elevated risk for processes that contribute to cellular aging. Short sleep duration, sleep apnoea, and insomnia are significantly associated with shorter telomeres, a biological marker of cellular aging. However, there has been no review or analysis of studies that have examined the association between the psychological construct of sleep quality and telomere length. The present study aimed to provide a systematic review of the association between sleep quality and telomere length. A systematic review of English articles was conducted using MEDLINE/PubMed, PsycINFO, Google Scholar, and Web of Science electronic databases, with the final search conducted on 3rd September 2021. Search terms included sleep quality, poor sleep, insomnia, sleep difficulties, sleep issue*, non-restorative sleep, telomere*, cellular aging, and immune cell telomere length. Study eligibility criteria included human participants aged 18 years or older and a reproducible methodology. Study appraisal and synthesis were completed using a systematic search in line with a PICOS approach (P = Patient, problem, or population; I = Intervention, prognostic factor, exposure; C = Comparison, control, or comparator; O = Outcomes; S = Study designs). Twenty-two studies met review inclusion criteria. Qualitative synthesis of the literature indicated insufficient evidence overall to support a significant association between sleep quality and telomere length. Limitations across studies were addressed, such as the assessment of examined constructs. Findings highlight important targets for future research, including the standardised operationalisation of the sleep quality construct and experimental study designs. Research in this area has clinical significance by identifying possible mechanisms that increase the risk for age-related disease and mortality. PROSPERO Registration No.: CRD 42021233139.

Mediation analysis of circadian preferences and other behavioral and sociodemographic factors associated with subjective well-being in undergraduate students

Undergraduate students are usually subjected to a routine with constant pressure, stress, circadian misalignment, and sleep irregularity that impairs their subjective well-being. Recent evidence suggests that circadian preference is also a risk factor for impaired mental health and factors related to subjective well-being. This study aimed to identify the sociodemographic factors associated with subjective well-being and describe the mediating behavioral variables. Between September 2018 and March 2021, 615 Brazilian students enrolled in higher educational institutions completed an electronic form containing questionnaires on subjective well-being, sociodemographic, and behavioral-related factors (convenience sample). A statistical mediation model was applied to describe how these variables influence subjective well-being. We observed that Morningness (p < .001), identification with the male gender (p = .010), not working while studying (p = .048), and the practice of Pilates/yoga (p = .028) were associated with greater subjective well-being. Except for employment status, no direct effects were observed, which reinforces the need to consider a multidimensional approach. The relationship between subjective well-being and sociodemographic factors exists only in the presence of behavioral mediators, specifically perceived stress, daytime sleepiness, symptoms of depression, sleep quality, and positive and negative affects. Future work should investigate in more detail the impact of sleep, stress, and circadian preferences on this relationship.

Variability in objective sleep is associated with Alzheimer's pathology and cognition

Both sleep duration and sleep efficiency have been associated with risk of Alzheimer's disease, suggesting that interventions to promote optimal sleep may be a way to reduce Alzheimer's disease risk. However, studies often focus on average sleep measures, usually from self-report questionnaires, ignoring the role of intra-individual variability in sleep across nights quantified from objective sleep measures. The current cross-sectional study sought to investigate the role of intra-individual variability in accelerometer-based objective sleep duration and sleep efficiency in relation to in vivo Alzheimer's disease pathology (β-amyloid and tau) using positron emission tomography imaging and cognition (working memory, inhibitory control, verbal memory, visual memory and global cognition). To examine these relationships, we evaluated 52 older adults (age = 66.4 ± 6.89, 67% female, 27% apolipoprotein E4 carriers) with objective early mild cognitive impairment. Modifying effects of apolipoprotein E4 status were also explored. Less intra-individual variability in sleep duration was associated with lower β-amyloid burden, higher global cognition and better inhibitory control, with a trend for lower tau burden. Less intra-individual variability in sleep efficiency was associated with lower β-amyloid burden, higher global cognition and better inhibitory control, but not with tau burden. Longer sleep duration was associated with better visual memory and inhibitory control. Apolipoprotein E4 status significantly modified the association between intra-individual variability in sleep efficiency and β-amyloid burden, such that less sleep efficiency variability was associated with lower β-amyloid burden in apolipoprotein E4 carriers only. There was a significant interaction between sleep duration and apolipoprotein E4 status, suggesting that longer sleep duration is more strongly associated with lower β-amyloid burden in apolipoprotein E4 carriers relative to non-carriers. These results provide evidence that lower intra-individual variability in both sleep duration and sleep efficiency and longer mean sleep duration are associated with lower levels of β-amyloid pathology and better cognition. The relationships between sleep duration and intra-individual variability in sleep efficiency with β-amyloid burden differ by apolipoprotein E4 status, indicating that longer sleep duration and more consistent sleep efficiency may be protective against β-amyloid burden in apolipoprotein E4 carriers. Longitudinal and causal studies are needed to better understand these relationships. Future work should investigate factors contributing to intra-individual variability in sleep duration and sleep efficiency in order to inform intervention studies.

Sleep variability over a 2-week period is associated with restfulness and intrinsic limbic network connectivity in adolescents

STUDY OBJECTIVES

Sleep duration and intraindividual variability in sleep duration undergo substantial changes in adolescence and impact brain and behavioral functioning. Although experimental work has linked acute sleep deprivation to heightened limbic responding and reduced regulatory control, there is limited understanding of how variability in sleep patterns might interact with sleep duration to influence adolescent functioning. This is important for optimal balancing of length and consistency of sleep. Here, we investigated how objective indices of sleep duration and variability relate to stress, restfulness, and intrinsic limbic network functioning in adolescents.

METHODS

A sample of 101 adolescents ages 14-18 reported their stressors, after which they wore wrist actigraph watches to monitor their sleep and rated their restfulness every morning over a 2-week period. They also completed a resting-state fMRI scan.

RESULTS

Adolescents reporting more stress experienced shorter sleep duration and greater sleep variability over the 2-week period. Longer nightly sleep duration was linked to feeling more rested the next morning, but this effect was reduced in adolescents with high cumulative sleep variability. Sleep variability showed both linear and quadratic effects on limbic connectivity: adolescents with high sleep variability exhibited more connectivity within the limbic network and less connectivity between the limbic and frontoparietal networks than their peers, effects which became stronger once variability exceeded an hour.

CONCLUSIONS

Results suggest that cumulative sleep variability is related to stress and limbic network connectivity and shows interactive effects with sleep duration, highlighting the importance of balancing length and consistency of sleep for optimal functioning in adolescence.

Actigraphy in studies on insomnia: Worth the effort?

In the past decades, actigraphy has emerged as a promising, cost-effective, and easy-to-use tool for ambulatory sleep recording. Polysomnography (PSG) validation studies showed that actigraphic sleep estimates fare relatively well in healthy sleepers. Additionally, round-the-clock actigraphy recording has been used to study circadian rhythms in various populations. To this date, however, there is little evidence that the diagnosis, monitoring, or treatment of insomnia can significantly benefit from actigraphy recordings. Using a case-control design, we therefore critically examined whether mean or within-subject variability of actigraphy sleep estimates or circadian patterns add to the understanding of sleep complaints in insomnia. We acquired actigraphy recordings and sleep diaries of 37 controls and 167 patients with varying degrees of insomnia severity for up to 9 consecutive days in their home environment. Additionally, the participants spent one night in the laboratory, where actigraphy was recorded alongside PSG to check whether sleep, in principle, is well estimated. Despite moderate to strong agreement between actigraphy and PSG sleep scoring in the laboratory, ambulatory actigraphic estimates of average sleep and circadian rhythm variables failed to successfully differentiate patients with insomnia from controls in the home environment. Only total sleep time differed between the groups. Additionally, within-subject variability of sleep efficiency and wake after sleep onset was higher in patients. Insomnia research may therefore benefit from shifting attention from average sleep variables to day-to-day variability or from the development of non-motor home-assessed indicators of sleep quality.

Sleep Disturbances in Adolescents with Attention-Deficit/Hyperactivity Disorder

Introduction

Delayed sleep phase syndrome (DSPS) and insomnia disorders are prevalent in adolescents and are comorbid with attention-deficit/hyperactivity disorder (ADHD), but only limited information is available regarding the prevalence of DSPS and insomnia in adolescents with ADHD. Moreover, previous studies comparing objective sleep parameters averaged the findings across all participants of each group (ADHD, control) regardless of each individual's level of reported sleep disturbance. This might have resulted in inconsistency between information obtained by objective and subjective sleep measures in adolescents with ADHD. The objectives of the present study were 1) to compare the prevalence of risk for DSPS and insomnia in adolescents with ADHD and control adolescents in our samples; 2) to compare objectively measured sleep characteristics of adolescents with ADHD and controls while taking into consideration their levels of risk for DSPS or their level of insomnia; and 3) to compare the ADHD symptom levels of adolescents with moderate/high and low risk for DSPS or insomnia.

Methods

Seventy-three adolescents (37 ADHD, 36 controls) aged 12-15 years participated in a cross-sectional study. Actigraphy was used to characterize objective sleep parameters and parents' or adolescents' reports were used to characterize subjective sleep parameters.

Results

Of the participants in the ADHD and control groups, 33.33% and 27%, respectively, had moderate/high levels of risk for DSPS. Adolescents in the high-risk group for DSPS had an objectively measured delayed sleep schedule and more variable sleep duration, time in bed, and sleep efficiency compared to adolescents in the low-risk group for DSPS, regardless of their ADHD diagnosis. Adolescents with higher levels of insomnia spent more time in bed and had more variable sleep efficiency compared to adolescents with no insomnia, regardless of their diagnosis.

Conclusion

The prevalence of moderate/high risk for DSPS was similarly high in adolescents with ADHD and controls. Participants' subjective reports of sleep disturbances were consistent with their objective sleep parameters when the type and level of subjectively defined sleep disturbance were considered. ADHD symptom levels were not different in adolescents with moderate/high or low risk for DSPS or insomnia.

The variability and volatility of sleep: An ARCHetypal behavior

Using 1975-2005 Dutch time-diary data covering over 10,000 respondents for 7 consecutive days each, we show that sleep time exhibits non-constant variability, or volatility, characterized by stationary autoregressive conditional heteroscedasticity: The absolute values of deviations from a person's average sleep on one day are positively correlated with those on adjacent days. Sleep is more variable on weekends and among younger people, those without young children, or with less education. Volatility is greater among parents with young children, slightly greater among men, but independent of other demographics. Economic incentives to minimize the dispersion of sleep imply higher-wage workers will exhibit less dispersion, which we observe. Sleep volatility spills over onto volatility in other personal activities, with no reverse causation onto sleep. The results illustrate a novel dimension of inequality among people and could be applied to a wide variety of human behavior and biological processes.

Sleep Regularity and Predictors of Sleep Efficiency and Sleep Duration in Elite Team Sport Athletes

Background

Many elite athletes have suboptimal sleep duration and efficiency, potentially due to factors that may impact sleep onset and offset times. Variability in sleep onset and offset may negatively influence sleep. The sleep regularity index (SRI) is a novel metric for sleep regularity, however there are no published descriptions of SRI in elite athletes. Further, contributors to sleep efficiency and duration in elite athletes using objective measures have not been explored.

Methods

Sleep was monitored over a minimum of seven consecutive days (7 to 43)—in 203 elite team sport athletes (age range = 19–36 years; female, n = 79; male, n = 124, total sleep nights = 1975) using activity monitoring and sleep diaries. The sleep regularity index (SRI) was calculated to reflect the night-to-night shifts in sleep by accounting for changes in sleep onset and sleep offset. Sleep characteristics were compared between regular and irregular sleepers and important contributors to sleep efficiency and total sleep time were assessed using multiple linear regression models.

Results

The median sleep regularity index and interquartile range were 85.1 (81.4 to 88.8). When compared to irregular sleepers, regular sleepers demonstrated (1) significantly greater sleep efficiency (p = 0.006; 0.31 medium effect size [ES]), (2) significantly less variability in total sleep time (− p ≤ 0.001; − 0.69, large ES) and sleep efficiency (− 0.34, small ES), (3) similar total sleep time and (4) significantly less variation in sleep onset (p ≤ 0.001; − 0.73, large ES) and offset (p ≤ 0.001; − 0.74, large ES) times. Sleep characteristics explained 73% and 22% of the variance in total sleep time and sleep efficiency, respectively. The most important contributor to total sleep time was a later sleep offset time, while the most important contributors to sleep efficiency were an earlier bedtime and less variable sleep onset times.

Conclusions

Bedtime and a consistent sleep onset time are important factors associated with sleep efficiency in athletes, while sleep offset is an important factor for total sleep time. Coaches and staff can assist their athletes by providing training schedules that allow for both regularity and sufficiency of time in bed where possible.

Sleep Problems and Psychological Well-Being: Baseline Findings from the Canadian Longitudinal Study on Aging

International studies have demonstrated associations between sleep problems and poor psychological well-being; however, Canadian data are limited. This study investigated this association using cross-sectional baseline data from the Canadian Longitudinal Study on Aging, a national survey of 30,097 community-dwelling adults, 45–85 years of age. Short sleep duration, sleep dissatisfaction, insomnia symptoms, and daytime impairment were consistently associated with a higher prevalence of dissatisfaction with life, psychological distress, and poor self-reported mental health. Long sleep duration was associated with a higher prevalence of psychological distress and poor self-reported mental health, but not with dissatisfaction with life. Associations between sleep problems and psychological distress were 11–18 per cent stronger in males. With each 10-year increase in age, the association between daytime impairment and life dissatisfaction increased by 11 per cent, and insomnia symptoms and poor mental health decreased by 11 per cent. Sleep problems in middle-aged and older adults warrant increased attention as a public health problem in Canada.

Adolescent sleep and the foundations of prefrontal cortical development and dysfunction

Modern life poses many threats to good-quality sleep, challenging brain health across the lifespan. Curtailed or fragmented sleep may be particularly damaging during adolescence, when sleep disruption by delayed chronotypes and societal pressures coincides with our brains preparing for adult life via intense refinement of neural connectivity. These vulnerabilities converge on the prefrontal cortex, one of the last brain regions to mature and a central hub of the limbic-cortical circuits underpinning decision-making, reward processing, social interactions and emotion. Even subtle disruption of prefrontal cortical development during adolescence may therefore have enduring impact. In this review, we integrate synaptic and circuit mechanisms, glial biology, sleep neurophysiology and epidemiology, to frame a hypothesis highlighting the implications of adolescent sleep disruption for the neural circuitry of the prefrontal cortex. Convergent evidence underscores the importance of acknowledging, quantifying and optimizing adolescent sleep's contributions to normative brain development and to lifelong mental health.

The Effects of Objective Push-Type Sleep Feedback on Habitual Sleep Behavior and Momentary Symptoms in Daily Life: mHealth Intervention Trial Using a Health Care Internet of Things System

BACKGROUND

Sleep is beneficial for physical and mental health. Several mobile and wearable sleep-tracking devices have been developed, and personalized sleep feedback is the most common functionality among these devices. To date, no study has implemented an objective push-type feedback message and investigated the characteristics of habitual sleep behavior and diurnal symptoms when receiving sleep feedback.

OBJECTIVE

We conducted a mobile health intervention trial to examine whether sending objective push-type sleep feedback changes the self-reported mood, physical symptoms, and sleep behavior of Japanese office workers.

METHODS

In total, 31 office workers (mean age 42.3, SD 7.9 years; male-to-female ratio 21:10) participated in a 2-arm intervention trial from November 30 to December 19, 2020. The participants were instructed to indicate their momentary mood and physical symptoms (depressive mood, anxiety, stress, sleepiness, fatigue, and neck and shoulder stiffness) 5 times a day using a smartphone app. In addition, daily work performance was rated once a day after work. They were randomly assigned to either a feedback or control group, wherein they did or did not receive messages about their sleep status on the app every morning, respectively. All participants wore activity monitors on their nondominant wrists, through which objective sleep data were registered on the web on a server. On the basis of the estimated sleep data on the server, personalized sleep feedback messages were generated and sent to the participants in the feedback group using the app. These processes were fully automated.

RESULTS

Using hierarchical statistical models, we examined the differences in the statistical properties of sleep variables (sleep duration and midpoint of sleep) and daily work performance over the trial period. Group differences in the diurnal slopes for mood and physical symptoms were examined using a linear mixed effect model. We found a significant group difference among within-individual residuals at the midpoint of sleep (expected a posteriori for the difference: -15, 95% credible interval -26 to -4 min), suggesting more stable sleep timing in the feedback group. However, there were no significant group differences in daily work performance. We also found significant group differences in the diurnal slopes for sleepiness (P<.001), fatigue (P=.002), and neck and shoulder stiffness (P<.001), which was largely due to better scores in the feedback group at wake-up time relative to those in the control group.

CONCLUSIONS

This is the first mobile health study to demonstrate that objective push-type sleep feedback improves sleep timing of and physical symptoms in healthy office workers. Future research should incorporate specific behavioral instructions intended to improve sleep habits and examine the effectiveness of these instructions.

Sleep and affect: A conceptual review

Everyday experience suggests that sleep and affect are closely linked, with daytime affect influencing how we sleep, and sleep influencing subsequent affect. Yet empirical evidence for this bidirectional relationship between sleep and affect in non-clinical adult samples remains mixed, which may be due to heterogeneity in both construct definitions and measurement. This conceptual review proposes a granular framework that deconstructs sleep and affect findings according to three subordinate dimensions, namely domains (which are distinct for sleep and affect), methods (i.e., self-report vs. behavioral/physiological measures), and timescale (i.e., shorter vs. longer). We illustrate the value of our granular framework through a systematic review of empirical studies published in PubMed (N = 80 articles). We found that in some cases, particularly for sleep disturbances and sleep duration, our framework identified robust evidence for associations with affect that are separable by domain, method, and timescale. However, in most other cases, evidence was either inconclusive or too sparse, resulting in no clear patterns. Our review did not find support for granular bidirectionality between sleep and affect. We suggest a roadmap for future studies based on gaps identified by our review and discuss advantages and disadvantages of our granular dimensional framework.

Sleep patterns and intraindividual sleep variability in mothers and fathers at 6 months postpartum: a population-based, cross-sectional study

OBJECTIVES

Given that postpartum sleep is an important family process, further investigations including both mothers and fathers are necessary. The present study aimed to describe and compare sleep patterns and intraindividual night-to-night variability in mothers and fathers at 6 months postpartum using subjective and objective sleep measures.

DESIGN

Cross-sectional study.

SETTING

General community-based study in Montreal, QC, Canada.

PARTICIPANTS

Thirty-three couples (mothers and fathers) with no self-reported history of medical and mental health conditions participated in this study.

RESULTS

Parental sleep was measured across 10 consecutive nights using both a daily sleep diary and actigraphy. Results demonstrated that mothers' subjective and objective sleep was more fragmented compared with fathers (shorter longest consecutive sleep duration and more nocturnal awakenings; p<0.001). While mothers and fathers did not differ in their self-reported nocturnal sleep duration (p>0.05), actigraphy indicated that mothers obtained significantly longer nocturnal sleep duration (448.07 min±36.49 min) than fathers (400.96 min±45.42 min; p<0.001). Intraindividual sleep variability was revealed by relatively high coefficients of variation for parents across both subjective and objective indices related to sleep fragmentation (between 0.25 and 1.32). Actigraphy also demonstrated variability by mothers sleeping 6 hours consecutively on less than 3 nights, 27.27% (±22.81), and fathers on less than 6 nights, 57.27% (±24.53), out of 10. Associations were also found between parental sleep and family factors, such as age and infant sleep location (p<0.05).

CONCLUSIONS

These findings advance our knowledge of how sleep unfolds within the family system beyond the early postpartum weeks and/or months. Given the link between disturbed sleep and family functioning, the current research accentuates the importance of examining postpartum sleep patterns and variability in parents.