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.

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.

Low-intensity scheduled morning exercise for adolescents with a late chronotype: a novel treatment to advance circadian phase?

Study Objectives: During adolescence, an interplay between biological and environmental factors leads to constrained sleep duration and timing. The high prevalence of sleep deprivation during this developmental period is a public health concern, given the value of restorative sleep for mental, emotional, and physical health. One of the primary contributing factors is the normative delay of the circadian rhythm. Therefore, the present study aimed to evaluate the effect of a gradually advanced morning exercise schedule (30 min shift each day) completed for 45 min on 5 consecutive mornings, on the circadian phase and daytime functioning of adolescents with a late chronotype, compared with a sedentary control group. Methods: A total of 18 physically inactive male adolescents aged 15-18 years spent 6 nights at the sleep laboratory. The morning procedure included either 45 min walking on a treadmill or sedentary activities in dim light. Saliva dim light melatonin onset, evening sleepiness, and daytime functioning were assessed during the first and last night of laboratory attendance. Results: The morning exercise group had a significantly advanced (earlier) circadian phase (27.5 min ± 32.0), while sedentary activity resulted in a phase delay (-34.3 min ± 53.2). Morning exercise also led to higher evening sleepiness in the earlier hours of the night, but not at bedtime. Mood measures improved slightly in both study conditions. Conclusions: These findings highlight the phase-advancing effect of low-intensity morning exercise among this population. Future studies are needed to test the transference of these laboratory findings to adolescents' real life.

Homeostatic response to sleep restriction in adolescents.

The high prevalence of chronic sleep restriction in adolescents underscores the importance of understanding how adolescent sleep is regulated under such conditions. One component of sleep regulation is a homeostatic process: if sleep is restricted, then sleep intensity increases. Our knowledge of this process is primarily informed by total sleep deprivation studies and has been incorporated in mathematical models of human sleep regulation. Several animal studies, however, suggest that adaptation occurs in chronic sleep restriction conditions, showing an attenuated or even decreased homeostatic response. We investigated the homeostatic response of adolescents to different sleep opportunities. Thirty-four participants were allocated to one of three groups with 5, 7.5, or 10 h of sleep opportunity per night for five nights. Each group underwent a protocol of nine nights designed to mimic a school week between two weekends: two baseline nights (10 h sleep opportunity), five condition nights (5, 7.5, or 10 h), and two recovery nights (10 h). Measures of sleep homeostasis (slow-wave activity and slow-wave energy) were calculated from frontal and central EEG derivations and compared to predictions derived from simulations of the homeostatic process of the two-process model of sleep regulation. Only minor differences were found between empirical data and model predictions, indicating that sleep homeostasis is preserved under chronic sleep restriction in adolescents. These findings improve our understanding of effects of repetitive short sleep in adolescents.

Sleep duration and mood in adolescents: an experimental study.

STUDY OBJECTIVES: This study examines the relationship between experimentally manipulated sleep duration and mood in adolescents. METHODS: Thirty-four adolescents (20 male), aged 15-17 years, lived in a sleep laboratory for 10 days and 9 nights. They were allocated to one of three sleep "doses" for five consecutive nights for 5, 7.5, or 10 h sleep opportunity per night. Two baseline nights and two recovery nights entailed 10 h sleep opportunity per night. Mood was measured every 3 h during wake using unipolar visual analogue scales measuring the mood states "depressed," "afraid," "angry," "confused," "anxious," "happy," and "energetic." RESULTS: Mixed models analyses with post hoc comparisons revealed that participants in the 5-h group, but not the 7.5- or 10-h groups, reported being significantly more depressed, angry, and confused during sleep restriction than at baseline. Adolescents were significantly less happy and energetic during sleep restricted to 5 h and significantly less energetic during sleep restricted to 7.5 h. When adolescents had 10 h sleep opportunities their happiness significantly increased. No statistically significant effects of sleep restriction were found for fear or anxiety, although small-to-moderate effects of sleep restricted to 5 or 7.5 h were found. Two nights of recovery sleep was not sufficient to recover from increased negative mood states for the 5-h group, although recovery occurred for positive mood states. CONCLUSIONS: Given the prevalence of insufficient sleep and the rising incidence of mood disorders and dysregulation in adolescents, these findings highlight the importance of sufficient sleep to mitigate these risks.

Interpretation bias in social anxiety: A systematic review and meta-analysis.

BACKGROUND: Interpretation bias, which involves interpreting ambiguous social events negatively and catastrophising even mildly negative social events, has been suggested as a key maintenance factor of Social Anxiety Disorder. Although some individual studies and narrative reviews have demonstrated a role for negative interpretation bias in social anxiety (disorder), findings have been mixed. Given the lack of a quantitative synthesis of the evidence, the current systematic review and meta-analysis examined the strength of the relationship between interpretation bias and social anxiety. It also investigated potential moderators of this relationship (i.e., types of measures and stimuli, samples, and study designs). METHODS: Five databases (PsycINFO, PubMed, Medline, Scopus, and CINAHL) were searched. Of 46 studies identified, 44 were suitable for meta-analysis (N = 3859). RESULTS: There was a large effect for the relationship between social anxiety and interpretation bias (g = 0.83). Types of measures (subjective versus objective) and stimuli (verbal versus visual) were identified as significant moderators, with subjective measures and verbal stimuli particularly adept at capturing interpretation bias in socially anxious individuals. LIMITATIONS: The effect sizes displayed significant heterogeneity between studies, which likely reflects some publication bias, and thus, the overall effect size may be inflated. CONCLUSION: Findings may help to refine clinical models and interventions for Social Anxiety Disorder, which in turn may maximise evidence-based interventions that target negative interpretation bias in this disorder.

The relationship between sleep duration and mood in adolescents: A systematic review and meta-analysis.

Insufficient sleep has been argued to result in deleterious changes to mood in adolescents and offers promise as a modifiable risk factor. A systematic review of the literature regarding sleep duration and mood in adolescents was conducted using the academic databases PsycINFO, PubMed, Medline, Scopus, and EMBASE to identify relevant literature. Seventy-four studies, including 361,505 adolescents were sourced out of the 1534 references identified, 73 of which were appropriate for meta-analysis. Pooled results indicated that less sleep was associated with a 55% increase in the likelihood of mood deficits. Positive mood showed the largest relationship with sleep duration, followed by anger, depression, negative affect and anxiety. Effect sizes also varied according to study design, how sleep was operationalised, and geographical region, but not according to the inclusion of covariates. Sleep duration has a significant negative impact on a range of mood states in healthy adolescents. These effects were witnessed across all geographical regions, highlighting that sleep is a universal and modifiable risk factor for preventing mood deficits in this at-risk population.

The roles of repetitive negative thinking and perfectionism in explaining the relationship between sleep onset difficulties and depressed mood in adolescents.

OBJECTIVE: The present study investigated the relationship between difficulty initiating sleep and depressed mood and whether it is mediated by repetitive negative thinking. A moderating role of perfectionism was also examined. METHODS: We surveyed 393 adolescents aged 14 to 20 years (M = 17.32, SD = 1.90) via an online questionnaire that assessed difficulty initiating sleep, repetitive negative thinking, perfectionism, and depressed mood. RESULTS: Results indicated that repetitive negative thinking fully mediated the relationship between difficulty initiating sleep and depressed mood. In addition, this relationship was moderated by perfectionism, specifically, the relationship between repetitive negative thinking and depressed mood was stronger among more perfectionistic adolescents. CONCLUSIONS: These findings highlight that repetitive negative thinking is significantly associated with both difficulty initiating sleep and depressed mood, supporting the conceptualization of repetitive negative thinking as a transdiagnostic process. Further, individual differences in perfectionism may amplify the relationship between repetitive negative thinking and mood. The role of repetitive negative thinking and perfectionism in explaining the link between sleep onset problems and depressed mood has important clinical implications through providing possible treatment targets.

How internal and external cues for bedtime affect sleep and adaptive functioning in adolescents.

OBJECTIVE: To determine whether the main reason for bedtime is associated with sleep and adaptive functioning in adolescents. METHODS: Participants were 1374 adolescents (X age = 16.8 years, SD = 0.58; 33.6% male) from Helsinki, Finland. Adolescents completed a questionnaire battery including the Munich Chronotype Questionnaire, Strengths and Difficulties Questionnaire, Beck Depression Inventory, and items drawn from the School Sleep Habits Survey, and the Pittsburgh Sleep Quality Index. RESULTS: On school nights, adolescents whose parents set their bedtime, and those who went to bed when they were tired went to bed earlier, obtained more sleep and had earlier midpoint of sleep than adolescents who went to bed when they have finished messaging/socializing or when their television show had finished. Adolescents who went to bed when they had finished their homework had sleep that fell in between these groups. On weekends, adolescents whose parents set their bedtime went to bed earlier and had an earlier midpoint of sleep. However, there were no differences between groups in terms of sleep duration once the need to rise for school in the morning was removed. Adolescents who went to bed on school nights when they were tired or once their homework was finished had better adaptive functioning. CONCLUSIONS: These results provide support for two very different approaches to help optimize the sleep of adolescents: either by implementing parental regulation of bedtimes across adolescence, or by encouraging adolescents to use their bodily cues to indicate when it is time for bed, rather than relying on an external cue.

Adolescent sleep restriction effects on cognition and mood.

Adolescents throughout the world do not obtain adequate sleep. A recent proliferation of experimental and quasi-experimental studies has considerably clarified the relationships between sleep loss and neurobehavioral function suggested by earlier epidemiological and cross-sectional studies. These new studies concur in finding that multiple successive nights of restricted sleep can impair multiple cognitive and affective functions. These effects cumulate from night to night, may not fully recover after weekend recovery sleep and may even be compounded by re-exposure to sleep restriction. An hour long afternoon nap reduces sleepiness in addition to improving vigilance, memory encoding and mood without interfering with nocturnal sleep when the latter is shortened. However, this does not detract from the point that adolescents require approximately 9h of sleep per night for optimal neurobehavioral function, a message that more need to embrace.

Children's sleep and health: A meta-review.

Sleep is essential for children's health and well-being. Characteristics of children's sleep such as sleep duration, timing, quality and variability are increasingly being associated with a wide range of health outcomes. The purpose of this study is to conduct a meta-review (systematic review of systematic reviews) to examine the relationship between sleep and health in children. A systematic search of four electronic databases (Medline, PsychInfo, Scopus, and Embase) was conducted to identify systematic reviews that examine the association between characteristics of children's sleep and health. Key findings, as well as areas in need of further research were synthesised descriptively. A total of 39 systematic reviews were identified for inclusion, covering areas of cognition, psychosocial health, cardiometabolic health, adiposity and other outcomes such as musculoskeletal pain. There is substantial and consistent evidence relating sleep duration to adiposity and emotional outcomes. The relationships between sleep quality and timing and blood lipids and glycaemic control merit further research. Links between sleep and metabolic syndrome in children appear to be weak and inconsistent. Key areas identified in need for further research included studies that objectively assess children's sleep and move beyond cross-sectional study designs and consider characteristics of sleep other than duration. It was also noted that covariates applied across studies varied considerably and the issue of residual confounding was raised in a number of reviews. Lastly, all reviews reported studies adopted a traditional approach of examining only one aspect of children's sleep. Systematic reviews support the notion that sleep is important for children's health. However, further studies that objectively assess sleep and consider characteristics of sleep other than duration and outcomes other than adiposity are needed. An understanding of sleep as a multidimensional construct and as a component of the 24-h d, is also needed to better understand the relationship between sleep and health in children.

Reliability of sleep spindle measurements in adolescents: How many nights are necessary?

Evidence of night-to-night variation in adolescent sleep spindle characteristics is lacking. Twelve adolescents (M = 15.8 ± 0.8 years, eight males) participated in a laboratory study involving 9 nights with 10 hr sleep opportunity. Sleep electroencephalograph was analysed and intra-class coefficients calculated to determine the reliability of sleep spindles across multiple nights of recording. Slow spindle amplitude and fast spindle density, duration and amplitude characteristics all had acceptable reliability within a single night of sleep recording. Slow spindle density and duration measurements needed a minimum of 4 and 2 nights, respectively, for reliable estimation. Theoretical and methodological implications are discussed.

Pediatric motor activity during sleep as measured by actigraphy.

Study Objectives: Provide actigraphic reference values for motor activity during sleep for children and adolescents ages 8-17 years. Methods: Participants were 671 healthy community-dwelling children and adolescents (52% female, mean age 13.5 + 2.4 years) from the United States (64%) and Australia (36%). All participants wore an Ambulatory-Monitoring Inc. (AMI, Ardsley, NY) actigraph on their nondominant wrist for ≥5 nights and completed daily sleep diaries. Actigraphy data were scored with standard methods and a validated algorithm. Reference values were calculated for three outcome variables: percent sleep (sleep minutes/sleep period), mean activity count (average activity count over the sleep period), and restlessness measured by the activity index (% of epochs in sleep period > 0). Between-group differences were examined for sex and age group. In addition, changes to activity level across the sleep period were explored. Results: All participants had a minimum of three scorable nights of data, with 95% having at least five scorable nights. Reference values are presented by age group and sex, and reference percentiles are provided. Boys were found to have more activity in sleep across the three outcome variables. Age differences were also found for the three outcomes, but a consistent pattern was not detected across variables. Conclusions: This study is the first to examine motor activity from actigraphy in a large sample of healthy community-dwelling children and adolescents. Reference tables and percentiles, as well as sample actigrams highlighting different outcomes, are provided for clinicians and researchers who utilize actigraphy in pediatric populations.

REM sleep fragmentation associated with depressive symptoms and genetic risk for depression in a community-based sample of adolescents.

INTRODUCTION: Fragmented REM sleep may impede overnight resolution of distress and increase depressive symptoms. Furthermore, both fragmented REM and depressive symptoms may share a common genetic factor. We explored the associations between REM sleep fragmentation, depressive symptoms, and a polygenic risk score (PRS) for depression among adolescents. METHODS: About 161 adolescents (mean age 16.9 ±â€¯0.1 years) from a birth cohort underwent a sleep EEG and completed the Beck Depression Inventory-II the same day. We calculated PRSes for depressive symptoms with PRSice 1.25 software using weights from a recent genome-wide association study for dimensions of depressive symptoms (negative emotion, lack of positive emotion and somatic complaints). REM fragmentation in relation to entire REM duration was manually calculated from all REM epochs. REM latency and density were derived using SomnoMedics DOMINO software. RESULTS: PRSes for somatic complaints and lack of positive emotions were associated with higher REM fragmentation percent. A higher level of depressive symptoms was associated with increased percent of REM fragmentation and higher REM density, independently of the genetic risks. Belonging to the highest decile in depressive symptoms was associated with a 2.9- and 7.6-fold risk of belonging to the highest tertile in REM fragmentation and density. In addition, higher PRS for somatic complaints had an independent, additive effect on increased REM fragmentation. LIMITATION: A single night's sleep EEG was measured, thus the night-to-night stability of the REM fragmentation-depressive symptom link is unclear. CONCLUSION: Depressive symptoms and genetic risk score for somatic complaints are independently associated with more fragmented REM sleep. This offers new insights on the quality of sleep and its relation to adolescents' mood.

Variability of the cortisol awakening response and morning salivary oxytocin in late adolescence.

Exogenously administered oxytocin interacts with the hypothalamic-pituitary-adrenal (HPA) axis to modulate endogenous cortisol levels, suggesting a synergistic role for these two hormones in the response to stress, cognitive performance and the development of psycho-behavioural disorders. The cortisol awakening response (CAR) is considered a reliable measure of HPA axis function in humans. However, the CAR appears to vary considerably from day to day and may be strongly influenced by the anticipated demands of the day ahead. The level of variation intrinsic to the CAR is unclear because few studies have examined the CAR in the absence of daily environmental variation. It is not known whether oxytocin has a similar or complementary awakening response. Therefore, over three consecutive days, we examined 12 adolescents (aged 15-17 years) in a highly-controlled sleep laboratory. Saliva was collected on days 4-6 of a 9-day laboratory visit. Cortisol and oxytocin levels were determined by an enzyme-linked immunosorbent assay from saliva sampled at 0, 15, 30 and 45 minutes, and 8 and 12 hours post-awakening. CAR magnitude varied between days and was associated with sleep duration and pre-awakening sleep stage. Conversely, oxytocin levels dropped dramatically in the first 15 minutes post-awakening and were highly consistent across participants and days. Older participants had higher awakening oxytocin concentrations. Although cortisol increases and oxytocin rapidly declines upon awakening, their diurnal variation does not appear to be related at basal, peripheral levels, consistent with a previous finding that exogenously administered oxytocin only modulates cortisol under conditions of stress.

Sleep spindles in adolescence: a comparison across sleep restriction and sleep extension.

BACKGROUND: The tendency for adolescents to have restricted sleep has been examined in numerous studies; however, the impact of sleep restriction on adolescents' neural activity during sleep (measured by electroencephalography (EEG)) is less extensively researched, particularly regarding sleep spindles. METHODS: In this experimental study, 34 adolescents attended a 10-day laboratory study where they received five consecutive nights of either 5 h, 7.5 h or 10 h of sleep opportunity, with one adaptation, one baseline and two recovery nights of 10 h of sleep opportunity before and after the experimental phase. RESULTS: Both within- and between-subjects effects were observed for fast sleep spindle characteristics of density, duration and amplitude. Overall, when experiencing severe sleep restriction, fast spindles in adolescents were lower in amplitude and longer in duration. Sex differences were also seen for fast spindle amplitude. CONCLUSIONS: This investigation adds to the knowledge in this field by investigating specific sleep spindle characteristics in the context of experimentally manipulated sleep. Sleep restriction is highly prevalent among adolescents. These findings indicate that chronic sleep restriction has an impact on brain activity related to sleep spindles.

Sleep duration and risk-taking in adolescents: A systematic review and meta-analysis.

Risk-taking is associated with increased morbidity and mortality among adolescents, with insufficient sleep a potential factor contributing to heightened risk-taking propensity in this age group. A systematic review of the evidence examining the relationship between sleep duration and risk-taking in adolescents was conducted using PsycINFO, PubMed, Medline, Scopus, and CINAHL databases. These searches identified 26 studies including 579,380 participants, 24 of which were appropriate for meta-analysis. Pooled results indicated that insufficient sleep was associated with 1.43 [1.26, 1.62] times greater odds of risk-taking. This relationship was witnessed across diverse categories of risk-taking, including alcohol use, drug use, smoking, violent/delinquent behaviour, transport risk-taking/road safety, sexual risk-taking and trait risk-taking. Risk of bias analysis showed that the quality of the included studies was mixed. Further, few studies utilized either longitudinal or experimental designs, thus limiting causal conclusions. These findings highlight the importance of further research to examine the causal relationship between sleep duration and risk-taking and to elucidate the mechanisms that underpin this relationship.

Cognition and objectively measured sleep duration in children: a systematic review and meta-analysis.

BACKGROUND: Sleep recommendations are widely used to guide communities on children's sleep needs. Following recent adjustments to guidelines by the National Sleep Foundation and the subsequent consensus statement by the American Academy of Sleep Medicine, we undertook a systematic literature search to evaluate the current evidence regarding relationships between objectively measured sleep duration and cognitive function in children aged 5 to 13 years. METHODS: Cognitive function included measures of memory, attention, processing speed, and intelligence in children aged 5 to 13 years. Keyword searches of 7 databases to December 2016 found 23 meeting inclusion criteria from 137 full articles reviewed, 19 of which were suitable for meta-analysis. RESULTS: A significant effect (r = .06) was found between sleep duration and cognition, suggesting that longer sleep durations were associated with better cognitive functioning. Analyses of different cognitive domains revealed that full/verbal IQ was significantly associated with sleep loss, but memory, fluid IQ, processing speed and attention were not. Comparison of study sleep durations with current sleep recommendations showed that most children studied had sleep durations that were not within the range of recommended sleep. As such, the true effect of sleep loss on cognitive function may be obscured in these samples, as most children were sleep restricted. CONCLUSIONS: Future research using more rigorous experimental methodologies is needed to properly elucidate the relationship between sleep duration and cognition in this age group.

The role of pre-sleep cognitions in adolescent sleep-onset problems.

STUDY OBJECTIVES: To examine the relationship between pre-sleep cognitions and sleep-onset difficulties in an adolescent sample. METHODS: Participants comprised 385 students (59% male) from grades 9 to 11, aged between 13 and 18 years (M = 15.6, SD = 1.0), from eight co-educational high schools of varied socio-economic status in metropolitan Adelaide, South Australia. The cross-sectional study used a questionnaire battery including the Sleep Anticipatory Anxiety Questionnaire -Adolescent Version (SAAQ-A), completed during school time, followed by eight days of sleep diary completion and wearing wrist actigraphy to obtain subjective and objective sleep onset latency (SOL). RESULTS: Significant relationships were found between somatic arousal (SAAQ-A subscale) and objective SOL and also between sleep-related cognitions (SAAQ-A subscale) and subjective SOL and SOL overestimation (sleep misperception). No relationships were found between subjective SOL and somatic or rehearsal and planning cognitions. Objective SOL was not related to rehearsal and planning and to sleep-related cognition scores, and sleep misperception had no relationship with somatic as well as rehearsal and planning cognition scores. CONCLUSIONS: These findings are not only similar to those in clinical adult populations but also notably different, for example, the lack of association between negative sleep-related pre-sleep cognitions and objective sleep difficulty. The results of this study provide a basis for a more detailed causal study on the existing relationships between negative pre-sleep cognitions and subjective and objective sleep difficulties in this population.

An open trial of bedtime fading for sleep disturbances in preschool children: a parent group education approach.

STUDY OBJECTIVES: To evaluate the efficacy of bedtime fading to reduce sleep disturbances in preschool aged children by using a group parent education format. DESIGN: A repeated-measures design (pretreatment, treatment, post-treatment and two year follow-up). SETTING: Flinders University Child and Adolescent Sleep Clinic, Adelaide, South Australia. PARTICIPANTS: Participants comprised 21 children (M age = 3.0 ± 0.80 years, range = 1.5-4.0 years; 60% girls) identified as having difficulty initiating sleep, night waking, or a combination of both, and their mothers (M age = 36.1 ± 4.2 years). INTERVENTIONS: Mothers attended two group sessions that included basic sleep education (sleep needs, sleep architecture, and sleep homeostasis) and bedtime fading instruction. MEASUREMENTS AND RESULTS: Primary outcome variables were sleep onset latency (SOL), wake after sleep onset (WASO), and bedtime tantrums, and these variables were measured using two week maternal report sleep diaries. Immediate improvements were observed over pretreatment to treatment in average SOL per night (M = 23.2 ± 11.3 min vs. M = 13.0 ± 7.3 min, d = 0.91), average WASO per night (M = 32.4 ± 23.1 min vs. M = 24.0 ± 18.3 min, d = 0.41), and number of bedtime tantrums per week (M = 1.7 ± 3.0 vs. M = 0.4 ± 0.7, d = 0.43). Treatment gains were maintained at two year follow-up. Mothers rated bedtime fading high in terms of usefulness and satisfaction, and they reported that could successfully reimplement the treatment when needed. CONCLUSIONS: Bedtime fading is a brief and promising intervention for pre-schoolers' sleep difficulties. This simple intervention can be easily implemented by parents at home with little instructions, resulting in improvements in sleep and bedtime tantrums.