Childhood Schizotypy and Adolescent Mental Disorder.

BACKGROUND AND HYPOTHESIS: Schizotypy provides a framework for understanding the developmental nature of psychotic disorders and a means of identifying "at-risk" individuals early in the lifespan. However, there is a lack of prospective longitudinal research examining the relationship between schizotypy in childhood and later psychotic and other mental disorders. We hypothesized that distinct profiles of schizotypy in childhood would be differentially associated with psychotic and other mental disorders emerging later in adolescence. STUDY DESIGN: In a large population cohort of Australian young people (n = 26 837), we prospectively examined the relationship between person-centered profiles of schizotypy identified in middle childhood (age ~11 years) and adolescent diagnoses (age ~13-18 years) across 7 types of mental disorders using multinomial logistic regression. RESULTS: Membership in any of 3 childhood schizotypy profiles (true schizotypy, affective schizotypy, or introverted schizotypy) was associated with an increased likelihood of being diagnosed with any type of mental disorder in adolescence; effects were strongest for the true schizotypy group (aOR = 3.07, 95% CI = 2.64, 3.57), followed by the introverted (aOR = 1.94, 95% CI = 1.75, 2.15) and affective (aOR = 1.29, 95% CI = 1.13, 1.47) schizotypy groups. Six of the 7 types of mental disorders measured (including psychotic disorders) were associated with at least 1 schizotypy group. CONCLUSIONS: Schizotypy in middle childhood is an important correlate of mental disorders in adolescence; however, it does not appear to be specifically associated with psychotic disorders in this age group.

Early life exposure to air pollution and psychotic-like experiences, emotional symptoms, and conduct problems in middle childhood.

BACKGROUND: Air pollution has been linked to a variety of childhood mental health problems, but results are inconsistent across studies and the effect of exposure timing is unclear. We examined the associations between air pollution exposure at two time-points in early development and psychotic-like experiences (PLEs), and emotional and conduct symptoms, assessed in middle childhood (mean age 11.5 years). METHODS: Participants were 19,932 children selected from the NSW Child Development Study (NSW-CDS) with available linked multi-agency data from birth, and self-reported psychotic-like experiences (PLEs) and psychopathology at age 11-12 years (middle childhood). We used binomial logistic regression to examine associations between exposure to nitrogen dioxide (NO2) and particulate matter less than 2.5 µm (PM2.5) at two time-points (birth and middle childhood) and middle childhood PLEs, and emotional and conduct symptoms, with consideration of socioeconomic status and other potential confounding factors in adjusted models. RESULTS: In fully adjusted models, NO2 exposure in middle childhood was associated with concurrent PLEs (OR = 1.10, 95% CI = 1.02-1.20). Similar associations with PLEs were found for middle childhood exposure to PM2.5 (OR = 1.05, 95% CI = 1.01-1.09). Neither NO2 nor PM2.5 exposure was associated with emotional symptoms or conduct problems in this study. CONCLUSIONS: This study highlights the need for a better understanding of potential mechanisms of action of NO2 in the brain during childhood.

Measurement invariance of brief forms of the Schizotypal Personality Questionnaire across convenience versus random samples.

Schizotypy, a multifaceted personality construct that represents liability for schizophrenia, is generally measured with self-report questionnaires that have been developed and validated in samples of undergraduate students. Given that understanding schizotypy in non-clinical samples is essential for furthering our understanding of schizophrenia-spectrum psychopathologies, it is critical to test whether non-clinically identified undergraduate and other convenience samples respond to schizotypy scales in the same way as random samples of the general population. Here, 651 undergraduates, 350 MTurk workers, and two randomly selected high school samples (n = 177, n = 551) completed brief versions of the Schizotypal Personality Questionnaire (SPQ-BR or SPQ-BRU). Multigroup confirmatory factor analysis was used to test whether measurement invariance was present across samples. Tests were made for all samples together and for each pair of samples. Results showed that a first-order nine-factor model fit the data well, and this factor structure displayed configural and metric invariance across the four samples. This suggests that schizotypy has the same factor structure, and the SPQ-BR/BRU is measuring the same construct across the different groups. However, when all groups were compared, results indicated a lack of scalar invariance across these samples, suggesting mean comparisons may be inappropriate across different sample types. However, when randomly selected high school students were compared with undergraduate students, scalar invariance was present. This suggests that factors such as culture and form type may be driving invariance, rather than sampling method (convenience vs general population).

Cumulative comorbidity between neurodevelopmental, internalising, and externalising disorders in childhood: a network approach.

Cumulative comorbidity of mental disorders is common, but the extent and patterns of comorbid psychopathology in childhood are not well established. The current study aimed to elucidate the emergent patterns of cumulative mental disorder comorbidity in children using network analysis of diagnoses recorded between birth and age 12 years. Participants were 90,269 children (mean age 12.7 years; 51.8% male) within the New South Wales Child Development Study (NSW-CDS)-a longitudinal record-linkage cohort study of Australian children born in NSW between 2002 and 2005. Binary indicators for eight types of mental disorder were derived from administrative health records. Patterns of conditional association between mental disorders were assessed utilising network analysis. Of 90,269 children, 2268 (2.5%) had at least one mental disorder by age 12 years; of the 2268 children who had at least one mental disorder by age 12 years, 461 (20.3%) were diagnosed with two or more different disorders out of the eight disorder types included in analyses. All disorders were either directly or indirectly interconnected, with childhood affective and emotional disorders and developmental disorders being most central to the network overall. Mental disorder nodes aggregated weakly (modularity = 0.185) into two communities, representative of internalising and externalising disorders, and neurodevelopmental and sleep disorders. Considerable sex differences in the structure of the mental disorder comorbidity networks were also observed. Developmental and childhood affective and emotional disorders appear to be key to mental disorder comorbidity in childhood, potentially reflecting that these disorders share symptoms in common with many other disorders.

Self-harm and suicidal ideation among young people is more often recorded by child protection than health services in an Australian population cohort.

OBJECTIVE: We investigated patterns of service contact for self-harm and suicidal ideation recorded by a range of human service agencies - including health, police and child protection - with specific focus on overlap and sequences of contacts, age of first contact and demographic and intergenerational characteristics associated with different service responses to self-harm. METHODS: Participants were 91,597 adolescents for whom multi-agency linked data were available in a longitudinal study of a population cohort in New South Wales, Australia. Self-harm and suicide-related incidents from birth to 18 years of age were derived from emergency department, inpatient hospital admission, mental health ambulatory, child protection and police administrative records. Descriptive statistics and binomial logistic regression were used to examine patterns of service contacts. RESULTS: Child protection services recorded the largest proportion of youth with reported self-harm and suicidal ideation, in which the age of first contact for self-harm was younger relative to other incidents of self-harm recorded by other agencies. Nearly 40% of youth with a health service contact for self-harm also had contact with child protection and/or police services for self-harm. Girls were more likely to access health services for self-harm than boys, but not child protection or police services. CONCLUSION: Suicide prevention is not solely the responsibility of health services; police and child protection services also respond to a significant proportion of self-harm and suicide-related incidents. High rates of overlap among different services responding to self-harm suggest the need for cross-agency strategies to prevent suicide in young people.

Out-of-home care characteristics associated with childhood educational underachievement, mental disorder, and police contacts in an Australian population sample.

BACKGROUND: Children in out-of-home care (OOHC) are generally at increased risk of health and social adversities compared to their peers. However, the experiences of children in OOHC are not uniform and their associated health and social indices may vary in relation to characteristics of OOHC placements and child protection contact. OBJECTIVE: To examine associations between a range of characteristics of OOHC placements and child protection contact (e.g., number, type, and age of placement) with educational underachievement, mental disorder, and police contact (as a victim, witness, or person of interest) in childhood. PARTICIPANTS AND SETTING: Participants were Australian children drawn from the New South Wales Child Development Study cohort who had been placed in OOHC at least once between the ages of 0-13 years (n = 2082). METHODS: Logistic regression was used to examine prospective associations of OOHC placement and child protection contact characteristics (type of carer, placement instability, duration and frequency of maltreatment, and amount of time in care) with educational underachievement, mental disorder diagnosis and any type of police contact. RESULTS: Placements with foster carers, greater placement instability, longer and more frequent exposure to maltreatment, and longer time spent in care were each associated with greater likelihood of consequences in all domains of functioning. CONCLUSIONS: Children with certain placement characteristics are at higher risk of adverse consequences and should be prioritised for support services. The magnitude of relationships was not uniform across different health and social indices, highlighting the need for holistic, multiagency approaches to support children placed in care.

Parental mental disorders and offspring schizotypy in middle childhood: an intergenerational record linkage study.

PURPOSE: To investigate relationships between distinct schizotypy risk profiles in childhood and the full spectrum of parental mental disorders. METHODS: Participants were 22,137 children drawn from the New South Wales Child Development Study, for whom profiles of risk for schizophrenia-spectrum disorders in middle childhood (age ~ 11 years) were derived in a previous study. A series of multinomial logistic regression analyses examined the likelihood of child membership in one of three schizotypy profiles (true schizotypy, introverted schizotypy, and affective schizotypy) relative to the children showing no risk, according to maternal and paternal diagnoses of seven types of mental disorders. RESULTS: All types of parental mental disorders were associated with membership in all childhood schizotypy profiles. Children in the true schizotypy group were more than twice as likely as children in the no risk group to have a parent with any type of mental disorder (unadjusted odds ratio [OR] = 2.27, 95% confidence intervals [CI] = 2.01-2.56); those in the affective (OR = 1.54, 95% CI = 1.42-1.67) and introverted schizotypy profiles (OR = 1.39, 95% CI = 1.29-1.51) were also more likely to have been exposed to any parental mental disorder, relative to children showing no risk. CONCLUSION: Childhood schizotypy risk profiles appear not to be related specifically to familial liability for schizophrenia-spectrum disorders; this is consistent with a model where liability for psychopathology is largely general rather than specific to particular diagnostic categories.

Cumulative Environmental Risk in Early Life: Associations With Schizotypy in Childhood.

BACKGROUND AND HYPOTHESIS: Psychotic disorders are associated with a growing number of recognized environmental exposures. Cumulative exposure to multiple environmental risk factors in childhood may contribute to the development of different patterns of schizotypy evident in early life. Hypotheses were that distinct profiles of schizotypy would have differential associations with a cumulative score of environmental risk factors. STUDY DESIGN: We prospectively examined the relationship between 19 environmental exposures (which had demonstrated replicated associations with psychosis) measured from the prenatal period through to age 11 years, and 3 profiles of schizotypy in children (mean age = 11.9 years, n = 20 599) that have been established in population data from the New South Wales-Child Development Study. Multinomial logistic regression was used to examine associations between membership in each of 3 schizotypy profiles (true schizotypy, introverted schizotypy, and affective schizotypy) and exposure to a range of 19 environmental risk factors for psychosis (both individually and summed as a cumulative environmental risk score [ERS]), relative to children showing no risk. RESULTS: Almost all environmental factors were associated with at least 1 schizotypy profile. The cumulative ERS was most strongly associated with the true schizotypy profile (OR = 1.61, 95% CI = 1.52-1.70), followed by the affective (OR = 1.33, 95% CI = 1.28-1.38), and introverted (OR = 1.32, 95% CI = 1.28-1.37) schizotypy profiles. CONCLUSIONS: Consistent with the cumulative risk hypothesis, results indicate that an increased number of risk exposures is associated with an increased likelihood of membership in the 3 schizotypy profiles identified in middle childhood, relative to children with no schizotypy profile.

Strengthening associations between psychotic like experiences and suicidal ideation and behavior across middle childhood and early adolescence.

BACKGROUND: Understanding risk factors related to suicidal ideation (SI) and suicidal behaviors (SB) in youth is important for informing prevention and intervention efforts. While it appears that psychotic-like experiences (PLEs) are strongly associated with both SI and SB at different points across the lifespan, the longitudinal nature of this relationship in middle childhood and early adolescence is understudied. METHODS: The study used the unique longitudinal Adolescent Brain Cognitive Development Study data. Mixed effects linear models examined associations between PLEs and SI and SB over time using three time points of data from ages 9-13. RESULTS: First, analyses indicated that endorsement of SI and SB increased as youth grew older for those with increased distressing PLEs. Analyses found evidence of bidirectional relationships between PLEs with SI and SB, with evidence that PLEs at baseline were associated with worsening SI and SB over time, including a transition from SI to SB (ß = 0.032, FDRp = 0.002). Exploratory analyses showed consistent evidence for strengthened associations over time for higher delusional ideation with both SI and SB (ßs > 0.04, FDRps < 0.001), and for perceptual distortions with SB (ßs = 0.046, FDRp < 0.001). When accounting for general psychopathology, for SB, the strengthened associations over time was significantly stronger for PLEs (ß = 0.053, FDRp < 0.001) compared to general psychopathology (ß = 0.022, FDRp = 0.01). CONCLUSIONS: The present study indicates both SI and SB show strengthened associations with PLEs over time, and that baseline PLEs may predict worsening of suicidality over time. The findings are important clarifications about the nature of the associations between youth-reported PLEs and suicidality over time.

Pathways from developmental vulnerabilities in early childhood to schizotypy in middle childhood.

OBJECTIVES: Childhood disturbances in social, emotional, language, motor and cognitive functioning, and schizotypy have each been implicated as precursors of schizophrenia-spectrum disorders. We investigated whether relationships between early childhood developmental vulnerabilities and childhood schizotypy are mediated by educational underachievement in middle childhood. METHODS: Participants were members of a large Australian (n = 19,216) population cohort followed longitudinally. Path analyses were used to model relationships between developmental vulnerabilities at age ~5 years, educational underachievement from ages ~8 to 10 years and three distinct profiles of schizotypy at age ~11 years (true, introverted and affective schizotypy). RESULTS: Early childhood developmental vulnerabilities on five broad domains (related to physical, emotional, social, cognitive and communication development) were associated with schizotypy profiles in middle childhood. Educational underachievement in middle childhood was associated with all schizotypy profiles, but most strongly with the true schizotypy profile (OR = 3.92, 95% CI = 3.12, 4.91). The relationships between schizotypy profiles and early childhood developmental vulnerabilities in 'language and cognitive skills (school-based)' and 'communication skills and general knowledge' domains were fully mediated by educational underachievement in middle childhood, and the relationships with early childhood 'physical health and well-being' and 'emotional maturity' domains were partially mediated. CONCLUSION: Developmental continuity from early childhood developmental vulnerabilities to schizotypy in middle childhood is mediated by educational underachievement in middle childhood. While some domains of early developmental functioning showed differential relationships with distinct schizotypy profiles, these findings support a developmental pathway to schizotypy in which cognitive vulnerability operates from early childhood through to middle childhood.

Cumulative environmental risk in early life is associated with mental disorders in childhood.

BACKGROUND: No single environmental factor is a necessary or sufficient cause of mental disorder; multifactorial and transdiagnostic approaches are needed to understand the impact of the environment on the development of mental disorders across the life course. METHOD: Using linked multi-agency administrative data for 71 932 children from the New South Wales Child Developmental Study, using logistic regression, we examined associations between 16 environmental risk factors in early life (prenatal period to <6 years of age) and later diagnoses of mental disorder recorded in health service data (from age 6 to 13 years), both individually and summed as an environmental risk score (ERS). RESULTS: The ERS was associated with all types of mental disorder diagnoses in a dose-response fashion, such that 2.8% of children with no exposure to any of the environmental factors (ERS = 0), compared to 18.3% of children with an ERS of 8 or more indicating exposure to 8 or more environmental factors (ERS ⩾ 8), had been diagnosed with any type of mental disorder up to age 13-14 years. Thirteen of the 16 environmental factors measured (including prenatal factors, neighbourhood characteristics and more proximal experiences of trauma or neglect) were positively associated with at least one category of mental disorder. CONCLUSION: Exposure to cumulative environmental risk factors in early life is associated with an increased likelihood of presenting to health services in childhood for any kind of mental disorder. In many instances, these factors are preventable or capable of mitigation by appropriate public policy settings.

Self-reported mental health of children known to child protection services: an Australian population-based record linkage study.

Maltreated children are vulnerable to adverse mental health outcomes. Information about how children's mental health needs vary according to different levels of child protection contact (potentially culminating in out-of-home care [OOHC]) is valuable for the effective provision of services. This study aimed to examine associations between different levels of contact with child protection services before the age of 10 years and self-reported mental health difficulties at age 11 years. Participants (n = 26,960) were drawn from the New South Wales Child Development Study, a multiagency, multigenerational, longitudinal record linkage study that combines administrative records with cross-sectional survey data. We examined associations between four levels of child protection response (non-threshold reports, unsubstantiated reports, substantiated reports, OOHC; each relative to no report) and six domains of self-reported mental health difficulties (including internalising and externalising symptoms, and psychotic-like experiences). All levels of contact with child protection services were associated with increased odds of mental health difficulties in all domains. Children who had been placed in OOHC and children with substantiated reports had the highest odds of reporting clinical levels of mental health difficulties; 48.1% of children with an OOHC placement and 45.6% of those with substantiated child protection reports showed clinical levels of mental health difficulties in at least one domain. Children with child protection reports that were unsubstantiated, or determined not to meet the threshold for risk-of-significant harm, were also at increased risk of mental health difficulties in middle childhood. These findings underscore the importance of early detection and intervention for all children at risk of maltreatment.

Early childhood developmental vulnerability associated with parental mental disorder comorbidity.

OBJECTIVES: Parental mental health has a profound influence on the mental health and well-being of their offspring. With comorbid mental disorders generally the rule rather than the exception, increased knowledge of the impact of parental mental disorder comorbidity on early child development may facilitate improved targeting and delivery of early intervention for vulnerable offspring. METHODS: Participants were 66,154 children and their parents in the New South Wales Child Development Study - a prospective, longitudinal, record-linkage study of a population cohort of children born in NSW between 2002 and 2004. Early childhood developmental vulnerability was assessed at age ~5 years using the Australian Early Development Census, and information on parental mental disorders was obtained from administrative health records. Binomial and multinomial logistic regression were used to assess the relationship between parental mental disorders and early childhood developmental vulnerability on emotional and behavioural domains, as well as membership of latent developmental risk classes reflecting particular classes of vulnerability. RESULTS: Multiple diagnoses of mental disorders in mothers and fathers were associated with an increased likelihood of early childhood emotional and behavioural developmental vulnerability in offspring, relative to parents without mental disorder. The likelihood of offspring vulnerability increased with the number of parental comorbidities, particularly maternal comorbidities. CONCLUSION: Early childhood developmental vulnerability was strongly associated with parental mental ill-health, with the strength of associations increasing in line with a greater number of mental disorder diagnoses among mothers and fathers. New and expectant parents diagnosed with multiple mental disorders should be prioritised for intervention, including attention to the developmental well-being of their offspring.

A Deeper Dive Into the Relation Between Psychotic-like Experiences and Suicidal Ideation and Behaviors in Children Across the United States.

BACKGROUND AND HYPOTHESIS: Children who endorse psychotic-like experiences (PLEs) appear to be at a greater risk for suicidal ideation and behavior (SI/SB) compared to their peers who do not endorse PLEs. Despite evidence of differential relations among subtypes of PLEs and SI/SB, the research on which PLE subtypes produce the strongest associations remains mixed. Further, though there is evidence that general psychological distress may help explain the relation between PLEs and SI/SB, no research has investigated the role of distress specific to PLEs in this association. STUDY DESIGN: The present study sought to assess the associations among individual Prodromal Questionnaire-Brief Child Version (PQ-BC) items and SI/SB, as well as to explore the role of distress associated with PLEs as a mediator and/or moderator in a demographically diverse sample of children across the United States (N = 11 875). STUDY RESULTS: Results revealed that individual items of the PQ-BC may be differentially predictive of lifetime SI (ßs = 0.000-0.098) and SB (ßs=0.002-0.059), even when controlling for sociodemographic variables, internalizing symptoms, and traumatic experiences, with particularly strong associations observed among items indexing thought control, auditory hallucinations, suspiciousness, and nihilistic thinking/dissociative experiences. Item 13, nihilistic thinking/dissociative experiences, displayed the strongest effect sizes. Findings from moderation and mediation models provided evidence consistent with distress as both a partial mediator and moderator of the relation between total PLEs and individual PQ-BC items with SI and SB. CONCLUSIONS: Distress specific to PLEs may be an important modifiable risk factor to target in suicide assessment, prevention, and intervention efforts.

Parental and community risk factors for childhood self-harm thoughts and behaviours.

BACKGROUND: Childhood self-harm is rare but increasing in frequency. Little is known about risk factors specifically for self-harm in preteen children. METHODS: We examined self-harm thoughts and behaviours in children aged 3-14 years in association with parental and community-level risk factors, using a large general population-based record linkage sample (n = 74,479). RESULTS: Parental factors were strongly associated with childhood self-harm, with over three-quarters of children with self-harm having a parent with a history of mental disorder and/or criminal offending. Community-level factors (socioeconomic deprivation, remote or regional location, and neighbourhood crime rate) were not associated with childhood self-harm after adjustment for confounding factors. LIMITATIONS: Measures of self-harm thoughts and behaviours derived from administrative data likely underestimate the prevalence of self-harm in the population. CONCLUSIONS: Intergenerational transmission of risk factors is likely an important contributor to childhood self-harm.

Developmental profiles of schizotypy in the general population: A record linkage study of Australian children aged 11-12 years.

OBJECTIVES: The detection of young people at high risk for psychotic disorders has been somewhat narrowly focused on overt symptom-based markers that reflect mild reality distortion (e.g., psychotic-like experiences), or prodromal syndromes that are proximal to psychosis onset. The concept of schizotypy represents a broader framework for investigating risk for schizophrenia (and other disorders) in childhood, before the onset of prodromal or overt symptoms. We sought to detect profiles of risk for psychosis (schizotypy) in a general population sample of 22,137 Australian children aged 11-12 years, and to determine early life risk factors associated with these profiles from data available in linked records (registers). METHODS: Fifty-nine self-reported items were used as indicators of schizotypy across six broad domains; z-scores for each domain were subjected to latent profile analyses (LPA). A series of multinomial logistic regressions was used to examine the association between resulting profile (class) membership and several childhood and parental risk factors, and the proportion of children with mental disorders among each schizotypy profile was examined. RESULTS: The LPA revealed three person-centred profiles referred to as True Schizotypy (n = 1,323; 6.0%), Introverted Schizotypy (n = 4,473; 20.2%), and Affective Schizotypy (n = 4,261; 19.2%), as well as a group of children showing no risk (n = 12,080; 54.6%). Prior exposure to perinatal and familial adversities including childhood maltreatment, as well as poor early childhood development and academic functioning, was variously associated with all risk groups. There was a higher proportion of childhood mental disorder diagnoses among children in the True Schizotypy group, relative to other profiles. CONCLUSION: Subtle differences in the pattern of exposures and antecedents among schizophrenia liability profiles in childhood may reflect distinct pathogenic pathways to psychotic or other mental illness. PRACTITIONER POINTS: Children aged 11-12 years report characteristics of schizotypy which can be classified into three distinct profiles that may represent different pathological processes towards later mental ill-health. Early life exposure to perinatal and familial adversities including childhood maltreatment, early childhood developmental vulnerability, and poor academic functioning predict membership in all three childhood schizotypy profiles. Latent liability for schizophrenia (and potentially other mental disorders) may be represented by different profiles of functioning observable in childhood.

Sluggish Cognitive Tempo and Daytime Sleepiness Mediate Relationships Between Sleep and Academic Performance.

OBJECTIVE: Sleep difficulties, daytime sleepiness, and sluggish cognitive tempo (SCT) are associated with impairments in academic performance. SCT refers to symptoms of sluggishness, tiredness/lethargy, and slowed thinking/processing, but despite symptom overlap with sleepiness, research examining interrelations of SCT with sleep and daytime sleepiness is limited. The aims of this study were to evaluate the relationship between SCT and daytime sleepiness and to examine pathways between sleep, daytime sleepiness, SCT, and academic performance. METHOD: Participants were a community sample of 1628 parents/caregivers of children aged between 6 and 10 years who completed questionnaires about their child's behavior, sleep, and academic performance. Confirmatory factor analysis was used to examine whether SCT was distinct from daytime sleepiness. Then, structural equation modeling was used to examine direct and indirect pathways between sleep (sleep-disordered breathing [SDB] symptoms, sleep duration, and latency), daytime sleepiness, SCT, and academic performance in reading, writing, and math. RESULTS: SCT and daytime sleepiness were distinct but moderately correlated (r = 0.33, p ≤ 0.001). Sleep, in particular SDB symptoms, predicted increased SCT and daytime sleepiness. SCT was directly and negatively associated with all domains of academic performance, daytime sleepiness was associated with poorer reading performance, and longer sleep duration was directly associated with poorer math performance. SCT and, to a lesser extent, daytime sleepiness mediated effects of sleep on academic performance. CONCLUSION: SCT symptoms are important for understanding how sleep difficulties affect academic performance in children. Sleep, daytime sleepiness, and SCT are interrelated but distinct factors that affect children's academic performance.