Adolescents' trajectories of depression and anxiety symptoms prior to and during the COVID-19 pandemic and their association with healthy sleep patterns.

The COVID-19 pandemic has seen a rise in anxiety and depression among adolescents. This study aimed to investigate the longitudinal associations between sleep and mental health among a large sample of Australian adolescents and examine whether healthy sleep patterns were protective of mental health in the context of the COVID-19 pandemic. We used three waves of longitudinal control group data from the Health4Life cluster-randomized trial (N = 2781, baseline Mage = 12.6, SD = 0.51; 47% boys and 1.4% 'prefer not to say'). Latent class growth analyses across the 2 years period identified four trajectories of depressive symptoms: low-stable (64.3%), average-increasing (19.2%), high-decreasing (7.1%), moderate-increasing (9.4%), and three anxiety symptom trajectories: low-stable (74.8%), average-increasing (11.6%), high-decreasing (13.6%). We compared the trajectories on sociodemographic and sleep characteristics. Adolescents in low-risk trajectories were more likely to be boys and to report shorter sleep latency and wake after sleep onset, longer sleep duration, less sleepiness, and earlier chronotype. Where mental health improved or worsened, sleep patterns changed in the same direction. The subgroups analyses uncovered two important findings: (1) the majority of adolescents in the sample maintained good mental health and sleep habits (low-stable trajectories), (2) adolescents with worsening mental health also reported worsening sleep patterns and vice versa in the improving mental health trajectories. These distinct patterns of sleep and mental health would not be seen using mean-centred statistical approaches.

Effects of cognitive behavioural therapy and bright light therapy for insomnia in youths with eveningness: study protocol for a randomised controlled trial.

BACKGROUND: Insomnia and eveningness are common and often comorbid conditions in youths. While cognitive behavioural therapy for insomnia (CBT-I) has been suggested as a promising intervention, it remains unclear whether it is sufficient to also address circadian issues in youths. In addition, despite that light has been shown to be effective in phase-shifting one's circadian rhythm, there has been limited data on the effects of bright light therapy and its combination with CBT-I on sleep and circadian outcomes in youths. The current protocol outlines a randomised controlled trial that examines the efficacy of CBT-I and CBT-I plus bright light therapy (BLT) in reducing insomnia severity, improving mood symptoms and daytime functioning (e.g. sleepiness, fatigue, cognitive function), and improving subjective and objective sleep and circadian measures compared to a waitlist control group. METHODS: We will carry out a randomised controlled trial (RCT) with 150 youths aged 12-24 who meet the criteria of insomnia and eveningness. Participants will be randomised into one of three groups: CBT-I with bright light therapy, CBT-I with placebo light, and waitlist control. Six sessions of CBT-I will be delivered in a group format, while participants will be currently asked to use a portable light device for 30 min daily immediately after awakening throughout the intervention period for bright light therapy. The CBT-I with light therapy group will receive bright constant green light (506 lx) while the CBT-I with placebo light group will receive the modified light device with the LEDs emitting less than 10 lx. All participants will be assessed at baseline and post-treatment, while the two active treatment groups will be additionally followed up at 1 month and 6 months post-intervention. The primary outcome will be insomnia severity, as measured by the Insomnia Severity Index. Secondary outcomes include self-reported mood, circadian, daytime functioning, and quality of life measures, as well as sleep parameters derived from actigraphy and sleep diary and neurocognitive assessments. Objective measures of the circadian phase using dim-light melatonin onset assessment and sleep parameters using polysomnography will also be included as the secondary outcomes. DISCUSSION: This study will be the first RCT to directly compare the effects of CBT-I and BLT in youths with insomnia and eveningness. Findings from the study will provide evidence to inform the clinical management of insomnia problems and eveningness in youths. TRIAL REGISTRATION: ClinicalTrials.gov NCT04256915. Registered on 5 February 2020.

A bidirectional model of sleep and technology use: A theoretical review of How much, for whom, and which mechanisms.

The link between technology and sleep is more complex than originally thought. In this updated theoretical review, we propose a new model informed by the growing body of evidence in the area over the past 10 years. The main theoretical change is the addition of bi-directional links between the use of technology and sleep problems. We begin by reviewing the evidence to date for the originally proposed mechanisms of bright light, arousal, nighttime sleep disruptions, and sleep displacement. Then, in support of the new direction of effect (sleep problems preceding technology use), we propose two new mechanisms: technology before sleep might be used as a time filler and/or as an emotional regulation strategy to facilitate the sleep-onset process. Finally, we present potential moderators of the association between technology and sleep, in recognition of protective and vulnerability factors that may mitigate or exacerbate the effects of technology on sleep and vice versa. The goal of this theoretical review is to update the field, guide future public health messages, and to prompt new research into how much technology and sleep affect each other, for whom it may be problematic, and which mechanisms may explain their association.

Sleepless on the road: Are mothers of infants with insomnia at risk for impaired driving?

Infant sleep problems have been associated with a myriad of adverse child and parent outcomes, yet whether these problems may pose a risk for parents on the road has received little research attention. This study sought to test whether mothers of infants with insomnia are at an elevated risk for vehicular crashes, by comparing their objectively measured driving performance with that of mothers of well-sleeping infants and with that of women without children. Fifty-four women from these three groups completed a simulated driving task. Outcome measures included standard deviation of lateral position, number of lane crossings, standard deviation of speed, average speed and maximum speed. Women additionally reported on their driving behaviour using the Driving Behaviour Questionnaire, and on sleep, sleepiness and insomnia symptoms using 7-day sleep diaries and questionnaires. Mothers of infants with insomnia demonstrated greater lane deviation (Wald = 9.53, p = 0.009), higher maximum speed (Wald = 6.10, p = 0.04) and poorer self-rated driving behaviour (Wald = 7.44, p = 0.02) compared with control groups. Analyses also indicated that driving performance in mothers of infants with insomnia tended to be poorer relative to control groups with the progression of time on task. While further research is needed to assess the scope of these effects, our findings suggest that parents, healthcare providers and policymakers should be aware of the potential consequences of infant sleep problems on road safety, and collaborate to establish strategies to mitigate these risks.

Development of evening sleep homeostatic pressure in early adolescent boys.

The physiological processes governing sleep regulation show maturational changes during adolescent development. To date, data are available to specify when delays in circadian timing occur; however, no longitudinal data exist to characterize the maturation of the accumulation of sleep pressure across the evening. The aim of this longitudinal study was to test whether this change in evening sleep propensity can be identified during early adolescence. Twenty pre-pubescent boys' (Mage = 10.3, SD = 0.4 years) evening sleep homeostats were assessed using a series of sleep latency tests every hour (7:30 p.m. to 3:30 a.m.) at 6-month intervals across four waves. While results revealed shorter sleep onset latencies with increasing wakefulness (p < .001), this effect was not moderated by study wave (p = .79). Evening sleep propensity thus appears to remain stable in boys during early adolescence. Future studies should expand upon these findings by using larger samples of girls as well as boys across an extended age range during the teenage years.

Treating sleep problems in young children: A randomised controlled trial of a group-based, parent-focused behavioural sleep intervention.

This study tested the efficacy of a 5 × 1.5 h/session, group-based, parent-focused, behavioural intervention (BI) targeting sleep problems in preschool children. Parents were randomised to either the BI (N = 62) or care as usual (CAU; N = 66) conditions. Outcomes included sleep, anxiety, behavioural problems, internalising and externalising symptoms, transition to school and academic achievement. Assessments were conducted at pre- and post-BI intervention (in the year prior to formal schooling), and then at follow-ups 1 and 2 in the first year of formal schooling. Relative to the CAU, the BI condition demonstrated significantly greater improvements in sleep, anxiety, behaviour problems and internalising and externalising symptoms from pre-to post-intervention. Improvements in sleep, anxiety, and internalising symptoms were maintained, while behaviour and externalising symptoms were further improved upon at school follow-up 2. For the BI group, improvements in sleep at post-intervention were found to mediate improvements in anxiety, internalising, and externalising symptoms, but not behaviour problems, at school follow-ups 1 and 2. There were no significant effects of condition on school transition or academic outcome measures. The results suggest that the BI is effective for sleep, anxiety, behaviour, internalising and externalising symptoms, but not for school transition or academic outcomes. ANZCTR NUMBER: ACTRN12618001161213.

Technology use as a sleep-onset aid: are adolescents using apps to distract themselves from negative thoughts?

Study Objectives: The aim of this study was to; (1) explore whether adolescents use technology as distraction from negative thoughts before sleep, (2) assess whether adolescents who perceive having a sleep problem use technology as distraction more compared to adolescents without sleep complaints, and (3) collect qualitative information about which devices and apps adolescents use as a distraction. Methods: This study used a mixed-methods cross-sectional design, where 684 adolescents (M = 15.1, SD = 1.2, 46% female) answered both quantitative and qualitative questions about their sleep (perceived sleep problem, sleep onset time (SOT), and sleep onset latency [SOL]) and technology use as distraction from negative thoughts. Results: The majority of adolescents answered "yes" or "sometimes" using technology as a distraction from negative thoughts (23.6% and 38.4%). Adolescents who answered "yes" to using technology as distraction were more likely to report having a sleep problem, longer SOL, and later SOT, compared to adolescents who answered "no". The most popular device to distract was the phone, because of its availability, and the most common apps used for distraction included YouTube, Snapchat, and music apps. Conclusions: This study shows that many adolescents use technology to distract themselves from negative thoughts, which may help them manage the sleep-onset process. Thus, distraction may be one mechanism explaining how sleep affects technology use, rather than vice versa.

Can cry tolerance be increased in mothers of infants with sleep problems, and why does it matter? A quasi-experimental study.

STUDY OBJECTIVES: Infant sleep problems are one of the most common complaints of new parents. Research to date has demonstrated a relationship between low parental cry tolerance and infant sleep problems. The aim of this study was to explore whether three emotion regulation strategies could increase parental cry tolerance. METHODS: This study utilised a quasi-experimental design. We recruited 83 females (Mage= 32, SD= 5.26) comprising 3 groups: mothers of good sleeping infants aged 6-24 months, mothers of poor sleeping infants aged 6-24 months, and good sleeping women aged 23-40 years without children. Participants were instructed to listen to crying audio segments and indicate when they felt the child needed to be tended to (measured in seconds). This crying audio was paired with one of three emotion-regulation strategies (i.e., music, gaming, reappraisal). Each participant completed all 4 cry conditions which were counterbalanced to control for order effects. RESULTS: We found that all three strategies yielded significantly longer reaction times (indicating higher cry tolerance) compared to the control condition (p <.001). We also found that mothers of poor sleepers and good sleeping women benefitted from all three emotion regulation strategies compared to control (p <.001 and p= <.05, respectively). The cry tolerance of mothers of good sleepers, on the other hand, did not differ between the control condition and any of the strategies (all ps >.05). CONCLUSIONS: This demonstrates that cry tolerance can be increased using emotion regulation strategies, such as distraction via music or gaming, and reappraisal. This has clinical implications for families implementing behavioural sleep interventions.

Pediatric sleep: current knowledge, gaps, and opportunities for the future.

This White Paper addresses the current gaps in knowledge, as well as opportunities for future studies in pediatric sleep. The Sleep Research Society's Pipeline Development Committee assembled a panel of experts tasked to provide information to those interested in learning more about the field of pediatric sleep, including trainees. We cover the scope of pediatric sleep, including epidemiological studies and the development of sleep and circadian rhythms in early childhood and adolescence. Additionally, we discuss current knowledge of insufficient sleep and circadian disruption, addressing the neuropsychological impact (affective functioning) and cardiometabolic consequences. A significant portion of this White Paper explores pediatric sleep disorders (including circadian rhythm disorders, insomnia, restless leg and periodic limb movement disorder, narcolepsy, and sleep apnea), as well as sleep and neurodevelopment disorders (e.g. autism and attention deficit hyperactivity disorder). Finally, we end with a discussion on sleep and public health policy. Although we have made strides in our knowledge of pediatric sleep, it is imperative that we address the gaps to the best of our knowledge and the pitfalls of our methodologies. For example, more work needs to be done to assess pediatric sleep using objective methodologies (i.e. actigraphy and polysomnography), to explore sleep disparities, to improve accessibility to evidence-based treatments, and to identify potential risks and protective markers of disorders in children. Expanding trainee exposure to pediatric sleep and elucidating future directions for study will significantly improve the future of the field.

Validation of the Parental Understanding and Misperceptions about BAby's Sleep Questionnaire using auto-videosomnography.

BACKGROUND: Previous studies have suggested that parental cognitions about child's sleep may be an important factor underlying pediatric sleep problems. The current study aimed to (a) develop an assessment tool measuring parental understanding and misperceptions about baby's sleep (PUMBA-Q); (b) validate the questionnaire using self-report and objective sleep measures. METHODS: There were 1,420 English-speaking caregivers (68.0% mothers, 46.8% of children being females, mean age 12.3 months), who has completed online self-reported questionnaires. The PUMBA-Q, which was developed for this study, Dysfunctional Beliefs and Attitudes about Sleep (DBAS) and Maternal Cognitions about Infant Sleep Questionnaire (MCISQ) were included to evaluate participant's thoughts on their own or child's sleep. Insomnia Severity Index (ISI) was collected to access participant's subjective insomnia severity. Brief Infant Sleep Questionnaire-Revised (BISQ-R) was used to assess parental-reported child sleep. Auto-videosomnography was used to record child's sleep. RESULTS: Exploratory factor analysis indicated the best fit with a 4-factor model using 23 items (RMSEA = .039). The four subscales were labeled: (a) Misperceptions about parental intervention; (b) Misperceptions about feeding; (c) Misperceptions about child's sleep; and (d) General anxiety of parents. Internal consistency was adequate (Cronbach's alpha = .86). PUMBA-Q scores were significantly associated with MCISQ (r = .64, p < .01), DBAS (r = .36, p < .01), ISI (r = .29, p < .01), BISQ-R (r = .-49, p < .01), objective child's total sleep time (r = -.24, p < .01) and objective number of parental nighttime visits (r = .26, p < .01). CONCLUSIONS: The results demonstrated that PUMBA-Q 23 is a valid assessment tool for parental cognitions of child sleep. The link between parental cognitions and child sleep highlights the importance of managing parental cognitions about child sleep when treating pediatric sleep problems.

Implementation of Behavioral Interventions for Infant Sleep Problems in Real-World Settings.

OBJECTIVES: To compare the real-world frequency, timing, duration, difficulty, and helpfulness of 3 infant Behavioral Sleep Intervention (BSI) approaches: Unmodified Extinction, Modified Extinction, and Parental Presence and to examine the effectiveness and safety of these approaches by comparing infant sleep, parent sleep, daytime sleepiness, depression, and parent-infant bonding between parents who had and had not implemented these interventions. STUDY DESIGN: Participants were 2090 parents (75% mothers, 79% White/Caucasian) of US infants (49% girls) aged 3-18 months (M = 9.1, SD = 4.1). Parents completed online questionnaires regarding their infant's sleep, their own sleep, daytime sleepiness, depression levels, and parent-infant bonding. Infant sleep was assessed via objective-albeit exploratory-autovideosomnography data obtained from the 14 days prior to survey completion. RESULTS: Sixty-four percent of parents reported implementing BSIs. The average age at intervention was 5.3 months (SD = 2.6). Unmodified and Modified Extinction were rated as significantly more difficult to implement compared with Parental Presence but also as more helpful, shorter, and quicker to show improvements. Infant nighttime sleep was longer and more consolidated in the Unmodified and Modified Extinction groups compared with the Parental Presence and non-BSI groups. No differences were found between BSI groups in parent sleep, sleepiness, depression, or parent-infant bonding. CONCLUSIONS: Implementation of BSIs outside clinical settings is pervasive and occurs earlier than generally recommended. Unmodified and Modified Extinction were associated with longer and more consolidated infant sleep. Despite concerns regarding the potential harm of BSIs, implementation of these approaches was not linked with negative outcomes, providing additional evidence for their safety and effectiveness.

Let's Talk about Sleep Baby: Sexual Activity Postpartum and Its Links with Room Sharing, Parent Sleep, and Objectively Measured Infant Sleep and Parent Nighttime Crib Visits.

The postpartum period may pose a considerable challenge for both parent sleep and sexual activity. This study assessed the links between partnered sexual frequency and satisfaction postpartum and parent sleep, infant sleep, parent nighttime caregiving, and parent-infant room sharing. Participants were 897 parents of infants aged 1-18-months (M = 8.8 ± 4.3, 49% girls). Parents completed an online survey about their sexual frequency and satisfaction, sleep, relationship satisfaction, depression, and demographic characteristics. Infant sleep and parent nighttime crib visits were measured objectively using auto-videosomnography during 2-weeks, with 8,460 nights assessed. Results indicated that the frequency of partnered sexual activity was 3.8 ± 4.2 times per month. Frequency of sexual activity increased with infant age, yet increases beyond the first 6 months postpartum were non-significant. Adjusted GEE modeling revealed that more parent nighttime crib visits were significantly associated with lower sexual frequency, regardless of infant age. Other parent and infant sleep-related factors were not significantly linked with sexual frequency in adjusted models. Moreover, sexual satisfaction was not associated with parent nighttime caregiving, parent or infant sleep, or parent-infant sleeping arrangements in adjusted models, suggesting that it may not be susceptible to the effects of disrupted sleep in the postpartum period. These findings suggest that it is not infant or parent sleep disruption per se, but rather parent nighttime engagement with the infant that is associated with parent sexual activity frequency. Longitudinal investigations are warranted to examine the directional pathways of these links.

What's "app"-ning to adolescent sleep? Links between device, app use, and sleep outcomes.

This study investigated the associations between adolescent evening use of technology devices and apps, night time sleep, and daytime sleepiness. Participants were 711 adolescents aged 12-18 years old (46% Female, Mage = 15.1, SD = 1.2). Time spent using technology devices and apps in the hour before bed, and in bed before sleep onset, was self-reported. Participants additionally completed a questionnaire about their sleep on school nights and next day sleepiness. In the hour before bed, 30 min of phone use was associated with a 9-min delay in bedtimes. Thirty minutes spent using laptops, gaming consoles, and watching YouTube was associated with later lights out times of 9 min, ∼16 min and ∼11 min respectively, while watching TV was associated with a 9 min earlier lights out times. Using gaming consoles and watching YouTube were associated with greater odds of receiving insufficient sleep (≤7 h TST). In bed before sleep onset, 30 min spent using laptops, phones, iPad/tablets, and watching YouTube were linked with later lights out times of ∼7 min for phones and laptops, 9 min for iPad/tablets, and ∼13 min for YouTube. Watching Netflix was associated with greater daytime sleepiness. YouTube at this time point was associated with increased odds of sleeping ≤7 h on school nights. Adolescents are engaging with a wide range of technology devices and apps in the evenings. However, certain devices and apps (e.g., phones, laptops, gaming and YouTube) might lead to more negative sleep outcomes for adolescents on school nights compared to others.

Electric lighting, adolescent sleep and circadian outcomes, and recommendations for improving light health.

Light is a potent circadian entraining agent. For many people, daily light exposure is fundamentally dysregulated with reduced light during the day and increased light into the late evening. This lighting schedule promotes chronic disruption to circadian physiology resulting in a myriad of impairments. Developmental changes in sleep-wake physiology suggest that such light exposure patterns may be particularly disruptive for adolescents and further compounded by lifestyle factors such as early school start times. This narrative review describes evidence that reduced light exposure during the school day delays the circadian clock, and longer exposure durations to light-emitting electronic devices in the evening suppress melatonin. While home lighting in the evening can suppress melatonin secretion and delay circadian phase, the patterning of light exposure across the day and evening can have moderating effects. Photic countermeasures may be flexibly and scalably implemented to support sleep-wake health; including manipulations of light intensity, spectra, duration and delivery modality across multiple contexts. An integrative approach addressing physiology, attitudes, and behaviors will support optimization of light-driven sleep-wake outcomes in adolescents.

Sleep's role in the development and resolution of adolescent depression.

Two adolescent mental health fields - sleep and depression - have advanced largely in parallel until about four years ago. Although sleep problems have been thought to be a symptom of adolescent depression, emerging evidence suggests that sleep difficulties arise before depression does. In this Review, we describe how the combination of adolescent sleep biology and psychology uniquely predispose adolescents to develop depression. We describe multiple pathways and contributors, including a delayed circadian rhythm, restricted sleep duration and greater opportunity for repetitive negative thinking while waiting for sleep. We match each contributor with evidence-based sleep interventions, including bright light therapy, exogenous melatonin and cognitive-behaviour therapy techniques. Such treatments improve sleep and alleviate depression symptoms, highlighting the utility of sleep treatment for comorbid disorders experienced by adolescents.

A randomised controlled dismantling trial of sleep restriction therapies for chronic insomnia disorder in middle childhood: effects on sleep and anxiety, and possible contraindications.

Sleep restriction therapies likely drive improvement in insomnia in middle childhood via increases in homeostatic sleep pressure (e.g., evening sleepiness). Increased evening sleepiness may also dampen comorbid anxiety symptoms; and reduced wakefulness in bed may reduce worry. However, sleep restriction therapies have never been evaluated as a standalone intervention in this population. The mechanism of action needs testing, as do effects on anxiety, and cognitive performance and parasomnias (possible contraindications). This randomised controlled trial evaluated the efficacy of two "doses" of sleep restriction therapy (sleep restriction therapy, bedtime restriction therapy), compared to a control condition (time in bed regularisation). A total of 61 children (mean [SD, range] age 9.1 [2.1, 6-14] years; 54% female) with chronic insomnia disorder received two weekly 60-min treatment sessions with a psychologist. Sleep, sleepiness, anxiety, worry, cognitive performance, and parasomnias were measured pre-treatment, across treatment, and at 4-weeks post-treatment. Both the sleep and bedtime restriction groups experienced reductions in total sleep time (d = 1.38-2.27) and increases in evening sleepiness (d = 1.01-1.47) during the 2-week treatment, and improvements in insomnia (i.e., sleep onset latency; d = 1.10-1.21), relative to the control group. All groups reported improved anxiety and worry, yet there were no differences between the control and restriction groups (all p > 0.658). Time in bed increased at the 1-month follow-up, and benefits to sleep and insomnia were maintained. There were no adverse effects on cognitive functioning (all p > 0.259), nor parasomnia occurrence (all p > 0.740). These results suggest that sleep restriction therapies are brief, yet effective, standalone interventions for insomnia in middle childhood, and improvements are likely due to increased sleepiness, not sleep regularisation.

Sleep and physical activity - the dynamics of bi-directional influences over a fortnight.

STUDY OBJECTIVES: The day-to-next day predictions between physical activity (PA) and sleep are not well known, although they are crucial for advancing public health by delivering valid sleep and physical activity recommendations. We used Big Data to examine cross-lagged time-series of sleep and PA over 14 days and nights. METHODS: Bi-directional cross-lagged autoregressive pathways over 153,154 days and nights from 12,638 Polar watch users aged 18-60 years (M = 40.1 SD = 10.1; 44.5% female) were analyzed with cross-lagged panel data modeling (RI-CPL). We tested the effects of moderate-to-vigorous physical activity (MVPA) vs. high intensity PA (vigorous, VPA) on sleep duration and quality, and vice versa. RESULTS: Within-subject results showed that more minutes spent in VPA the previous day was associated with shorter sleep duration the next night, whereas no effect was observed for MVPA. Longer sleep duration the previous night was associated with less MVPA but more VPA the next day. Neither MVPA nor VPA were associated with subsequent night's sleep quality, but better quality of sleep predicted more MVPA and VPA the next day. CONCLUSIONS: Sleep duration and PA are bi-directionally linked, but only for vigorous physical activity. More time spent in VPA shortens sleep the next night, yet longer sleep duration increases VPA the next day. The results imply that a 24-h framing for the interrelations of sleep and physical activity is not sufficient - the dynamics can even extend beyond, and are activated specifically for the links between sleep duration and vigorous activity. The results challenge the view that sleep quality can be improved by increasing the amount of PA. Yet, better sleep quality can result in more PA the next day.

Wi-Fi off, devices out: do parent-set technology rules play a role in adolescent sleep?

There is limited evidence surrounding the relationship between parent-set technology rules and adolescent sleep. This study had two aims: 1) to investigate the relationship between presence of and compliance to parent-set technology rules and adolescent sleep outcomes and daytime sleepiness; 2) to investigate if compliance, non-compliance, or the absence of rules could moderate the relationship between Fear of Missing Out (FoMO) and Bedtime Procrastination (BtP) on sleep outcomes and daytime sleepiness. A total of 711 adolescents aged 12-18 years old (46% Female, M age  = 15.1, SD = 1.2) were recruited through secondary schools in South Australia. Participants completed a survey containing self-report measures about their sleep, daytime sleepiness, FoMO, BtP, the presence/absence of technology rules in their house, and their compliance to these rules. The study design was cross sectional. Results indicated that the presence of a parent-set technology rule was associated with earlier bedtimes regardless of compliance. Earlier lights out times and increased sleep duration were observed in adolescents who always complied to their rules compared to those who did not comply or did not have parent-set technology rules. BtP and FoMO were associated with later bedtimes, later lights out times, longer sleep onset latency, shorter sleep duration, and more daytime sleepiness. However, parent-set rules did not moderate the links between BtP/FoMO and adolescent sleep. Whilst longitudinal investigations are warranted to examine the directionality of these relationships, the present study suggests that parent-set technology rules may play an important role in protecting adolescent sleep.

Understanding Sleep-Wake Behavior in Late Chronotype Adolescents: The Role of Circadian Phase, Sleep Timing, and Sleep Propensity.

Background: Adolescents with a late chronotype are at greater risk for mood disorders, risk-taking behaviors, school absenteeism, and lower academic achievement. As there are multiple causes for late chronotype, the field lacks studies on the relationship between mood, circadian phase, and phase angle of entrainment in late chronotype adolescents. Three objectives guide this explorative study: (1) to describe sleep, circadian phase, and phase angle of entrainment in late chronotype adolescents, (2) to explore how different levels of lateness are associated with sleep quality, sleep propensity, and mood, and (3) to investigate the influence of circadian phase on bedtime choice and sleep duration. Methods: Baseline data from 19 male adolescents (M = 16.4 ± 1.0 yrs), who were part of a larger intervention trial, were analyzed. Chronotype was measured with the Munich Chronotype Questionnaire, circadian timing via dim light melatonin onset (DLMO), and sleep habits with a 7-day sleep log. Further questionnaires assessed daytime sleepiness, sleep quality, and mood. Evening sleepiness and sustained attention were used as a proxy for evening sleep propensity. Results: On school nights, sleep duration averaged 7.78 h (±1.65), and 9.00 h (±1.42) on weekend nights. Mean DLMO was observed at 23.13 h (± 1.65), with a weekend phase angle of entrainment of 2.48 h. Regression fittings revealed a tendency for shorter phase angles with delayed DLMOs. Further analysis with chronotype subgroups revealed that this was only true for light and moderate late types, whereas extreme late types showed wide phase angles. Even though daytime sleepiness and sleep duration did not differ between subgroups, mood and sleep quality declined as lateness increased. Extreme late chronotypes experienced higher evening sleepiness, while slight late chronotypes showed higher evening attention. Chronotype but not DLMO predicted bedtime on school- and particularly weekend-nights. Conclusions: Our findings suggest that with increasing lateness, the likelihood of experiencing poor sleep quality and mood disorders increases. As DLMO did not predict bedtime, our data indicate that the factors contributing to a late chronotype are versatile and complex, particularly for extreme late types. Further studies involving a larger and gender-balanced sample are needed to confirm findings.