Sleep habits in children with attention-deficit/hyperactivity disorder predominantly inattentive type and associations with comorbid psychopathology symptoms

Sleep insufficiency and bedtime irregularity in children with ADHD: A population-based analysis

BACKGROUND

Sleep is impaired in children with attention-deficit/hyperactivity disorder (ADHD). However, population-based examination of indicators of sleep insufficiency and bedtime irregularity is limited. This investigation examined associations between ADHD, weeknight sleep insufficiency, and bedtime irregularity in a nationally-representative child sample, and indicators of these sleep outcomes in ADHD.

METHODS

Parents of children aged 3-17 years with ADHD (n = 7671) were surveyed through the 2020-2021 National Survey of Children's Health. Inverse probability of treatment weighting generated a weighted matched control sample (n = 51,572). Weighted generalized linear models were performed without and with age-stratification to examine associations between ADHD and sleep, adjusting for sociodemographics in the full sample, and between nineteen sociodemographic and clinical variables and sleep in ADHD.

RESULTS

Having ADHD was associated with increased odds of sleep insufficiency and bedtime irregularity relative to controls, even after adjusting for sociodemographic variables. In ADHD, older age was associated with lower sleep insufficiency and greater bedtime irregularity. Black race, increased poverty, higher ADHD severity, depression, and increased screen time were associated with greater sleep insufficiency and bedtime irregularity. Adverse childhood experiences (ACEs) were associated with greater sleep insufficiency. Behavioral/conduct problems, female sex, and absence of both ADHD medication use and ASD diagnosis were associated with poorer bedtime irregularity. Age-stratified results are reported in text.

CONCLUSIONS

Children with ADHD face heightened risk for insufficient sleep and irregular bedtimes. Findings suggest intervention targets (e.g., Black race, poverty, depression, screen time) to improve both sleep insufficiency and bedtime irregularity. Results highlight ACEs and behavioral/conduct problems as targets to improve sleep insufficiency and bedtime regularity, respectively. Age-stratified findings are discussed.

"Tell Me More About Your Child's Sleep": A Qualitative Investigation Of Sleep Problems In Children With ADHD

OBJECTIVE

To investigate parental experiences and perceptions of sleep problems in their children with Attention Deficit Hyperactivity Disorder (ADHD), the perceived impacts of sleep problems and coping strategies deployed by parents.

METHODS

Semi-structured interviews with twenty-six parents of pre-adolescent children with a diagnosis of ADHD, followed by thematic analysis of the interview transcripts.

RESULTS

Three themes were generated from the data: Children's Sleep Difficulties; Impacts of Children's Sleep; and Improving Children's Sleep. Sleep initiation problems in children with ADHD were commonly reported by parents, were perceived to be linked in a bidirectional manner with executive and emotional problems, and were reported as being disruptive to parental sleep. Some parents reported that their children's sleep problems were the initial prompt that lead to a diagnosis of ADHD. Parents reported utilizing a range of coping strategies to mitigate sleep problems, such as controlling the bedroom sensory environment and using emotional "wind down" as part of the bedtime routine. Some parents endorsed a beneficial effect of melatonin on their children's sleep.

CONCLUSIONS

Sleep problems in children with ADHD were perceived as important issues by parents. Equipping parents with evidence-based strategies for the management of their children's sleep may lead to benefits for the children, parents and wider household.

Bibliometric Trends and Thematic Areas in Research on Cognitive Disengagement Syndrome in Children: A Comprehensive Review

This study aims to explore trends and principal research areas in the literature on Cognitive Disengagement Syndrome (CDS) in children aged 0-17 from a macro perspective. A total of 236 studies, selected based on inclusion and exclusion criteria from the Web of Science and Scopus databases, formed the data source for this research. We conducted a bibliometric analysis to examine the growth of CDS literature and to identify the most productive countries, relevant journals and publications, and trending topics. Additionally, through content analysis, we identified general research themes, sample trends, and methodologies used in these studies. Our findings reveal that the relatively new field of CDS research is expanding. Our thematic analysis shows that the literature on CDS covers a broad spectrum of research topics, addressing various facets of the syndrome and identifying current research themes. The existing studies highlight the complex nature of CDS and its diverse cognitive, psychological, and neurological impacts. Our results also suggest that while research is more prevalent in certain age groups, there is a need to encompass a wider demographic range, considering CDS's potential impact across different life stages. This bibliometric analysis offers a comprehensive review of the current knowledge in the CDS field, providing a valuable resource for researchers. Our analyses and findings can guide future research in this area and suggest approaches for broader study frameworks. It is anticipated that ongoing and future research in the CDS field will incorporate these insights to more effectively address the syndrome's varied aspects and consequences.

The Associations Between Sleep and Externalizing and Internalizing Problems in Children and Adolescents with Attention-Deficit/Hyperactivity Disorder: Empirical Findings, Clinical Implications, and Future Research Directions

Sleep problems are common in youth with attention-deficit/hyperactivity disorder (ADHD). Externalizing and internalizing problems contribute to dysfunction in youth with ADHD and are amplified by disrupted sleep. This objective of this article is to synthesize empirical studies that examined the associations between sleep and internalizing or externalizing problems in individuals with ADHD. The main findings are that sleep problems precede, predict, and significantly contribute to the manifestation of internalizing and externalizing behavior problems among children and adolescents with ADHD. Clinicians should assess sleep and integrate sleep interventions into the management of youth with ADHD.

Understanding the Impact of Insufficient Sleep in Children with Behavior Problems on Caregiver Stress: Results from a U.S. National Study

Research indicates strong connections between child ADHD, child ODD/CD, and sleep. Children experiencing these concerns also have caregivers who report feeling more stress. However, no studies have examined how child ADHD and ODD/CD interact together and with insufficient sleep to potentially exacerbate caregiver stress. Data were acquired from the 2018/2019 National Survey of Children's Health, a nationally representative survey of parents or caregivers conducted across the United States (U.S.). The current study used data for children 6-17 years old with a final analytic sample size of 41,541, representing a total of 47,357,862 U.S. youth. Overall child ADHD and ODD/CD were each uniquely associated with increased caregiver stress, while adequate child sleep duration was related to decreased caregiver stress. However, these findings were qualified by a significant two-way interaction that revealed that caregiver stress among children with comorbid ADHD and ODD/CD was not significantly greater than that of children with ODD/CD alone. Significant interactions between sleep and ODD/CD on caregiver stress were generally not observed, except potentially in females with ADHD. Our findings underscore the importance of considering strategies to reduce both youth symptoms and caregiver stress simultaneously. Additionally, ensuring adequate sleep for all children is recommended.

Cognitive Disengagement Syndrome and Child Sleep Problems in ADHD, Anxiety and Depression

The main objective of this study was to analyse the relationship and differential contribution of Cognitive Disengagement Syndrome (CDS) and sleep problems in children in different psychopathological measures. A total of 1133 participants (612 fathers/mothers and 521 children aged 7-13 years in Years 3-6 of Primary Education) completed the scales on CDS, sleep problems, depression (DEP), anxiety (ANX) and attention deficit and hyperactivity disorder (ADHD). Similar and significant correlations were identified in the measures of CDS and sleep problems between fathers and mothers, obtaining a high coefficient between the two parents. However, weak correlations were found between fathers/mothers and children. The scores of CDS and the sleep disturbance scale for children (SDSC) significantly predicted the internalising measures and ADHD, especially between SDSC and DEP. It was confirmed that sleep problems had a greater presence in the group of children with the highest ADHD scores, and especially in CDS and ADHD jointly. To conclude, the data indicate the importance of sleep problems in understanding CDS and its relationship with other psychopathological measures, especially ADHD, although to a greater extent with internalising symptoms, especially DEP.

A multi-method examination of sluggish cognitive tempo in relation to adolescent sleep, daytime sleepiness, and circadian preference

BACKGROUND

The field's understanding of the association between sluggish cognitive tempo (SCT) and sleep is severely limited by the lack of multi-method and multi-informant research designs that move beyond global ratings, often focused on a limited number of sleep-related domains, such as daytime sleepiness. The current study begins to address these limitations by using actigraphy, daily sleep diary, and self- and parent-report global ratings of sleep in adolescents, a developmental period marked by changes in SCT, sleep, and circadian function. As SCT and sleep are also associated with ADHD symptoms, we tested these associations in a sample of adolescents with and without ADHD.

METHODS

Adolescents (N = 302; M age = 13.17 years, 44.7% female) with (n = 162) and without ADHD (n = 140) and parents completed global ratings of sleep and daytime sleepiness, and adolescents completed a measure of circadian preference. Adolescents also wore actigraphs for approximately two weeks, during which daily diaries were completed.

RESULTS

Above and beyond demographic characteristics (i.e., sex, race, and family income), pubertal development, medication use, and ADHD group status, adolescents' self-reported SCT symptoms were uniquely associated with shorter sleep duration and later sleep onset per both actigraphy and daily diary. SCT symptoms were also uniquely associated with longer sleep onset latency and poorer overall sleep (per daily diary), more sleep/wake problems and daytime sleepiness (per adolescent rating), more difficulties initiating and maintaining sleep (per parent rating), and later eveningness preference (per adolescent rating). Nearly all significant effects remained in sensitivity analyses controlling for adolescent- or parent-reported ADHD symptom dimensions.

CONCLUSIONS

Findings provide the strongest evidence to date for SCT being uniquely linked to poorer sleep, greater daytime sleepiness, and a later evening circadian preference across subjective and objective measures. Longitudinal studies are needed to evaluate predictive and bidirectional associations.

A Systematic Review of Sleep and Circadian Rhythms in Children with Attention Deficit Hyperactivity Disorder

OBJECTIVE

Children and adults with ADHD often report sleep disturbances that may form part of the etiology and/or symptomatology of ADHD. We review the evidence for sleep changes in children with ADHD.

METHODS

Systematic review with narrative synthesis assessing sleep and circadian function in children aged 5 to 13 years old with a diagnosis of ADHD.

RESULTS

148 studies were included for review, incorporating data from 42,353 children. We found that sleep disturbances in ADHD are common and that they may worsen behavioral outcomes; moreover, sleep interventions may improve ADHD symptoms, and pharmacotherapy for ADHD may impact sleep.

CONCLUSION

Sleep disturbance may represent a clinically important feature of ADHD in children, which might be therapeutically targeted in a useful way. There are a number of important gaps in the literature. We set out a manifesto for future research in the area of sleep, circadian rhythms, and ADHD.

Systematic Review: Assessment of Sluggish Cognitive Tempo Over the Past Decade

OBJECTIVE

To conduct a systematic review of the measures designed to assess sluggish cognitive tempo (SCT) since the first SCT scale using careful test-construction procedures was published in 2009.

METHOD

MEDLINE (PubMed), Embase, PsychINFO, and Web of Science databases were searched from September 2009 through December 2019. Articles reporting on reliability (internal consistency, test-retest, and interrater reliability), structural validity (an aspect of construct validity focused on items' convergent and discriminant validity), concurrent and longitudinal external validity, invariance, or intervention/experimental findings were included.

RESULTS

Full criteria for data extraction and inclusion were met by 76 studies. Nine measures for assessing SCT were identified (7 assessing parent report, teacher report, and/or self-report in children and 2 assessing self-report and/or collateral informant report in adults). Each measure demonstrated acceptable to excellent reliability. All or at least the majority of SCT items on each measure also had structural validity (high loadings on an SCT factor and low loadings on an attention-deficit/hyperactivity disorder [ADHD] inattention factor). Studies have supported the invariance of SCT across sex and time, and there is initial evidence of invariance across informants, youths with ADHD and youths without ADHD, and ADHD presentations. The Child and Adolescent Behavior Inventory (CABI), Child Concentration Inventory, Second Edition (CCI-2), and Barkley Adult ADHD Rating Scale-IV (BAARS-IV) have particularly strong support for assessing parent/teacher-reported, youth self-reported, and adult self-reported SCT, respectively.

CONCLUSION

The SCT measures included in this review share numerous positive properties, have promising psychometric support, and have proven useful for examining the external correlates of SCT across the life span. Although substantial progress has been made over the last decade, work remains to be done to further improve the assessment of SCT and key directions for future research are provided.

The Associations Between Sleep and Externalizing and Internalizing Problems in Children and Adolescents with Attention-Deficit/Hyperactivity Disorder: Empirical Findings, Clinical Implications, and Future Research Directions

Sleep problems are common in youth with attention-deficit/hyperactivity disorder (ADHD). Externalizing and internalizing problems contribute to dysfunction in youth with ADHD and are amplified by disrupted sleep. This objective of this article is to synthesize empirical studies that examined the associations between sleep and internalizing or externalizing problems in individuals with ADHD. The main findings are that sleep problems precede, predict, and significantly contribute to the manifestation of internalizing and externalizing behavior problems among children and adolescents with ADHD. Clinicians should assess sleep and integrate sleep interventions into the management of youth with ADHD.

Attention-Deficit/Hyperactivity Disorder Predominantly Inattentive Subtype/Presentation: Research Progress and Translational Studies

Research on the predominantly inattentive attention-deficit/hyperactivity disorder (ADHD-PI) subtype/presentation is important given its high prevalence, but paradoxically it is under-recognized and undertreated. The temporal stability of the inattention symptom could impact the high worldwide prevalence of ADHD-PI. Some evidence suggests differences in the nature of attentional deficit in ADHD-PI vs. that in other subtypes. Impairments in neuropsychological, neurocognitive, and social functioning are also evident in ADHD-PI, which could be specific to the subtype (e.g., processing speed, social perception, and skills), or differ from others in severity. Neuroimaging studies have also revealed ADHD-PI-specific neuropathological abnormalities and those that are shared with other subtypes. ADHD-PI is highly comorbid with learning and internalizing (e.g., anxiety and depression) disorders. There is no solid evidence for ADHD-PI-specific genetic etiologies and differential responses of subtypes to ADHD medications. Translational studies have used the Wistar Kyoto/NCrl substrain which requires further characterizations as an ADHD-PI model. Overall, ADHD-PI research has been conducted in the context of the Diagnostic and Statistical Manual, which arguably does not conform to the widely recognized "dimensional" view of ADHD. The Research Domain Criteria has been proposed to provide a novel framework for understanding the nature of neuropsychiatric illnesses and ultimately improve their diagnosis and treatment.

Sluggish Cognitive Tempo and ADHD Symptoms in a Nationally Representative Sample of U.S. Children: Differentiation Using Categorical and Dimensional Approaches

A nationally representative sample of U.S. children was used to determine the empirical and clinical differentiation of sluggish cognitive tempo (SCT) and attention-deficit/hyperactivity disorder (ADHD) symptoms using both categorical and dimensional approaches. Mothers of children (N = 2,056, M± SD_age = 8.49 ± 2.15 years, 49.3% girls) completed measures of SCT, ADHD, oppositional defiant disorder (ODD), anxiety, depression, sleep difficulties, daily life executive functioning, conflicted shyness, friendship difficulties, and social and academic impairment. Scores greater than the top 5% on SCT and ADHD measures were used to create SCT-only (n = 53, 2.58%), ADHD-only (n = 93, 4.52%), SCT+ADHD (n = 49, 2.38%), and comparison (n = 1,861, 90.52%) groups. Fifty-two percent of the SCT group did not qualify for the ADHD group, whereas 65% of the ADHD group did not qualify for the SCT group. The SCT-only group had higher levels of anxiety, depression, conflicted shyness, and sleep difficulties than the ADHD-only group. In contrast, the ADHD-only group had greater executive functioning deficits and higher ODD than the SCT-only group. SCT-only and ADHD-only groups showed similar levels of friendship, social, and academic impairment. Similar findings emerged when using structural regression analyses to determine the unique clinical correlates of SCT and ADHD dimensions. This is only the second study to examine the distinction of clinically-elevated SCT from ADHD in a national sample of children and extends previous findings to a broader array of functional outcomes. Normative information on the SCT scale also provides a validated rating scale to advance research and clinical care.

Event-related potentials and behavior performance scores in children with sleep-disordered breathing

OBJECTIVE

To explore impaired cognition characteristics and abnormal behavior in children with Sleep-Disordered Breathing (SDB) via Event-Related Potentials (ERPs), continuous performance testing (CPT), and the Child Behavior Checklist (CBCL).

METHODS

A total of 108 children aged 6-8 years old were recruited, including fifty-four children (28 boys) with SDB and fifty-four normal children (28 boys). CBCL and Chinese version of the OSA-18 questionnaire were administered. Nineteen children with SDB (OSA-18 questionnaire value >60) and Nineteen normal children completed a CPT task. ERP was extracted using the BESA software.

RESULTS

No significant differences in the correct number, reaction time, or the number of commission error were noted between the CPT of the two groups (P > 0.05). The ERP Go-P3 amplitudes at F3, Fz and F4 of the SDB group were significantly higher than those of the control group (P < 0.05). The NoGo-N2 amplitudes at F3 and Fz of the SDB group were significantly lower than those of the control group (P < 0.05). The Fz and F4 Go-P3 and FZ NoGo-P3 latency of the SDB group were significantly longer than those of the control group (P < 0.05). However, among boys, the CBCL scores of the SDB group including the subscores, schizo, somatic complaints, compulsion, aggression, and hyperactivity, as well as the total score, were significantly higher than the control group (all P < 0.05).

CONCLUSION

Children with SDB demonstrate significant functional deficits in regard to conflict monitoring, attention, and inhibition. The frontal region is the primary area of dysfunction, especially in the left brain region, and inhibition function dysfunction may be a common pathogenesis of SDB and ADHD. Moreover, boys with SDB may exhibit more behavior problems when compared to girls.

Advancing the study of sluggish cognitive tempo via DSM, RDoC, and hierarchical models of psychopathology

Sluggish cognitive tempo (SCT) is separable from attention-deficit/hyperactivity disorder (ADHD) and other psychopathologies, and growing evidence demonstrates SCT to be associated with impairment in both children and adults. However, it remains unclear how SCT should optimally be conceptualized. In this article, we argue that multiple models of psychopathology should be leveraged to make substantive advances to our understanding of SCT. Both categorical and dimensional approaches should be used, including the Diagnostic and Statistical Manual of Mental Disorders (DSM) nosology, the Research Domain Criteria (RDoC) initiative, and hierarchical models of psychopathology. Studies are needed to determine whether individuals categorized with SCT can be reliably identified and differentiated from individuals without SCT in pathophysiological, neuropsychological, behavioral, and daily life functioning. Studies are also needed to evaluate the validity and utility of SCT as a transdiagnostic and dimensional construct. In considering SCT as a dimensional and potentially transdiagnostic construct, we describe ways in which SCT might be examined within the RDoC framework, including negative valence systems, cognitive systems, and arousal/regulatory systems, as well as within hierarchical models of psychopathology. Conceptualizing SCT within both categorical and dimensional models of psychopathology will help to better understand the causes, developmental pathways, and clinical implications of SCT, both as a construct in its own right and also in relation to other psychopathologies.

The impact of comorbid mental health symptoms and sex on sleep functioning in children with ADHD

Children with attention-deficit/hyperactivity disorder (ADHD) display more sleep problems than their peers, but it remains unclear whether comorbid mental health symptoms [i.e., anxiety, depression, oppositional-defiant disorder (ODD)] are uniquely related to sleep functioning. It is also largely unknown whether boys and girls with ADHD differ in their sleep functioning. This study (1) examined whether boys or girls with ADHD differ in their sleep functioning, (2) evaluated comorbid symptoms as uniquely related to sleep functioning domains, and (3) explored whether sex moderated associations between comorbid symptoms and sleep. Participants were 181 children (ages 7-13; 69% male; 82% White) diagnosed with ADHD. Parents completed measures assessing their child's ADHD symptoms, comorbid symptoms, and sleep functioning. Girls had poorer sleep functioning than boys across most sleep functioning domains. Sixty percent of children met cutoff criteria for having sleep problems, though rates differed significantly between girls (75%) and boys (53%). No differences in rates of sleep problems were found between ADHD subtypes/presentations or between younger and older children. In path models including ADHD and comorbid symptom dimensions, anxiety symptoms were uniquely associated with increased bedtime resistance and sleep anxiety, ADHD hyperactive-impulsive symptoms were associated with more night wakings and more parasomnia behaviors, and ODD and depressive symptoms were associated with shorter sleep duration. Depression was also uniquely associated with increased daytime sleepiness and overall sleep problems. Sex did not moderate associations between comorbid symptoms and sleep problems. This study provides important preliminary evidence that girls with ADHD experience more sleep problems than boys with ADHD. Findings also demonstrate that the associations between comorbid symptoms and sleep functioning in children with ADHD vary based on both the specific symptoms and sleep domains examined.

Evaluating the Structure of Sluggish Cognitive Tempo Using Confirmatory Factor Analytic and Bifactor Modeling With Parent and Youth Ratings

The primary goals of this study were to evaluate the dimensionality of the Penny et al. Sluggish Cognitive Tempo Scale and to compare model fits for parent- and youth self-report versions. Participants were 262 young adolescents (ages 10-15) comprehensively diagnosed with attention-deficit/hyperactivity disorder. Both confirmatory factor analysis (CFA) and bifactor modeling were used to determine if the proposed three-factor structure previously identified through exploratory factor analysis could be confirmed. Results showed that although the three-factor CFA had better fit statistics than a one- or two-factor CFA, the bifactor model was the best-fitting model for both parent report and self-report. This implies that Sluggish Cognitive Tempo Scale is best conceptualized as having an underlying general factor, with three specific factors that may represent different etiologies. Importantly, results also showed low-to-moderate correlations between raters and equivalent or better fit statistics for self-report in comparison with parent report.

Effects of Methylphenidate on Sleep Functioning in Children with Attention-Deficit/Hyperactivity Disorder

OBJECTIVE

To examine the effects of stimulant medication on the sleep functioning of children with attention-deficit/hyperactivity disorder (ADHD) and identify predictors of sleep problems as a side effect of taking stimulant medication.

METHOD

One hundred sixty-three stimulant-naïve children (72% boys) aged 7 to 11 years diagnosed with ADHD (120 with ADHD predominantly inattentive type, 43 with ADHD combined type) participated in a 4-week, randomized, double-blind, placebo-controlled trial of once-daily (long-acting) methylphenidate (MPH). Parents completed weekly side-effect ratings including an item related to sleep problems.

RESULTS

Ten percent of patients had parent-rated sleep problems before the initiation of medication. Rates of parent-rated sleep problems during MPH titration generally increased with increasing MPH dose (placebo: 8%; low dose: 18%; medium dose: 15%; high dose: 25%). Differences emerged between children with (n = 16) or without (n = 147) preexisting sleep problems. Although 23% of children without preexisting sleep problems went on to have sleep problems at the highest MPH dose, only 37.5% of children with preexisting sleep problems still had sleep problems at the highest MPH dose. Lower weight and lower body mass index (BMI) were associated with increased sleep problems during MPH titration.

CONCLUSION

This study demonstrated a general association between increased MPH dose and increased sleep problems in children with ADHD, particularly for children of lower weight/BMI. However, a substantial proportion of children with preexisting sleep difficulties no longer had sleep problems on the highest MPH dose, which may help explain mixed findings reported to date in studies examining the impact of MPH on sleep functioning in children with ADHD and suggests that MPH dose titration should not be avoided solely on the basis of a child's premorbid sleep problems. Future research is needed to replicate and extend these findings to more specific domains of sleep functioning and to identify differences between children with persistent or improved sleep functioning as a result of MPH use.

Sluggish cognitive tempo in children referred to a pediatric Sleep Disorders Center: Examining possible overlap with sleep problems and associations with impairment

Research supports the distinctness of sluggish cognitive tempo (SCT) (e.g., mental confusion and slowed behavior/thinking) from other psychopathologies. However, the relation between SCT and sleep functioning has not been adequately studied. We examined the association between SCT and sleep functioning in 325 children (62% male) ages 6-10 years referred to a pulmonary-based, accredited Sleep Disorders Center. Correlations between caregiver ratings of SCT, other psychopathologies (i.e., inattention/hyperactivity, oppositionality, depression, anxiety), sleep functioning (both behavioral and organic symptoms), as well as sleep disorder diagnoses, were examined. Unique effects of SCT and other psychopathologies on sleep problem severity controlling for child demographics were assessed using regressions. Regression analyses were also conducted to examine the unique effects of SCT on impairment (i.e., academic difficulties, parenting stress, and other psychopathologies) controlling for child demographics, sleep problem severity, and other psychopathology symptoms. SCT was weakly to moderately correlated with most measures of sleep (rs = .07-.39) and moderately to strongly correlated with measures of daytime sleepiness (rs = .33 and .53). In the regression analyses, SCT was uniquely associated with greater sleep functioning severity and impairment in academic functioning. SCT was also uniquely associated with higher levels of depression and inattention/hyperactivity, but not anxiety, and negatively associated with oppositionality. Finally, SCT symptoms were uniquely associated with greater parent-child dysfunctional interaction. Findings demonstrate that SCT is related to, but not redundant with, sleep problems and daytime sleepiness specifically. Further, SCT remained associated with several domains of functional impairment in sleep-disordered children after controlling for clinically-relevant variables, highlighting the potential value in assessing SCT symptoms in children with sleep problems.

The Internal, External, and Diagnostic Validity of Sluggish Cognitive Tempo: A Meta-Analysis and Critical Review

OBJECTIVE

To conduct the first meta-analysis evaluating the internal and external validity of the sluggish cognitive tempo (SCT) construct as related to or distinct from attention-deficit/hyperactivity disorder (ADHD) and as associated with functional impairment and neuropsychological functioning.

METHOD

Electronic databases were searched through September 2015 for studies examining the factor structure and/or correlates of SCT in children or adults. The search procedures identified 73 papers. The core SCT behaviors included across studies, as well as factor loadings and reliability estimates, were reviewed to evaluate internal validity. Pooled correlation effect sizes using random effects models were used to evaluate SCT in relation to external validity domains (i.e., demographics, other psychopathologies, functional impairment, and neuropsychological functioning).

RESULTS

Strong support was found for the internal validity of the SCT construct. Specifically, across factor analytic studies including more than 19,000 individuals, 13 SCT items loaded consistently on an SCT factor as opposed to an ADHD factor. Findings also support the reliability (i.e., internal consistency, test-retest reliability, interrater reliability) of SCT. In terms of external validity, there is some indication that SCT may increase with age (r = 0.11) and be associated with lower socioeconomic status (r = 0.10). Modest (potentially negligible) support was found for SCT symptoms being higher in males than females in children (r = 0.05) but not in adults. SCT is more strongly associated with ADHD inattention (r = 0.63 in children, r = 0.72 in adults) than with ADHD hyperactivity-impulsivity (r = 0.32 in children, r = 0.46 in adults), and it likewise appears that SCT is more strongly associated with internalizing symptoms than with externalizing symptoms. SCT is associated with significant global, social, and academic impairment (r = 0.38-0.44). Effects for neuropsychological functioning are mixed, although there is initial support for SCT being associated with processing speed, sustained attention, and metacognitive deficits.

CONCLUSION

This meta-analytic review provides strong support for the internal validity of SCT and preliminary support for the external validity of SCT. In terms of diagnostic validity, there is currently not enough evidence to describe SCT in diagnostic terms. Key directions for future research are discussed, including evaluating the conceptualization of SCT as a transdiagnostic construct and the need for longitudinal research.