A meta-analysis of longitudinal studies on the interplay between sleep, mental health, and positive well-being in adolescents / Un metaanálisis de estudios longitudinales sobre la interacción entre el sueño, la salud mental y el bienestar positivo en adolescentes

Objective: This review aimed to summarize longitudinal research about the interplay between sleep, mental health, and positive well-being in adolescents. Method: Multiple search strategies were applied until 28th January 2023 to identify relevant research published in peer-reviewed journal articles or available grey literature. A final set of 63 studies were included in the systematic review and 42 in the meta-analysis. Results: Results highlighted that long sleep duration, good sleep quality, and low insomnia symptoms were bidirectionally related to lower internalizing (Sleep T1 → Internalizing symptoms T2: r = -.20, p < .001; Internalizing symptoms T1 → Sleep T2: r = -.21, p < .001) and externalizing (Sleep T1 → Externalizing symptoms T2: r = -.15, p < .001; Externalizing symptoms T1→ Sleep T2: r = -.17, p < .001) symptoms, and to higher levels of psychological well-being (Sleep T1 → Psychological well-being T2: r = .15, p < .001; Psychological well-being T1 → Sleep T2: r = .15, p < .05). Moreover, good sleep was positively related to higher subjective well-being at a later time point (r = .18, p < .001). Conclusions: Overall, these findings suggest a bidirectional relation between different aspects of sleep, mental health, and positive well-being.(AU)

A meta-analysis of longitudinal studies on the interplay between sleep, mental health, and positive well-being in adolescents.

Objective: This review aimed to summarize longitudinal research about the interplay between sleep, mental health, and positive well-being in adolescents. Method: Multiple search strategies were applied until 28th January 2023 to identify relevant research published in peer-reviewed journal articles or available grey literature. A final set of 63 studies were included in the systematic review and 42 in the meta-analysis. Results: Results highlighted that long sleep duration, good sleep quality, and low insomnia symptoms were bidirectionally related to lower internalizing (Sleep T1 â†’ Internalizing symptoms T2: r = -.20, p < .001; Internalizing symptoms T1 â†’ Sleep T2: r = -.21, p < .001) and externalizing (Sleep T1 â†’ Externalizing symptoms T2: r = -.15, p < .001; Externalizing symptoms T1→ Sleep T2: r = -.17, p < .001) symptoms, and to higher levels of psychological well-being (Sleep T1 â†’ Psychological well-being T2: r = .15, p < .001; Psychological well-being T1 â†’ Sleep T2: r = .15, p < .05). Moreover, good sleep was positively related to higher subjective well-being at a later time point (r = .18, p < .001). Conclusions: Overall, these findings suggest a bidirectional relation between different aspects of sleep, mental health, and positive well-being.

The Longitudinal Interplay between Sleep, Anthropometric Indices, Eating Behaviors, and Nutritional Aspects: A Systematic Review and Meta-Analysis.

Sleep is fundamental for adolescents' healthy development but undergoes dramatic changes in quantity and quality due to the conflict between biological and social rhythms. Insufficient sleep has been associated with worse physical health status and irregular eating behaviors in adolescents. This review aims to systematically synthesize the longitudinal associations between adolescents' sleep dimensions (i.e., duration, timing, quality, and insomnia symptoms) and physical health indicators (i.e., anthropometric indices, fat percentage, and risk of obesity), eating behaviors, and nutritional aspects (i.e., type of diet related to the intake of specific foods and nutrients, amount and timing of food consumption, energy expenditure). A total of 28 longitudinal studies were included. The meta-analytic results showed that longer sleep duration, better sleep quality, and lower insomnia symptoms were associated with lower BMI and fat percentage and that shorter sleep duration (<7 h) and lower sleep quality were associated with a higher risk of obesity. Conversely, anthropometric indices were not related to sleep over time. Limited literature examined the bidirectional association between adolescents' sleep and their eating behaviors and nutritional aspects. Such knowledge sheds new light on the role of sleep for adolescents' health, highlighting the need to examine further the interplay between these variables.

Non-pharmacological and melatonin interventions for pediatric sleep initiation and maintenance problems: A systematic review and network meta-analysis.

Sleep initiation and maintenance problems are common in the pediatric population and while behavioral interventions are recommended, their efficacy remains to be evaluated in clinical trials. We conducted a systematic review and network meta-analysis to assess the efficacy of non-pharmacological treatments and melatonin for sleep initiation and maintenance problems in healthy pediatric populations. We included 30 studies in the systematic review and 15 in the meta-analysis. Three network meta-analyses were conducted for sleep onset latency (SOL), wake after sleep onset (WASO), and total sleep time (TST). For SOL variable, the results support greater effectiveness of light therapy and melatonin than evidence-based psychological interventions, whether implemented in combination with light therapy or not. Regarding WASO variable, evidence-based psychological interventions and a combination of those techniques plus light treatment were the most efficacious. Finally, for TST variable, a larger effect was shown for the combined treatment of evidence-based psychological intervention with light therapy in comparison to other interventions. In conclusion, we found a high variability between study protocols likely impacting the results of the meta-analysis. Future randomized control trials studies, stratified by pediatric age classes, are needed in order to provide clear suggestions in clinical settings.

A systematic review and meta-analysis of the association between young adults' sleep habits and substance use, with a focus on self-medication behaviours.

Young adults (18-30 years) are vulnerable to sleep-wake disturbances and substance use, which are bi-directionally associated. The present work aims to organise the literature that deals with the association between sleep and substance use in young adults, also considering self-medication behaviours. We adopted a framework that accounts for the multidimensionality of sleep and the effect of different substances. We considered sleep disturbances (insomnia symptoms, sleep quality), sleep health dimensions (duration, satisfaction, efficiency, timing, daytime alertness), circadian characteristics (chronotype). Substances were alcohol, caffeine, nicotine, cannabis, others. We included 46 studies. The use of caffeine and nicotine was associated with higher odds of sleep disturbances. No significant effect was detected for sleep duration. In narrative findings, daytime dysfunction was associated with alcohol and caffeine use, and poor sleep satisfaction with nicotine use. Few evidence were available for the other sleep health dimensions. Evening chronotype was associated with alcohol, caffeine, and nicotine use. Few studies focused on cannabis or self-medication. Longitudinal results were inconclusive. We found a distinct pattern of associations between different substances and different sleep outcomes. Further investigation considering the multidimensionality of sleep would create a better understanding of the complex relationship between substance use and sleep health in young adults.

Differential Associations of Cognitive Emotion Regulation Strategies with Depression, Anxiety, and Insomnia in Adolescence and Early Adulthood.

While difficulties with emotion regulation (ER) are consistently linked to poor mental health in adulthood, findings in adolescence have been more mixed. Cognitive ER strategies, which involve the ability to manage emotions through mental processes, may be particularly important during different stages of development due to age-specific adjustments. We conducted two exploratory and cross-sectional studies to examine the relationships between cognitive ER strategies and mental health (i.e., depressive, anxiety, and insomnia symptoms) in two samples: 431 young adults (Mage = 20.66 ± 2.21; 70% women and 30% men) and 271 adolescents (Mage = 14.80 ± 0.0.59; 44.6% girls and 55.4% boys). The participants completed a group of questionnaires, including the Cognitive Emotion Regulation Questionnaire, the Insomnia Severity Index, the Beck Depression Inventory-II, the State-Trait Anxiety Inventory, and the Youth Self Report. We employed hierarchical multiple regressions to assess the unique contribution of cognitive ER strategies to mental health outcomes. Maladaptive strategies (such as rumination and catastrophizing) were consistently associated with impaired mental health in both samples, while adaptive strategies (such as positive refocusing and positive reappraisal) were only associated with better mental health in young adults. These findings support the importance of cognitive ER strategies as potential risk factors for psychopathology and suggest that interventions aimed at improving emotion regulation may be beneficial. The age-specific differences in the relationship between cognitive ER strategies and mental health may reflect the refinement of emotion regulation abilities across the lifespan.

External validity of the reduced Morningness-Eveningness Questionnaire for Children and Adolescents: an actigraphic study.

The aim of this study was to examine the external validity of the reduced Morningness-Eveningness Questionnaires for Children and Adolescents, using circadian motor activity, assessed through actigraphy, as an external criterion. Overall, 458 participants (269 females), with a mean (standard deviation) age of 15.75 (1.16) years, took part in this study. Each adolescent was requested to wear the actigraph Micro Motionlogger Watch actigraph (Ambulatory Monitoring, Inc., Ardlsey, NY, USA) around the non-dominant wrist for 1 week. At the end of the actigraphic recording, participants completed the reduced Morningness-Eveningness Questionnaires for Children and Adolescents. We extracted the motor activity counts, minute-by-minute over the 24 h, to depict the 24-h motor activity pattern, and we adopted the statistical framework of functional linear modelling to examine its changes according to chronotype. According to the reduced Morningness-Eveningness Questionnaires for Children and Adolescents cut-off scores, 13.97% of participants (n = 64) belonged to the evening-types category, 9.39% (n = 43) to morning-types, while the remaining (76.64%, n = 351) to the intermediate-types category. Evening types moved significantly more than the intermediate and morning types from around 10:00 p.m. to 2:00 a.m., while the opposite pattern of results was observed around 4:00 a.m. The results highlighted a significant difference in the 24-h motor activity pattern between chronotypes, in line with the expectations based on their well-known behaviour. Therefore, this study shows that the external validity of the reduced Morningness-Eveningness Questionnaire for Children and Adolescents, established by considering motor activity (recorded through actigraphy) as an external criterion, is satisfactory.

Sleep Is a Family Affair: A Systematic Review and Meta-Analysis of Longitudinal Studies on the Interplay between Adolescents' Sleep and Family Factors.

Family is one of the primary socialization contexts influencing adolescents' psychological health. In this regard, a crucial indicator of adolescents' health is their sleep quality. Nevertheless, it is still unclear how multiple family factors (i.e., demographic and relational) are intertwined with adolescents' sleep quality. For this reason, this systematic review with meta-analysis aims to comprehensively summarize and integrate previous longitudinal research investigating the reciprocal relation between demographics (e.g., family structure) and positive (e.g., family support) and negative (e.g., family chaos) relational family factors and adolescents' sleep quality. Several search strategies were applied, and a final set of 23 longitudinal studies that matched the eligibility criteria were included in this review. The total number of participants was 38,010, with an average age at baseline of 14.7 years (SD = 1.6, range: 11-18 years). On the one hand, the meta-analytic results showed that demographic factors (e.g., low socio-economic status) were not related to adolescents' sleep quality at a later time point. On the other hand, positive and negative family relational factors were positively and negatively related to adolescents' sleep, respectively. Furthermore, the results suggested that this association could be bidirectional. Practical implications and suggestions for future research are discussed.

Sleep Well, Study Well: A Systematic Review of Longitudinal Studies on the Interplay between Sleep and School Experience in Adolescence.

Adolescents spend most of their daily time in school and performing school-related activities. Different aspects of their school experiences, such as school performance, psychological factors related to school, and structural factors, consistently impact adolescents' health and are likely to be intertwined with their sleep (i.e., quantity and quality, sleep disturbances). This systematic review aimed to comprehensively summarize the reciprocal and longitudinal associations between adolescents' sleep and multiple aspects of their school experience. Using multiple search strategies and applying a two-step selection process, 25 journal articles matched the eligibility criteria and were thus included in the review. The results highlighted the contribution of poor sleep quality and sleep disturbances in predicting longitudinal school experiences-related outcomes (i.e., decreasing school engagement and performance, and increasing school-related burnout, absenteeism, and bullying). At the same time, the results showed how experiences related to the school's psychological factors (e.g., high levels of school burnout and stressful environment) and structural characteristics (e.g., early school entrance time) affect youth sleep over time (i.e., decreasing sleep quality and quantity). These main findings provided novel insights into the bidirectional relationship between school experience and sleep health, highlighting the importance of more longitudinal research investigating all aspects of healthy sleep, including the size and direction of the association.

The Association between Sleep Patterns, Educational Identity, and School Performance in Adolescents.

Adolescents' school experience can be developmentally related to adolescents' sleep. This study aimed to understand how sleep patterns (i.e., sleep duration and sleep-schedule) and weekend sleep-recovery strategies (i.e., social jetlag and weekend catch-up sleep) are associated with adolescents' school experience (i.e., educational identity and school performance). Moreover, the differences in the school experiences between adolescents with different numbers of weekend-sleep-recovery strategies were assessed. For this purpose, 542 Italian adolescents (55.2% females, mean age 15.6 years) wore an actigraph for one week. After the actigraphic assessment, questionnaires on educational identity and school performance were administered. Results showed that short sleep-duration, later bedtime during weekdays and weekends, and a higher amount of social jetlag were negatively associated with school performance. Furthermore, adolescents who did not use any sleep-recovery strategy during the weekend presented lower levels of educational in-depth exploration compared to adolescents with higher levels of catch-up sleep but not social jetlag. These data pointed out a potentially detrimental role of social jetlag on school performance and differences in identity processes between adolescents who used and those who did not use sleep-recovery strategies, which could affect adolescents' psychosocial adjustment.

The Social Side of Sleep: A Systematic Review of the Longitudinal Associations between Peer Relationships and Sleep Quality.

In adolescence, peer relationships become crucial since youths start to rely on their peers for support. Thus, multiple facets of adolescents' well-being are affected by their peer relationships. In this vein, one of the central well-being aspects that could be affected by the peer relationships of adolescents is sleep quality. Nevertheless, it is still unclear how multiple peer relationship factors (i.e., positive, negative, emotional, and behavioral issues related to peer relationships) are intertwined with adolescents' sleep quality. For this reason, this systematic review with meta-analysis aims to summarize longitudinal studies to uncover how the interplay between peer relationship factors and adolescents' sleep quality unfolds over time. Nineteen longitudinal studies involving a total of 21,232 adolescents were included. Overall, findings from this review showed that (a) positive peer relationships and sleep quality were not associated over time; (b) negative peer relationships and sleep quality were bidirectionally associated over time; (c) few studies evaluated the bidirectional relations between emotional and behavioral issues and sleep quality, showing links with sleep schedule and duration, but not with sleep quality. Meta-analytic results were discussed, considering their implications.

The impact of COVID-19 on Italian adolescents' sleep and its association with psychological factors.

Insomnia and circadian dysregulation during adolescence represent important risk factors for emotional and psychological problems. Recent studies have shown that the coronavirus disease 2019 (COVID-19) pandemic has been linked to a high prevalence of behavioural sleep problems in the general population. This study aimed to provide two pictures of two different time points of the pandemic regarding the prevalence of sleep problems in adolescents and their association with psychological health variables. Two different independent large samples of Italian adolescents aged 13-17 years were recruited at two pandemic time points. A total of 1,146 adolescents at Time 1 (T1; April 2020) and 1,406 at Time 2 (T2; April 2021) took part in the study. Measures of insomnia symptoms, sleep hygiene, chronotype, psychological distress and emotion regulation were collected. Prevalence of insomnia was 12.13% at T1 and 23.19% at T2. Furthermore, high levels of poor sleep habits (late bedtime, poor sleep hygiene, use of electronic devices at bedtime) were also detected at both time points. Insomnia symptoms strongly correlated with poor sleep hygiene, higher psychological distress, and emotional suppression at both time points. Results highlighted an alarming picture for two large samples at two different time points of the pandemic that showed a potential negative impact of the COVID-19 pandemic, in both the first outbreak and in the later phase of the pandemic, on sleep habits, psychological distress and insomnia symptoms in adolescents. This strongly suggests the need for monitoring these variables and their interaction in the post-pandemic period and to develop and promote interventions for insomnia and circadian disturbances during adolescence.

Psychological correlates of insomnia in professional soccer players: An exploratory study.

Sleep promotes health, well-being, recovery and athletic performance. As a consequence, sleep problems in athletes may have detrimental effects. Previous investigations showed that professional athletes often reported to suffer of poor sleep quality and insomnia (e.g. difficulties falling asleep and/or maintaining sleep). However, psychological variables exacerbating and maintaining insomnia in professional athletes as well as its mechanistic pathways are still largely unknown. Available literature mostly focused on effects of sport-related variables, such as evening training and stimulant consumption on athletes' sleep. Instead, the contribution of cognitive and emotional variables globally associated with insomnia in athletes in clinical models has been largely neglected. To address these limitations, this study explored the associations between emotional experience, pre-sleep arousal, pre-sleep worry and rumination and insomnia severity in a sample of 210 (25.93 ± 6.68 years) male professional soccer players. Bivariate correlations, multiple regression, and structural equation modelling with manifest variables (path analysis) were computed. Results showed that insomnia severity was associated with stimulants consumption, pre-sleep arousal, negative emotions, positive emotions, and pre-sleep worry/rumination (all p < .05). Path analysis showed that relationship between stimulant consumption, emotional experience, worry/rumination and insomnia was mediated by pre-sleep arousal (p < .05). Our results suggest that preventive and interventional studies in professional soccer players would benefit from considering global cognitive-emotional variables as targets of interventions.HighlightsInsomnia was associated with greater stimulants consumption, pre-sleep arousal, negative emotions, pre-sleep worry/rumination, and lower positive emotions.Path analysis showed that pre-sleep arousal mediated the relationship between stimulant consumption, emotional experience, worry/rumination and insomnia severity.Cognitive-emotional and behavioural factors as well as sport-related variables were important predictors of insomnia in professional soccer players.

Validation study of the Italian version of the Sleep Hygiene Index.

Sleep hygiene rules are a set of behavioural and environmental recommendations that promote healthy and good quality sleep, playing a role in insomnia disorder. The Sleep Hygiene Index (SHI) is a self-report questionnaire developed to evaluate the practice of sleep hygiene behaviours with adequate psychometric properties in different samples. The present study aimed to translate the original version of the SHI into the Italian language and evaluate the psychometric properties of this instrument in the Italian adult population. After the translation of the SHI from the original English version into the Italian version, factorial structure, internal consistency, as well as convergent and discriminant validity were estimated. The principal component analysis showed a four-factor solution for the SHI, accounting for 52.03% of the total sample variance (F1 = 25.65%, F2 = 10.00%, F3 = 8.48% and F4 = 7.90%). Factor 1 comprised items regarding arousal; Factor 2 comprised items regarding regular sleep habits; Factor 3 comprised items about sleep environment; and Factor 4 comprised items on sleep-disrupted behaviours. The Italian version of the SHI can be regarded as a reliable tool with adequate concurrent and predictive validity for assessing sleep hygiene in Italian adults with or without insomnia symptoms.

Different Effects of Social Jetlag and Weekend Catch-Up Sleep on Well-Being of Adolescents According to the Actual Sleep Duration.

The aim of this study was to explore the potentially different associations between two common aspects of adolescents' life, namely social jetlag and weekend catch-up sleep, with well-being and physical health, according to the actual sleep duration, i.e., <7 h and ≥7 h. To this end, 504 participants (42.1% males), with a mean age of 16.17 (standard deviation = 1.39), were examined in the this cross-sectional study. Participants were asked to wear the Micro Motionlogger Watch actigraph (Ambulatory Monitoring, Inc., Ardlsey, NY, USA) around their non-dominant wrist for seven consecutive days in order to objectively assess social jetlag and weekend catch-up sleep. Participants were also asked to fill in the Mental Health Continuum­Short Form for the assessment of subjective, social, and psychological well-being, as well as the SF-36 Health Survey for the perception of physical health. In adolescents sleeping less than 7 h, those experiencing weekend catch-up sleep longer than 120 min reported significantly lower subjective well-being compared to those with a weekend catch-up sleep duration between 0 and 59 min. These data pointed out the detrimental effect of long weekend catch-up sleep on self-reported well-being only in adolescents getting less than the recommended amount of sleep.

Sleep Characteristics in Italian Children During Home Confinement Due to Covid-19 Outbreak.

OBJECTIVE: Italy faced one of the first large clusters of COVID-19 infections worldwide. Home confinement and social distancing could have negatively impacted sleep habits and prevalence of sleep disorders in children, which may be also linked with altered emotional processes. The present study focused on clinical aspects related to sleep, insomnia and emotions in Italian children aged 0-to-12 years during home confinement due to COVID-19 outbreak. METHOD: An online survey was systematically distributed in all Italian territories by contacting regional offices of the Italian Ministry of Instruction, University and Research (MIUR) and schools with available contact. All respondents had to be parents of at least one child aged 0 to 12 years old. Information on sociodemographic variables, sleep habits, sleep health behaviors, sleep disorders and mood were collected. RESULTS: Parents of 2361 children (mean age: 8.1 ± 2.62 years; 1148 females; 1213 males) answered the survey. 1.2% of children was between 0 and 2 years old; 15.3% within 3 to 5 years and 83.3% within 6 and 12 years. In all group ages, late bedtime was observed (most of them after 9 p.m.). 59.4% of all children presented at least one clinical diagnostic criterion for childhood insomnia. Logistic regression model showed that presence of at least one criterion for childhood insomnia was associated to younger age, negative mood, current parental insomnia, being the only child, presence of any other sleep disorder, and sleep hygiene behaviors. CONCLUSIONS: Data indicate an alarming increase of prevalence of insomnia related problems in Italian children during home confinement with respect to previous data. This was found to be associated with poor sleep hygiene and negative mood. Clinical programs targeting insomnia, sleep health behaviors and emotional processes should be implemented in pediatric primary care in order to prevent the development of sleep problems in a post-pandemic situation.

Sleep Characteristics in the Italian Pediatric Population: A Systematic Review.

OBJECTIVE: During childhood sleep duration, quality and patterns evolve and change greatly and relate strongly to healthy development. This systematic review aims to summarize the literature on sleep characteristics in the Italian pediatric population, adopting a cultural perspective. METHOD: Pubmed, PsycINFO and Medline databases were systematically searched. Eligible studies had to: include Italian children and adolescents; report data for one or more sleep-related variables; be published in English or Italian. RESULTS: Twenty-nine studies were selected including 18551 Italian children or adolescents. Studies were categorized by age group: infancy and toddlerhood (0-3 years); preschool and school age (3-12 years); adolescence (12-18 years) and mixed age groups. Overall, studies showed that the Italian pediatric population present shorter sleep duration and longer sleep onset latency compared to international recommendations. Furthermore, data indicate high prevalence of dysfunctional sleep habits, such as late bed-time (all age groups), involvement of parents during bed-time (infancy and toddlerhood), and high variability between sleep times on week-days vs. weekends (adolescence). Nevertheless, most studies lacked comprehensive data on sleep patterns, focusing instead on isolated variables. CONCLUSION: These results suggest a strong trend among Italian children and adolescents towards unhealthy sleep patterns. Comprehensive data are still lacking and large studies evaluating a broad range of sleep characteristics in Italian pediatric populations are needed. Data strongly suggest that Italian Pediatric Primary Care should place higher focus on sleep problems and implement clinical protocols directed towards improving sleep patterns in children and adolescents.

Does cognitive behaviour therapy for insomnia reduce repetitive negative thinking and sleep-related worry beliefs? A systematic review and meta-analysis.

Repetitive negative thinking (RNT), i.e., worry, rumination, and transdiagnostic repetitive thinking, is thought to exacerbate and perpetuate insomnia in cognitive models. Moreover, RNT is a longitudinal precursor of depression and anxiety, which are often co-present alongside insomnia. Whilst accumulating evidence supports the efficacy of cognitive behavioural therapy for insomnia (CBT-I) in reducing depression and anxiety symptoms, the literature on the effects of CBT-I on RNT has never been systematically appraised. Importantly, preliminary evidence suggests that reduction of RNT following CBT-I may be associated with reduction of depression and anxiety. Therefore, we aimed to conduct a systematic review and meta-analysis on the effects of CBT-I on RNT. Seven databases were searched, and 15 randomised controlled trials were included. Results showed moderate-to-large effects of CBT-I on worry (Hedge's g range: -0.41 to g = -0.71) but small and non-reliable effects on rumination (g = -0.13). No clear evidence was found for an association between post-treatment reduction in RNT and post-treatment reduction in depression and anxiety. Although the literature is small and still developing, CBT-I seems to have a stronger impact on sleep-related versus general measures of RNT. We discuss a research agenda aimed at advancing the study of RNT in CBT-I trials.

The Association between Diurnal Sleep Patterns and Emotions in Infants and Toddlers Attending Nursery.

BACKGROUND: Childcare programs often include mandatory naptime during the day. Loss of daytime sleep could lead to a moderate-to-large decrease in self-regulation, emotion processing, and learning in early childhood. Nevertheless, daytime sleep has been less accurately studied than nighttime sleep. This study aims to explore the relationship between diurnal sleep habits in nursery settings, nocturnal sleep quality, and post-nap emotional intensity in infants and toddlers. METHODS: Data of 92 children (52 girls, 40 boys) aged 6 to 36 months were obtained. Sleep habits as well as positive and negative emotions were monitored by educators during nursery times through a sleep and emotion diary for two weeks. RESULTS: Explorative analyses showed that diurnal sleep hours decreased across age groups (except for females aged 25-36 months) and that all age groups had a lower amount of nocturnal sleep than is recommended by the National Sleep Foundation. Partial correlation analysis showed significant correlation between daytime sleep onset latency and positive emotions. Mediation analyses showed that daytime napping is relevant for emotional functioning independently of nocturnal sleep quality. CONCLUSIONS: Daytime sleep in early childhood seems to be linked to the management of positive and negative emotions and could play a role in healthy development of emotional processes.

The efficacy of cognitive and behavior therapies for insomnia on daytime symptoms: A systematic review and network meta-analysis.

Insomnia disorder, defined by nocturnal and daytime symptoms, is highly prevalent worldwide and is associated with the onset of mental illness. Although daytime symptoms are often the reason insomnia patients seek help, it is not clear whether recommended treatment is effective on daytime symptoms. We aimed to investigate the efficacy of cognitive and behavior therapies for insomnia (CBT-I) on all daytime symptoms explored in the literature using both direct and indirect data. 86 studies (15,578 participants) met inclusion criteria. Results showed significant effects of CBT-I administered face-to-face individually, in group and different self-help settings on depressive symptoms, anxiety, daytime sleepiness, fatigue, quality of life, daytime and social functioning and mental state, with Cohen's d's ranging from -0.52 and 0.81. Our results suggest that CBT-I is effective in the treatment of daytime symptoms, albeit with predominantly small to moderate effects compared to far stronger effects on the core symptoms of insomnia. Effects may be biased for depressive and anxiety symptoms, since many included studies excluded patients with severe levels of these complaints. Further, small to moderate effects may reflect that CBT-I, by improving nighttime symptoms, has a positive effect on daytime symptoms, but it does not target the daytime symptoms directly. Future studies may benefit from adding therapeutic techniques that address daytime symptoms more directly.