Sleep in adolescence: Physiology, cognition and mental health

Changes in sleep and activity from age 15 to 17 in students with traditional and college-style school schedules

OBJECTIVES

Sleep duration and physical activity decline with age during adolescence. Earlier school schedules may contribute to these declines. The aim of this longitudinal study was to track changes in sleep and activity of Icelandic youth from primary to secondary school and compare students who enrolled in secondary schools with traditional and college-style schedules.

METHODS

We measured free-living sleep and activity with wrist actigraphy and body composition by dual-energy x-ray absorptiometry in 145 students at age 15 and age 17, when 58% attended schools with college-style scheduling. Differences from 15 to 17 and between students of different school structures were assessed with mixed-effect models.

RESULTS

Actigraphs were worn for 7.1 ± 0.4 nights at 15 and 6.9 ± 0.4 nights at 17. Overall, sleep duration decreased from 6.6 ± 0.7 h/night to 6.2 ± 0.7 h/night from age 15 to 17 (P < .001). Students with traditional schedules reduced school-night sleep duration 26 min/night at follow-up (P< .001), while sleep duration did not change for college-style students. All students went to bed later on school nights at follow-up, but only college-style students rose later. Sleep efficiency and awakenings did not differ by schedule-type. Neither sex changed body fat percentage, but average school-day activity decreased by 19% (P< .001) on follow-up and did not differ by schedule-type.

CONCLUSIONS

Over the 2-year period, adolescents decreased weekly sleep duration and activity, but only those continuing traditional schedules reduced school-night sleep. This suggests greater individual control of school schedule may preserve sleep duration in this age group, which may be beneficial during the transition into adulthood.

Afternoon School Start Times Are Associated with a Lack of Both Social Jetlag and Sleep Deprivation in Adolescents

The delayed circadian timing of adolescents creates a conflict with early school start times (SSTs). We used wrist actimetry to compare sleep parameters and routine nighttime activities in middle school students attending either a morning (0700 to 1200 h) or an afternoon (1230 to 1730 h) school shift. On school days, students from both shifts (n = 21 for morning shift, n = 20 for afternoon shift, ages 12-14 years) had a similar sleep onset, but morning-shift students had an earlier sleep offset and a 1 h 45 min shorter sleep duration than their afternoon peers, who slept the recommended 8 to 10 h of daily sleep. Only morning-shift students had afternoon naps, but this afternoon sleep was not sufficient to overcome sleep deprivation. On weekends, sleep onsets and offsets did not differ between shifts. Because only morning-shift students woke up later and slept longer (2 h 3 min) on weekends, they were also the only ones who experienced social jetlag. Daily surveys on their nighttime (from 1800 to 0600 h) activities indicated there was no difference between shifts in the time spent on leisure or using electronic media during school days, but students from both shifts spent more time in these activities during the weekend. Our study confirms that early SST in adolescents is associated with sleep deprivation and suggests that schedules that start much later than typically considered may be needed to eliminate sleep deprivation in adolescents.

Later School Start Time: The Impact of Sleep on Academic Performance and Health in the Adolescent Population

The crucial role of sleep in physical and mental health is well known, especially during the developmental period. In recent years, there has been a growing interest in examining the relationship between sleep patterns and school performance in adolescents. At this stage of life, several environmental and biological factors may affect both circadian and homeostatic regulation of sleep. A large part of this population does not experience adequate sleep, leading to chronic sleep restriction and/or disrupted sleep–wake cycles. Studies investigating the effects of different sleep–wake schedules on academic achievement showed that impaired sleep quality and quantity are associated with decreased learning ability and compromised daytime functioning. This review focuses on the most recent studies that evaluated the effects of modified school start time on sleep patterns and related outcomes. Moreover, based on the available empirical evidence, we intend to propose a direction for future studies targeted to implement prevention or treatment programs by modifying sleep timing.

How odor cues help to optimize learning during sleep in a real life-setting

Effortless learning during sleep is everybody’s dream. Several studies found that presenting odor cues during learning and selectively during slow wave sleep increases learning success. The current study extends previous research in three aspects to test for optimization and practical applicability of this cueing effect: We (1) performed a field study of vocabulary-learning in a regular school setting, (2) stimulated with odor cues during the whole night without sleep monitoring, and (3) applied the odor additionally as retrieval cue in a subsequent test. We found an odor cueing effect with comparable effect sizes (d between 0.6 and 1.2) as studies with sleep monitoring and selective cueing. Further, we observed some (non-significant) indication for a further performance benefit with additional cueing during the recall test. Our results replicate previous findings and provide important extensions: First, the odor effect also works outside the lab. Second, continuous cueing at night produces similar effect sizes as a study with selective cueing in specific sleep stages. Whether odor cueing during memory recall further increases memory performance hast to be shown in future studies. Overall, our results extend the knowledge on odor cueing effects and provide a realistic practical perspective on it.

Loneliness in the lives of Danish adolescents: Associations with health and sleep

Aims: We examined the relationship between loneliness and health among young adolescents. We also investigated the validity of a single-item measure of loneliness by comparing this to a composite score. Methods: The current data come from a nationally representative sample of 11- to 15-year-old adolescents (N=3305; F=52%) from Denmark collected in 2014 as part of the Health Behaviour in School-aged Children (HBSC) collaborative cross-national survey. Results: A series of binary logistic regressions showed that higher loneliness among adolescents, whether measured using the single- or multi-item measurement, was associated with poorer self-rated health, higher frequency of headache, stomach ache, backache, difficulties sleeping, greater sleep disturbance and more instances of feeling tired in the morning. Those associations were relatively consistent across sex and age groups. Conclusions:Loneliness is associated with poorer self-reported health and sleep problems among young adolescents. Those findings are similar across two measures of loneliness, suggesting robust findings. The development of interventions and health-education efforts to fight loneliness in adolescence is important.

Emotional Awareness Correlated With Number of Awakenings From Polysomnography in Patients With Myalgic Encephalomyelitis/Chronic Fatigue Syndrome-A Pilot Study

INTRODUCTION

Unrefreshing sleep is one of the diagnostic criteria in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), which could be explained by sleep disorders, for example obstructive sleep apnea, reported in our previous study with polysomnography. Our previous findings also indicate difficulties in emotional regulation when measuring alexithymia by TAS-20 (Toronto Alexithymia Scale) and level of emotional awareness by LEAS (Level of Emotional Awareness Scale) in ME/CFS patients. However, the reasons for this are unknown. The purpose of this study was to investigate correlations between data from subjective emotional regulation and polysomnography.

METHODS

Twenty-three ME/CFS patients (5 men and 18 women) of mean age 43, and 30 matched healthy controls (9 males and 21 women) of mean age 45, filled in TAS-20, LEAS, and Hospital Depression and Anxiety Scale (HADS). A polysomnography was performed on patients but not on healthy controls. Thus, values of normal population were used for sleep evaluation in ME/CFS patients.

RESULT

There were significant differences between patients and controls in several aspects of emotional regulation, for example LEAS-self and LEAS-total. Seventy percent of the patients had increased numbers of awakenings (shifts from any sleep stage to awake), 22% had obstructive sleep apneas, and 27% had periodic limb movements. Correlation analysis showed that number of awakenings significantly correlated with LEAS-self and LEAS-total, p < 0.01, respectively. There were no other significant correlations.

CONCLUSION

This pilot study demonstrated significant correlations between reduced emotional awareness and number of awakenings in polysomnography. Future studies with larger cohorts need to be conducted.

Sleep spindle density is associated with worry in children with generalized anxiety disorder and healthy controls

BACKGROUND

Childhood generalized anxiety disorder (GAD), characterized by uncontrollable worry, is associated with long-term psychopathology risk, yet understanding of developmental trajectories is limited. Despite common complaints about sleep, 'macro' sleep abnormalities have not been identified. Emerging findings suggest micro-architectural features of sleep, including sleep spindles, differentiate various psychiatric populations. The current study investigated sleep spindle density during non-rapid eye movement (NREM) sleep among youth with GAD and healthy controls, including relationships with anxiety, worry, global functioning, and subjective sleep quality.

METHODS

58 pre-pubertal children, n = 26 with GAD and n = 32 matched healthy controls, aged 7-11 years (M = 8.86, SD=1.47), completed diagnostic assessments and a week of actigraphy monitoring prior to a night of polysomnography (PSG) either at home or in a sleep laboratory. NREM spindle activity was detected in frontal and central regions.

RESULTS

Sleep spindle activity did not differ based on diagnostic group or sex. Sleep spindles were unassociated with anxiety and sleep quality but showed a significant positive association with worry in all youth. Among youth with GAD, global functioning was negatively associated with spindle density in frontal regions during NREM stage 3. Spindle density was significantly greater during in-lab compared to at-home PSG.

LIMITATIONS

The small sample size and reliance on only one night of PSG necessitate additional studies.

CONCLUSIONS

The identified link between spindle activity and worry in pre-pubertal children highlights a need for investigations on transdiagnostic features of child psychopathology rather than specific disorders. Longitudinal studies are needed to explore spindle characteristics and affective risk across development.

The Moderating Role of Sleep in the Relationship Between Social Isolation and Internalising Problems in Early Adolescence

Social isolation may be a unique risk factor for depression and anxiety in early adolescence. However, optimal sleep may protect adolescents from the emotional sequela of social isolation. The present study aimed to investigate whether sleep moderates the relationship between social isolation and symptoms of anxiety and depression in early adolescence. Five hundred and twenty eight early adolescents (M = 11.18 years, SD = 0.56, range 10-12 years, 51% male) completed online questionnaires assessing social isolation, sleep duration, daytime sleepiness and symptoms of generalised anxiety, social anxiety, separation anxiety and depression. Sleep duration moderated the effect of social isolation on symptoms of generalised anxiety, social anxiety and depression, but not separation anxiety. Daytime sleepiness emerged as an additional sleep-related risk factor in the relationship between social isolation and depressive symptoms. Therefore, sleep may be an important modifiable risk or protective factor to target, in the prevention of depression and anxiety in adolescence.

Association between depressive symptoms and sleep neurophysiology in early adolescence

BACKGROUND

Depression is highly prevalent among adolescents, and depressive symptoms rise rapidly during early adolescence. Depression is often accompanied by subjective sleep complaints and alterations in sleep neurophysiology. In this study, we examine whether depressive symptoms, measured on a continuum, are associated with subjective and objective (sleep architecture and neurophysiology) measures of sleep in early adolescence.

METHODS

High-density sleep EEG, actigraphy, and self-reported sleep were measured in 52 early adolescents (12.31 years; SD: 1.121; 25 female). Depressive symptoms were measured on a continuum using the Center for Epidemiological Studies Depression Scale (CES-D). The association between depressive symptoms and 2 weeks of actigraphy, self-reported sleep, sleep architecture, and sleep neurophysiology (slow wave activity and sigma power) was determined via multiple linear regression with factors age, sex, and pubertal status.

RESULTS

Despite no association between polysomnography measures of sleep quality and depressive symptoms, individuals with more depressive symptoms manifested worse actigraphically measured sleep. Less sleep spindle activity, as reflected in nonrapid eye movement sleep sigma power, was associated with more depressive symptoms over a large cluster encompassing temporal, parietal, and occipital regions. Furthermore, worse subjectively reported sleep quality was also associated with less sigma power over these same areas. Puberty, age, and sex did not impact this association.

CONCLUSIONS

Sleep spindles have been hypothesized to protect sleep against environmental disturbances. Thus, diminished spindle power may be a subtle sign of disrupted sleep and its association with depressive symptoms in early adolescence may signal vulnerability for depression.

Associations of adolescent lifestyle behaviors with body mass index within a nationally representative sample of US adolescents: a quantile regression analysis

OBJECTIVES

The purpose of this study was to examine the associations between lifestyle behavior variables such as physical activity, television watching, computer use, and school night sleep duration with body mass index percentile (BMI%) using quantile regression within a representative sample of adolescents who completed the 2017 US National Youth Risk Behavior Survey.

STUDY DESIGN

The study design was a cross-sectional study.

METHODS

A multistage cluster sampling procedure obtained a representative sample of US adolescents. The number of sampled adolescents submitting questionnaires with BMI% data was 13,146. To examine the associations between lifestyle behaviors and BMI%, simultaneous quantile regression was used.

RESULTS

When relationships were modeled at every 10th percentile, more precise parameter estimates were observed at higher percentiles. Across the interquartile range, physical activity associated with lower BMI% at the 50th and 75th percentiles (b_range = -2.27% to -5.24%, P < 0.05), television watching associated with higher BMI% at the 25th to 75th percentiles (b_range = 2.29%-4.16%, P < 0.05), sleep durations less than 8 h per school night associated with higher BMI% at the 25th and 50th percentile (b_range = 2.81%-8.26%, P < 0.05), and 10 or more hours of school night sleep associated with higher BMI% at the 50th and 75th percentile (b_range = 3.43%-7.53%, P < 0.05).

CONCLUSIONS

Higher levels of physical activity associated with lower BMI% and longer time watching television, school night sleep durations less than 8 h, and school night sleep durations of 10 h or more at higher quantiles associated with higher BMI% in adolescents. Estimates of association were more precise within higher quantiles.

Cutting-edge technology and nocturnal headaches in adolescent smart phone users in Chiang Mai, Thailand

Purpose

Nocturnal headaches among adolescents were reported to be increased with the development of modern technology. The purpose of this paper is to investigate the smartphone electromagnetic radiation related to nocturnal headaches among high school students.

Design/methodology/approach

The time series study of all 12,969 records from 145 high school students Chiang Mai Province was selected from the population in the first phase by setting criteria. The samples completed a headache diary utilizing a smartphone application. The smartphone output power (SOP) was measured and recorded by the smartphone application and transmitted by e-mail to a researcher. The smartphone use, sleep quality, anxiety and depression also were assessed. Data were analyzed using Generalized Estimating Equation adjusting for demographic data, smartphone use, and sleep quality and otherwise.

Findings

The resulted showed the prevalence of repeated headaches to be 13.4 percent, nocturnal headache only 5.3 percent and the strongest effect of day time SOP at a 1.80–1.99×10−5 mW range on nocturnal headaches (ORadj5.18; 95% CI: 3.44–7.81). Meanwhile, Lag_6 of daily SOP exposure produced a nocturnal headache effect in a reverse dose-response manner. Furthermore, the nocturnal headache also had the strongest association with age, internet use and device brand (ORadj2.33; 95% CI: 1.08–5.05, ORadj2.14; 95% CI: 1.07–4.2 and ORadj1.68; 95% CI: 1.1–2.4).

Originality/value

The electromagnetic radiation from a smartphone is the environmental variables influences on headache. The results suggested that there should be limited times for smartphone use and older age to start using a smartphone to prevent headache attacks at night.

The Interactive Effect of Positive Mental Health and Subjective Sleep Quality on Depressive Symptoms in High School Students

Objective/Background: The objective of this study was to observe the effect of positive mental health (PMH) and subjective sleep quality (SQ) on depressive symptoms in high school students. Participants: This cross-sectional study evaluated 2,186 students (55% female and 45% male) with a mean age of 16.8 years (SD ± 0.7) at 20 private high schools in Mexico City. Methods: An electronic survey was used, which included a questionnaire on sleep habits that is a Spanish-language adaptation of Rosenthal's Sleep-Wake Activity Inventory, the Pittsburgh Sleep Quality Index (PSQI), the Morningness-Eveningness Scale for Children and Adolescents (MESC), the combined scales to evaluate positive aspects of mental health, and the Patient Health Questionnaire (PHQ-9). Results: Main and interaction effects of PMH and SQ were observed, demonstrating that students with high-PMH (p ≤ .0001) or good-SQ (p ≤ .0001) had fewer depressive symptoms. Thus, the students with both high-PMH and good-SQ had the lowest depressive symptomatology (p ≤ .01). Conclusion: Depressive symptoms are associated with a combination of sleep quality and positive mental health.

Intraindividual variability of sleep/wake patterns in adolescents with and without attention-deficit/hyperactivity disorder

BACKGROUND

Prior studies examining the sleep of adolescents with and without attention-deficit/hyperactivity disorder (ADHD) have relied on mean values such as average sleep duration, which masks intraindividual variability (IIV). The objective was to investigate whether adolescents with ADHD have greater IIV of sleep/wake patterns than adolescents without ADHD using actigraphy and daily sleep diaries.

METHOD

Adolescents (ages 13.17 ± 0.40 years; 45% female) with (n = 162) and without (n = 140) ADHD were recruited from middle schools at two sites. Participants wore actigraphs and completed sleep diaries for an average of 2 weeks.

RESULTS

Multilevel models were conducted with sex, sleep medication use, ADHD medication use, number of days with data, and social jetlag controlled for in analyses. For actigraphy, adolescents with ADHD had greater variability for time in bed, sleep onset and offset, and wake after sleep onset than adolescents without ADHD. For sleep diary data, adolescents with ADHD had greater variability in bedtime, wake time, sleep duration, sleep onset latency, sleep quality, and night wakings than adolescents without ADHD. Social jetlag was a significant predictor of variability in sleep measures based on both actigraph and daily diaries; however, ADHD status was not associated with social jetlag.

CONCLUSIONS

This is the first study to show that adolescents with ADHD have more variable sleep/wake patterns than their peers using both objective and subjective sleep measures. IIV of sleep/wake patterns may be important for clinicians to assess and monitor as part of treatment. Research is needed to understand the mechanisms underlying increased IIV of sleep/wake patterns in adolescents with ADHD and potential consequences for daytime functioning.

Effects of CDP-choline administration on learning and memory in REM sleep-deprived rats

Cytidine 5-diphosphocholine (CDP-choline) administration has been shown to improve learning and memory deficits in different models of brain disorders. In this study, effects of CDP-choline on the well known negative effects of Rapid Eye Movements (REM) sleep deprivation on learning and memory were investigated. Sleep deprivation was induced by placing adult male Wistar albino rats on 6.5 cm diameter platforms individually for 96 h according to flower pot method. Learning and memory performances were evaluated using Morris Water Maze (MWM) test during the same period of time. Saline or CDP-choline (100 µmol/kg, 300 µmol/kg or 600 µmol/kg) was administered intraperitoneally 30 min prior to the onset of MWM experiments. On completion of behavioral tests, rats were decapitated and hippocampi were assayed for total and phosphorylated Ca²⁺/calmodulin-dependent protein kinase II (tCaMKII and pCaMKII, respectively) and total antioxidant capacity. We observed that while REM sleep deprivation had no effect on learning, it diminished the memory function, which was associated with decreased levels of pCaMKII and total antioxidant capacity in the hippocampus. CDP-choline treatment blocked the impairment in memory function of sleep-deprived rats and, increased pCaMKII levels and total antioxidant capacity. These data suggest that CDP-choline reduces REM sleep deprivation-induced impairment in memory, at least in part, by counteracting the disturbances in biochemical and molecular biological parameters.

Differential and interacting effects of age and sleep restriction on daytime sleepiness and vigilance in adolescence: a longitudinal study

Study Objectives

There is contradictory evidence on whether sleep need decreases across adolescence. We investigated this question longitudinally with a dose-response design to test the effects of varied sleep durations on daytime sleepiness and on vigilance and to test whether these relations change with age across early and mid-adolescence.

Methods

Data from 76 participants who completed at least 2 years of the 3-year study are included in this report. Annually, participants ranging in age from 9.8 to 16.2 years completed three different time in bed (TIB) schedules each consisting of four consecutive nights of 7, 8.5, or 10 hours. Daytime sleepiness (multiple sleep latency test [MSLT]) and vigilance (psychomotor vigilance test [PVT]) were measured on the day following the fourth night of each TIB schedule.

Results

Electroencephalogram (EEG)-measured sleep durations changed linearly with TIB. MSLT-measured daytime sleepiness decreased with longer TIB and increased with age. The TIB and age effects interacted such that the TIB effect decreased with age. PVT performance improved with longer TIB and improved with age, but the benefit that increased TIB conferred on PVT performance did not change with age.

Conclusions

These results seem paradoxical because daytime sleepiness increased but vigilance improved with age. The significant age effect on the relation between TIB and sleepiness compared to the lack of an age effect on the relation between TIB and vigilance performance suggests different rates of maturation in underlying brain systems. We interpret these findings in relation to our model of adolescent brain development driven by synaptic elimination.

A cluster randomized controlled trial of a theory-based sleep hygiene intervention for adolescents

Study Objectives

To use theory to design and evaluate an intervention to promote sleep hygiene and health among adolescents.

Methods

The Theory of Planned Behavior (TPB) and the Health Action Process Approach (HAPA) were used to develop an intervention, which was then evaluated in a cluster randomized trial. Participants were high school students (N = 2,841, M age = 15.12, SD = 1.50). Adolescents in the intervention group received four face-to-face sessions providing behavior change techniques targeting the theoretical determinants of sleep hygiene. Adolescents in the control group only received educational material at the end of the study. The primary outcome was sleep hygiene measured at 1 and 6 months postintervention. A number of secondary outcomes were also measured, including beliefs about sleep, self-regulatory processes, and outcomes related to health and wellbeing.

Results

Sleep hygiene was improved in the intervention group when compared with the control group at both follow-up points (coefficients = 0.16 and 0.19, 95% CIs = 0.12-0.20 and 0.15-0.23 at 1 and 6 months, respectively, for scores on the Adolescent Sleep Hygiene Scale), as were psychosocial and general aspects of health. Mediation analyses suggested that beliefs about sleep hygiene as specified by the TPB, along with self-regulatory processes from HAPA, both mediated the effect of the intervention on outcomes. In turn, the effects of the intervention on sleep hygiene mediated its impact on general health.

Conclusions

Healthcare practitioners might consider intervention programs based on the TPB and the HAPA to improve sleep among adolescents.

Clinical Trial Registration

Clinicaltrials.gov (NCT02551913) https://clinicaltrials.gov/ct2/show/NCT02551913.

Sleep and daytime sleepiness in adolescents with and without ADHD: differences across ratings, daily diary, and actigraphy

BACKGROUND

Children with attention-deficit/hyperactivity disorder (ADHD) experience greater sleep problems than their peers. Although adolescence is generally a developmental period characterized by insufficient sleep, few studies have used a multi-informant, multi-method design, to examine whether sleep differs in adolescents with and without ADHD.

METHODS

Targeted recruitment was used to enroll an approximately equal number of eighth-grade adolescents (mean age = 13 years) with (n = 162) and without ADHD (n = 140). Adolescents and parents completed global ratings of sleep problems; adolescents, parents, and teachers completed ratings of daytime sleepiness. Adolescents wore actigraphs and completed a daily sleep diary for approximately 2 weeks.

RESULTS

Adolescents with ADHD were more likely than adolescents without ADHD to obtain insufficient sleep on school days (per diary) and weekends (per diary and actigraphy). Adolescents with ADHD were also more likely to report falling asleep in class and to have stayed up all night at least twice in the previous 2 weeks (14% and 5% reported all-nighters for ADHD and comparison, respectively). In regression analyses controlling for a number of variables known to impact sleep (e.g. pubertal development, sex, medication use, having an externalizing, anxiety, or depression diagnosis), ADHD remained associated with shorter diary and actigraphy school night sleep duration, adolescent- and parent-reported daytime sleepiness, and parent-reported difficulties initiating and maintaining sleep and total sleep disturbance. Controlling for other variables, the odds of being classified with clinically elevated parent-reported sleep disturbance were 6.20 times greater for adolescents with ADHD.

CONCLUSIONS

Findings provide some of the clearest evidence yet that adolescents with ADHD experience more sleep problems and sleepiness than their peers without ADHD. It may be especially important to assess for sleep problems in adolescents with ADHD and to evaluate whether existing sleep interventions are effective, or can be optimized, for use in adolescents with ADHD who also have sleep problems.

Preschool family irregularity and the development of sleep problems in childhood: a longitudinal study

BACKGROUND

Previous studies have shown that poor family environments are related to more sleep problems; however, little is known about how family irregularity in early life affects the development of sleep problems over childhood using objective sleep measures. The current study tests the hypothesis that early family irregularity contributes to the development of sleep problems.

METHODS

This population-based study comprises 5,443 children from the Generation R Study. Family irregularity was measured with seven maternal-reported questions on family routines when children were 2 and 4 years old. Mothers reported on sleep problems at child age 3, 6, and 10 years, whereas children completed questionnaires on sleep problems at age 10. Additionally, we used tri-axial wrist accelerometers for five nights in 851 children (mean age 11.7 years) to assess sleep objectively.

RESULTS

Family irregularity was associated with more mother- and child-reported sleep problems at ages 3, 6, and 10 years as well as with a shorter sleep duration and later objective sleep onset, but not with sleep efficiency or waking time. The association between family irregularity and multi-informant subjective sleep problems at age 10 years was mediated by mother-reported child psychopathology at age 6 years.

CONCLUSIONS

Our findings show a long-term robust association of preschool family irregularity with more sleep problems during childhood as well as shorter sleep duration and later sleep onset as measured objectively with actigraphy. In part, these sleep problems were associated with family irregularity by way of child psychopathology. These findings suggest that interventions improving preschool family irregularity, which are targeted to reduce child psychopathology, may also impact the development of sleep problems beneficially.

Relationships between Sleep Patterns, Health Risk Behaviors, and Health Outcomes among School-Based Population of Adolescents: A Panel Analysis of the Korean Children and Youth Panel Survey

Sleep patterns among adolescents are related to health outcomes and health risk behaviors. This study aimed to describe sleep patterns of Korean adolescents and to find the association between sleep patterns and health risk behaviors and health outcomes. Using the junior high school students’ panel data (n = 2351, 12–15 years old) from the Korean Children and Youth Panel Survey, this study described the sleep patterns operationalized as rising time, bedtime, and sleep duration both on weekdays and weekends. The relationships of sleep patterns with health outcomes and/or health risk behaviors were tested using mixed effect linear regression for continuous health variables and using mixed effect logit regression for binary health variables. Obesity status, the number of chronic symptoms, self-rated health status, smoking, and alcohol consumption were associated with rising time on weekdays after controlling for gender, living area, and housing type. The same set of variables except for the number of chronic symptoms were associated with bedtime during the weekdays. Sleep duration during the weekdays was associated with obesity status, smoking, and alcohol consumption. Similar patterns of association between sleep pattern variables during the weekends and health-related outcome variables were found, but were less obvious than those for weekdays. Significant relationships between sleep patterns and various health-related variables were found among adolescents in Korea. The results from this study indicate that helping adolescents change their sleeping times as necessary to ensure adequate sleep should be considered important in diminishing health risk behaviors and promoting positive health outcomes.

(Re)Conceptualizing Sleep Among Children with Anxiety Disorders: Where to Next?

Children with anxiety disorders (AD) characteristically complain of sleep problems and the extent to which cognitive behavioral treatments (CBT) for childhood anxiety produce sleep-based improvements is a topic of increasing interest. The current paper reviews available evidence for subjective sleep complaints and objective sleep alterations in children and adolescents with AD, including investigations of potential changes in sleep following anxiety-focused CBT. Despite pervasive complaints of poor sleep, the empirical literature provides minimal evidence for actual sleep-wake alterations in this population of youth and evidence for sleep-based changes following treatment for anxiety is minimal. In line with calls for more comprehensive models of the role of sleep in developmental psychopathology, several fundamental gaps in understanding are described and highlighted as essential avenues for clarifying the nature and consequences of poor quality sleep among youth with clinical levels of anxiety. In a second section of the paper, an emerging body of novel, translational research investigating more intricate sleep-anxiety relationships is introduced with potential implications for both etiological models and treatment design and delivery.

Longitudinal Associations Between Sleep Patterns and Psychiatric Symptom Severity in High-Risk and Community Comparison Youth

OBJECTIVE

Sleep disturbance may be involved in symptom progression across multiple domains of psychopathology and could represent a target for treatment development in youth. Our objective was to identify sleep patterns that longitudinally change in conjunction with psychiatric symptom severity in at-risk youth.

METHOD

The study included 484 Pittsburgh Bipolar Offspring Study (BIOS) youth with at least 2 sleep assessments occurring between 10 and 18 years of age: 267 offspring of parents with bipolar I or II disorder and 217 community comparison offspring. Assessments occurred approximately every 2 years (mean number of assessments, 2.8 ± 0.8; mean follow-up duration, 3.8 ± 1.6 years). Offspring had a range of psychiatric diagnoses at baseline. Multivariate lasso regression was implemented to select offspring-reported sleep patterns associated with changes in five psychiatric symptom measures from baseline through last follow-up (mania, depression, mood lability, anxiety, inattention/externalizing). Analyses accounted for parent psychiatric diagnoses and offspring demographics, psychiatric diagnoses, and medications.

RESULTS

Follow-up duration, baseline socioeconomic status, parental history of bipolar disorder, offspring attention-deficit/hyperactivity disorder, and disruptive behavior disorder, and five sleep patterns were identified as predictors of change in all five psychiatric symptom measures. Decreasing sleep duration, later sleep timing preference, longer sleep latency, increasing nighttime awakenings, and greater sleepiness over follow-up were associated with increasing severity the five psychiatric symptom outcomes over follow-up. These 10 predictors explained 16% of the variance in longitudinal psychiatric symptom change, 33% of which was accounted for by sleep predictors.

CONCLUSION

A constellation of sleep features were associated with psychiatric symptom changes in youth, and may represent viable targets for future interventions.

Short-term prediction of suicidal thoughts and behaviors in adolescents: Can recent developments in technology and computational science provide a breakthrough?

BACKGROUND

Suicide is one of the leading causes of death among adolescents, and developing effective methods to improve short-term prediction of suicidal thoughts and behaviors (STBs) is critical. Currently, the most robust predictors of STBs are demographic or clinical indicators that have relatively weak predictive value. However, there is an emerging literature on short-term prediction of suicide risk that has identified a number of promising candidates, including (but not limited to) rapid escalation of: (a) emotional distress, (b) social dysfunction (e.g., bullying, rejection), and (c) sleep disturbance. However, these prior studies are limited in two critical ways. First, they rely almost entirely on self-report. Second, most studies have not focused on assessment of these risk factors using intensive longitudinal assessment techniques that are able to capture the dynamics of changes in risk states at the individual level.

METHOD

In this paper we explore how to capitalize on recent developments in real-time monitoring methods and computational analysis in order to address these fundamental problems.

RESULTS

We now have the capacity to use: (a) smartphone, wearable computing, and smart home technology to conduct intensive longitudinal assessments monitoring of putative risk factors with minimal participant burden and (b) modern computational techniques to develop predictive algorithms for STBs. Current research and theory on short-term risk processes for STBs, combined with the emergent capabilities of new technologies, suggest that this is an important research agenda for the future.

LIMITATIONS

Although these approaches have enormous potential to create new knowledge, the current empirical literature is limited. Moreover, passive monitoring of risk for STBs raises complex ethical issues that will need to be resolved before large scale clinical applications are feasible.

CONCLUSIONS

Smartphone, wearable, and smart home technology may provide one point of access that might facilitate both early identification and intervention implementation, and thus, represents a key area for future STB research.

Prevalence and determinants of poor quality of sleep among adolescents in rural Puducherry, South India

BACKGROUND

Adolescence is a critical stage of life which is characterized by rapid biological, social and emotional development. India has the highest adolescent population, however, there is paucity of literature reporting the sleep quality among adolescents.

OBJECTIVE

To determine the sleep quality and its associated factors among adolescents residing in selected villages of rural Puducherry.

MATERIALS AND METHODS

A community-based cross-sectional study was conducted among adolescents during March and April 2018. Two out of four villages were randomly selected and all the adolescents were contacted through a household visit and a questionnaire was administered. The semi-structured questionnaire contained socio-demographic details of adolescents and details on living environment. Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI) scale. Sleep quality is expressed as a proportion with a 95% confidence interval (CI). The association of socio-demographic characteristics with poor sleep quality is reported as a prevalence ratio.

RESULTS

The total number of adolescents interviewed was 789. The mean age of the study participants was 14.1 (±2.4) years and the majority, 440 (55.8%) were boys and 684 (86.7%) belonged to a nuclear family. More than a quarter, 210 (26.6%) belonged to the middle class as regards socio-economic status. Environmental assessment of households showed more than half, 456 (57.8%) were staying in a "pucca" house and the majority, 642 (81.4%) had adequate cross ventilation. The prevalence of poor quality of sleep among the adolescents was 2.5% (95% CI: 1.6%-3.9%). It was found that higher educational level [adjusted prevalence ratio (aPR) - 3.43] and belonging to higher socio-economic class (aPR - 5.48) were found to be significant determinants for poor quality of sleep among adolescents.

CONCLUSION

The current study found that only 2.5% of the adolescents have poor sleep quality. Adolescents with higher educational level and higher socio-economic status were more prone to have poor quality of sleep.

Sleep Timing in Patients with Precocious and Delayed Pubertal Development

Previous studies have reported a shift in the timing of sleep during adolescence toward a later time. To date, it is unclear whether hormonal changes during puberty might contribute to this change in sleeping behavior. We systematically assessed pubertal development and sleep timing in a cross-sectional case-control study in girls with precocious (n = 42) and boys with delayed pubertal development (n = 19). We used the Munich ChronoType Questionnaire and the Children’s ChronoType Questionnaire to assess sleep timing in patients and age- and sex-matched controls (n = 309) and used the midpoint of sleep on free days, corrected for potential sleep debt accumulated during the school week, as a marker for sleep timing. Compared to the controls, girls with central precocious puberty showed a delay in sleep timing of 54 min, and girls with premature pubarche slept on average 30 min later. Male adolescents with delayed pubertal development showed an average sleep midpoint that was 40 min earlier compared to the control group. The results of this pilot study suggest an association between pubertal onset and shifts in sleep timing, which is a novel finding in human sleep behavior. Prospective studies in larger cohorts will be needed to examine the robustness and generalizability of the findings.

"Let's talk about sleep": a qualitative examination of levers for promoting healthy sleep among sleep-deprived vulnerable adolescents

OBJECTIVE

Deficient sleep is highly prevalent in disadvantaged adolescents and contributes to a range of adverse health and behavioral outcomes. We examined mediating mechanisms and strategies that adolescents adopt to improve sleep, and possible levers for promoting sleep in this population.

METHODS

We conducted three focus groups (N = 27 total, age 14-18 years) in adolescents living in low- and middle-income racially/ethnically diverse neighborhoods of Boston, Massachusetts. Participants completed a survey on their sleep and health habits prior to the moderator-led discussions. Discussions were audio-recorded, transcribed, and thematically analyzed.

RESULTS

The study population did not meet the minimum sleep recommendations, and we found a high prevalence of "social jet-lag." We also identified a disconnect between the acknowledgment of the importance of sleep and actual behavior, especially for electronic use. Phone use and screen time were the most commonly cited barriers to a good night's sleep, along with caffeine consumption, which was also high in this sample. There was also a general lack of awareness of sleep hygiene practices and recommendations. Participants reported regulating food intake and physical activity, using allopathic sleep aids, creating a comfortable sleeping environment, and a routine as some strategies to improve sleep.

CONCLUSION

Results from this study suggest facilitating the linkage between participant-generated mediating factors and strategies for better-designed interventions. These include making the negative impact of sleep on health more explicit, improving youth awareness about sleep hygiene, targeting caffeine consumption and electronic use, and introducing sleep recommendations through appropriate and effective channels.

Sleep problems and mental health among young Norwegian adolescents

PURPOSE

The present study investigated the associations between the aspects of sleep problems and mental health in Norwegian young adolescents.

MATERIALS AND METHODS

Adolescents (12-13 years) were recruited from the primary schools in Telemark County, Norway. Sleep related problems were assessed by asking parents three questions related to their childrens' sleep quality, sleep sufficiency, and daytime sleepiness. Parents reported data on mental health by the extended version of the Strengths and Difficulties Questionnaire (SDQ), and information on the child's physical activity, screen time, eating pattern, gender, and background variables. Height and weight were objectively measured. Complete data were obtained for 690 adolescents.

RESULTS

Multiple logistic regressions were used. Bivariate analyses indicated important associations between the sleep aspects and mental health. When adjusting the sleep variables for each other, lifestyle factors and background variables, sleep quality problems were associated with any psychiatric problem (OR_adj: 4.0, CI: 2.0-8.2), emotional problems (OR_adj: 15.1, CI: 3.4-66.8), and hyperactivity-inattention problems (OR_adj: 5.1, CI: 2.2-12.1). Daytime sleepiness problems were associated with any psychiatric problem (OR_adj: 2.3, CI: 1.2-4.4), and hyperactivity-inattention problems (OR_adj: 2.5, CI: 1.1-5.5). Bivariate associations between problems with sufficient sleep and mental health problems lost the significance when adjusted for other sleep variables.

CONCLUSIONS

The results indicate that different aspects of sleep problems may be important underlying factors for mental health problems in adolescents, independently of lifestyle factors, BMI-category, gender, and background variables. This highlights the importance of examining specific sleep problems when investigating associations between sleep and mental health.

Review of Neurobiological Influences on Externalizing and Internalizing Pathways to Alcohol Use Disorder

Purpose of review

Two developmental courses through which alcohol use disorder (AUD) may emerge include externalizing and internalizing pathways. We review recent neuroimaging studies of potential neural risk factors for AUD and link findings to potential behavioral risk factors for AUD.

Recent findings

There is evidence that early-emerging weakness in prefrontal functioning and later-emerging differences in reward-system functioning contribute to an externalizing risk pathway. Stress may be an important contributor in the internalizing pathway through a blunting of reward-related activation, which may act alone or in combination with heightened emotion-related reactivity.

Summary

This review highlights areas for future work, including investigation of the relative balance between prefrontal and subcortical circuitry, attention to stages of AUD, and consideration of environmental factors such as stress and sleep. Particularly important is longitudinal work to understand the temporal ordering of associations among brain maturation, behavioral risk, and alcohol use.

Sleep and mindfulness meditation as they relate to false memory

By a systematic analysis of the current literature, we compare two states of sleep and meditation in terms of their role in the formation or suppression of Deese-Roediger-McDermott (DRM) false memory. We aim to suggest that the occurrence of false memory under these two states is a result of reinforcing some abilities and changes in cognitive systems which can ultimately improve some aspects of cognitive functions. In our analogy, we propose that: (1) both sleep and meditation may improve source monitoring ability whose failure is one of the most important mechanisms in producing false memories, and (2) despite improvement in source monitoring ability, adaptive cognitive processes, as mechanisms which are common in sleep and meditation, can still produce false memories. In conclusion, we propose that in spite of their contribution to false memory through adaptive processes, the beneficial role of sleep and meditation in cognition may be more prominent than their harmful role.

Developmental changes of sleep spindles and their impact on sleep-dependent memory consolidation and general cognitive abilities: A longitudinal approach

Sleep spindles are related to sleep‐dependent memory consolidation and general cognitive abilities. However, they undergo drastic maturational changes during adolescence. Here we used a longitudinal approach (across 7 years) to explore whether developmental changes in sleep spindle density can explain individual differences in sleep‐dependent memory consolidation and general cognitive abilities. Ambulatory polysomnography was recorded during four nights in 34 healthy subjects (24 female) with two nights (baseline and experimental) at initial recording (age range 8–11 years) and two nights at follow‐up recording (age range 14–18 years). For declarative learning, participants encoded word pairs with a subsequent recall before and after sleep. General cognitive abilities were measured by the Wechsler Intelligence Scale. Higher slow (11–13 Hz) than fast (13–15 Hz) spindle density at frontal, central, and parietal sites during initial recordings, followed by a shift to higher fast than slow spindle density at central and parietal sites during follow‐up recordings, suggest that mature spindle topography develops throughout adolescence. Fast spindle density increases from baseline to experimental night were positively related to sleep‐dependent memory consolidation. In addition, we found that the development of fast spindles predicted the improvement in memory consolidation across the two longitudinal measurements, a finding that underlines a crucial role for mature fast spindles for sleep‐dependent memory consolidation. Furthermore, slow spindle changes across adolescence were related to general cognitive abilities, a relationship that could indicate the maturation of frontal networks relevant for efficient cognitive processing. A video abstract of this article can be viewed at: https://www.youtube.com/watch?v=7NXJzm8HbIw and https://www.youtube.com/watch?v=iuMQY1OIJ0s

Mechanisms underlying the association between insomnia, anxiety, and depression in adolescence: Implications for behavioral sleep interventions

There is robust evidence of an association between insomnia, anxiety, and depression in adolescence. The aim of this review is to describe and synthesize potential mechanisms underlying this association and explore implications for the design of adolescent behavioral sleep interventions. Specifically, we examine whether insomnia symptoms are a mechanism for the development of internalizing symptoms in adolescence and whether sleep interventions are an effective treatment for both insomnia and internalizing symptoms in adolescence because they target the shared mechanisms underlying these disorders. Research using different methodologies points to the role of sequential, parallel, and interacting mechanisms. In this paper, we review a wide range of relevant biological (i.e., polymorphisms and dysregulation in serotonin, dopamine, and circadian clock genes; alterations in corticolimbic and mesolimbic brain circuits; cortisol reactivity to stress; inflammatory cytokine dysregulation; biased memory consolidation; changes in sleep architecture), psychological (i.e., cognitive inflexibility, interpretational biases, judgment biases, negative attribution styles, worry, rumination, biased attention to threat, dysfunctional beliefs and attitudes about sleep, misperception of sleep deficit), and social mechanisms (i.e., reduced and impaired social interactions, unhelpful parenting behaviors, family stress) and propose an integrative multilevel model of how these phenomena may interact to increase vulnerability to both insomnia and internalizing disorders. Several 'biopsychosocial' mechanisms hold promise as viable treatment targets for adolescent behavioral sleep interventions, which may reduce both insomnia and internalizing symptoms.

Heritability of Sleep EEG Topography in Adolescence: Results from a Longitudinal Twin Study

The topographic distribution of sleep EEG power is a reflection of brain structure and function. The goal of this study was to examine the degree to which genes contribute to sleep EEG topography during adolescence, a period of brain restructuring and maturation. We recorded high-density sleep EEG in monozygotic (MZ; n = 28) and dizygotic (DZ; n = 22) adolescent twins (mean age = 13.2 ± 1.1 years) at two time points 6 months apart. The topographic distribution of normalized sleep EEG power was examined for the frequency bands delta (1-4.6 Hz) to gamma 2 (34.2-44 Hz) during NREM and REM sleep. We found highest heritability values in the beta band for NREM and REM sleep (0.44 ≤ h2 ≤ 0.57), while environmental factors shared amongst twin siblings accounted for the variance in the delta to sigma bands (0.59 ≤ c2 ≤ 0.83). Given that both genetic and environmental factors are reflected in sleep EEG topography, our results suggest that topography may provide a rich metric by which to understand brain function. Furthermore, the frequency specific parsing of the influence of genetic from environmental factors on topography suggests functionally distinct networks and reveals the mechanisms that shape these networks.

The bidirectional association between sleep problems and autism spectrum disorder: a population-based cohort study

Background

Sleep difficulties are prevalent in children with autism spectrum disorder (ASD). The temporal nature of the association between sleep problems and ASD is unclear because longitudinal studies are lacking. Our aim is to clarify whether sleep problems precede and worsen autistic traits and ASD or occur as a consequence of the disorder.

Methods

Repeated sleep measures were available at 1.5, 3, 6, and 9 years of age in 5151 children participating in the Generation R Study, a large prospective birth cohort in the Netherlands. Autistic traits were determined with the Pervasive Developmental Problems score (PDP) of the Child Behavior Checklist (CBCL) at 1.5 and 3 years and the Social Responsiveness Scale (SRS) at 6 years. This cohort included 81 children diagnosed with ASD.

Results

Sleep problems in early childhood were prospectively associated with a higher SRS score, but not when correcting for baseline PDP score. By contrast, a higher SRS score and an ASD diagnosis were associated with more sleep problems at later ages, even when adjusting for baseline sleep problems. Likewise, a trajectory of increasing sleep problems was associated with ASD.

Conclusions

Sleep problems and ASD are not bidirectionally associated. Sleep problems do not precede and worsen autistic behavior but rather co-occur with autistic traits in early childhood. Over time, children with ASD have an increase in sleep problems, whereas typically developing children have a decrease in sleep problems. Our findings suggest that sleep problems are part of the construct ASD.

Restoring Serotonergic Homeostasis in the Lateral Hypothalamus Rescues Sleep Disturbances Induced by Early-Life Obesity

Early-life obesity predisposes to obesity in adulthood, a condition with broad medical implications including sleep disorders, which can exacerbate metabolic disturbances and disrupt cognitive and affective behaviors. In this study, we examined the long-term impact of transient peripubertal diet-induced obesity (ppDIO, induced between 4 and 10 weeks of age) on sleep-wake behavior in male mice. EEG and EMG recordings revealed that ppDIO increases sleep during the active phase but reduces resting-phase sleep quality. This impaired sleep phenotype persisted for up to 1 year, although animals were returned to a non-obesiogenic diet from postnatal week 11 onwards. To better understand the mechanisms responsible for the ppDIO-induced alterations in sleep, we focused on the lateral hypothalamus (LH). Mice exposed to ppDIO did not show altered mRNA expression levels of orexin and melanin-concentrating hormone, two peptides that are important for sleep-wake behavior and food intake. Conversely, the LH of ppDIO-exposed mice had reduced contents of serotonin (5-hydroxytryptamine, 5-HT), a neurotransmitter involved in both sleep-wake and satiety regulation. Interestingly, an acute peripheral injection of the satiety-signaling peptide YY 3-36 increased 5-HT turnover in the LH and ameliorated the ppDIO-induced sleep disturbances, suggesting the therapeutic potential of this peptide. These findings provide new insights into how sleep-wake behavior is programmed during early life and how peripheral and central signals are integrated to coordinate sleep.SIGNIFICANCE STATEMENT Adult physiology and behavior are strongly influenced by dynamic reorganization of the brain during puberty. The present work shows that obesity during puberty leads to persistently dysregulated patterns of sleep and wakefulness by blunting serotonergic signaling in the lateral hypothalamus. It also shows that pharmacological mimicry of satiety with peptide YY_3-36 can reverse this neurochemical imbalance and acutely restore sleep composition. These findings add insight into how innate behaviors such as feeding and sleep are integrated and suggest a novel mechanism through which diet-induced obesity during puberty imposes its long-lasting effects on sleep-wake behavior.

If You Build It, They Will Come: Initial Experience with a Multi-Disciplinary Pediatric Neurocritical Care Follow-Up Clinic

Pediatric Neurocritical Care diagnoses account for a large proportion of intensive care admissions. Critical care survivors suffer high rates of long-term morbidity, including physical disability, cognitive impairment, and psychosocial dysfunction. To address these morbidities in Pediatric Neurocritical Care survivors, collaboration between Pediatric Neurology and Pediatric Critical Care created a multidisciplinary follow-up clinic providing specialized evaluations after discharge. Clinic referrals apply to all Pediatric Neurocritical Care patients regardless of admission severity of illness. Here, we report an initial case series, which revealed a population that is heterogenous in age, ranging from 1 month to 18 years, and in diagnoses. Traumatic brain injuries of varying severity as well as neuroinfectious and inflammatory diseases accounted for the majority of referrals. Most patients (87%) seen in the clinic had morbidities identified, requiring ongoing evaluation and expansion of the clinic. Cognitive and psychological disturbance were seen in over half of patients at the initial clinic follow-up. Sleep disturbances, daytime fatigue, headache or chronic pain, and vision or hearing concerns were also common at initial follow-up. Data from this initial population of clinic patients reiterates the need for specialized follow-up care, but also highlights the difficulties related to providing this comprehensive care and evaluating interventions to improve outcomes.

The mediating role of cortical thickness and gray matter volume on sleep slow-wave activity during adolescence

During the course of adolescence, reductions occur in cortical thickness and gray matter (GM) volume, along with a 65% reduction in slow-wave (delta) activity during sleep (SWA) but empirical data linking these structural brain and functional sleep differences, is lacking. Here, we investigated specifically whether age-related differences in cortical thickness and GM volume and cortical thickness accounted for the typical age-related difference in slow-wave (delta) activity (SWA) during sleep. 132 healthy participants (age 12-21 years) from the National Consortium on Alcohol and NeuroDevelopment in Adolescence study were included in this cross-sectional analysis of baseline polysomnographic, electroencephalographic, and magnetic resonance imaging data. By applying mediation models, we identified a large, direct effect of age on SWA in adolescents, which explained 45% of the variance in ultra-SWA (0.3-1 Hz) and 52% of the variance in delta-SWA (1 to <4 Hz), where SWA was lower in older adolescents, as has been reported previously. In addition, we provide evidence that the structure of several, predominantly frontal, and parietal brain regions, partially mediated this direct age effect, models including measures of brain structure explained an additional 3-9% of the variance in ultra-SWA and 4-5% of the variance in delta-SWA, with no differences between sexes. Replacing age with pubertal status in models produced similar results. As reductions in GM volume and cortical thickness likely indicate synaptic pruning and myelination, these results suggest that diminished SWA in older, more mature adolescents may largely be driven by such processes within a number of frontal and parietal brain regions.

Sleep duration, quality of life and depression in adolescents: a school-based survey

BACKGROUND

The main objective of this study was to assess the link between sleep duration, quality of life and depression in adolescents. The secondary objective was to study the sleeping behavior of a large sample of adolescents from different socioeconomic backgrounds.

METHODS

Study subjects were high school students studying in or around Paris with a general, vocational or technological training background. A survey was conducted to evaluate the subject's perception of their own sleep, quality of life and depression.

RESULTS

The survey analyzed 855 students between 14 and 19 years of age, with equal numbers of males and females. The average sleep duration was 7 h 14 min ±1 h 20 min and was inversely correlated with age (r=-0.142, P<0.01). Students studying vocational subjects reported significantly more sleep than students studying technological subjects (P=0.02). Univariate analyses revealed a positive relationship between sleep duration and quality of life (r=0.17, P<0.001) and an inverse relationship between sleep duration and depression (r=-0.5, P<0.001). Multivariate analyses identified depression, delayed sleep phase disorder, and medical condition as determinants of sleep duration.

CONCLUSIONS

This investigation of a large student cohort has confirmed that the average sleep duration in adolescents is far below what is recommended. Depression significantly influenced sleep duration. We recommend that a quantitative and qualitative evaluation of sleep should be made during the medical examination of any adolescent.