New Research on the Complex Interaction of Sleep and ADHD

Childhood Physical Health and Attention Deficit/Hyperactivity Disorder: A Systematic Review and Meta-Analysis of Modifiable Factors

Although neurobiologic and genetic factors figure prominently in the development of attention deficit/hyperactivity disorder (ADHD), adverse physical health experiences and conditions encountered during childhood may also play a role. Poor health is known to impact the developing brain with potential lifelong implications for behavioral issues. In attempt to better understand the relationship between childhood physical health and the onset and presence of ADHD symptoms, we summarized international peer-reviewed articles documenting relationships between a select group of childhood diseases or health events (e.g., illnesses, injuries, syndromes) and subsequent ADHD outcomes among children ages 0-17 years. Drawing on a larger two-phase systematic review, 57 longitudinal or retrospective observational studies (1978-2021) of childhood allergies, asthma, eczema, head injury, infection, or sleep problems and later ADHD diagnosis or symptomatology were identified and subjected to meta-analysis. Significant associations were documented between childhood head injuries, infections, and sleep problems with both dichotomous and continuous measures of ADHD, and between allergies with dichotomous measures of ADHD. We did not observe significant associations between asthma or eczema with ADHD outcomes. Heterogeneity detected for multiple associations, primarily among continuously measured outcomes, underscores the potential value of future subgroup analyses and individual studies. Collectively, these findings shed light on the importance of physical health in understanding childhood ADHD. Possible etiologic links between physical health factors and ADHD are discussed, as are implications for prevention efforts by providers, systems, and communities.

Sleep problems in children with autism spectrum disorder and attention-deficit/hyperactivity disorder: A comparative study and effects on communication skills

Sleep disturbances are highly prevalent among children with neurodevelopmental disorders, like Autism Spectrum Disorder (ASD) and Attention-Deficit/Hiperactivity Disorder (ADHD). The first objective of this study is to examine the differences in sleep problems between a group of children with ASD without intellectual disabilities, a group with ADHD and a typically developing (TD) group. A second objective is aimed at analyzing the effects of sleep problems and symptom severity on their communication skills. Participants were 122 children between 7 and 12 years old distributed in three groups: 32 TD children, 47 children with ASD and 43 children with ADHD, matched on age and intelligence. Parents completed different questionnaires that measured sleep disturbances and communication skills. Findings show significant differences between the clinical groups and the TD group in most types of sleep disorders. Moreover, the group with ADHD showed significantly more sleep breathing disorders and hyperhidrosis in comparison with ASD and TD, as well as more total sleep problems. In contrast to ASD, the predictive power of sleep problems on communication difficulties was greater in the group with ADHD. The results of the mediation analysis indicate that in both groups, sleep problems partially mediate the relationship between symptoms and communication. This investigation highlights the need of considering sleep disorders when assessing communication skills in ASD and ADHD, given its indirect influence in this domain. Understanding the sleep dysfunctions of both conditions and their repercussions is crucial to develop adjusted interventions.

Health conditions in autism: Defining the trajectory from adolescence to early adulthood

Autistic adults, as compared to non-autistic adults, have increased rates of nearly all medical and psychiatric conditions. Many of these conditions begin in childhood, although few longitudinal studies have been conducted to examine prevalence rates of these conditions from adolescence into early adulthood. In this study, we analyze the longitudinal trajectory of health conditions in autistic youth, compared to age and sex-matched non-autistic youth, transitioning from adolescence into early adulthood in a large integrated health care delivery system. The percent and modeled prevalence of common medical and psychiatric conditions increased from age 14 to 22 years, with autistic youth having a higher prevalence of most conditions than non-autistic youth. The most prevalent conditions in autistic youth at all ages were obesity, neurological disorders, anxiety, and ADHD. The prevalence of obesity and dyslipidemia rose at a faster rate in autistic youth compared to non-autistic youth. By age 22, autistic females showed a higher prevalence of all medical and psychiatric conditions compared to autistic males. Our findings emphasize the importance of screening for medical and psychiatric conditions in autistic youth, coupled with health education targeted at this population, to mitigate the development of adverse health outcomes in autistic adults.

The role of inflammation in the prospective associations between early childhood sleep problems and ADHD at 10 years: findings from a UK birth cohort study

BACKGROUND

Several underlying mechanisms potentially account for the link between sleep and attention deficit and hyperactivity disorder (ADHD), including inflammation. However, studies so far have been cross sectional. We investigate (a) the association between early childhood sleep and probable ADHD diagnosis in childhood and (b) whether childhood circulating inflammatory markers mediate these prospective associations.

METHODS

Data from the Avon Longitudinal Study of Parents and Children were available for 7,658 10-year-old children. Parent-reported sleep duration, night awakening frequency and regular sleep routines were collected at 3.5 years. The Development and Wellbeing Assessment was administered to capture children with clinically relevant ADHD symptoms, or probable ADHD diagnosis. Blood samples were collected at 9 years, from which two inflammatory markers were obtained [interleukin-6 (IL-6) and C-reactive protein (CRP)]. Logistic regression analyses were applied to investigate the associations between sleep variables at 3.5 years and probable ADHD diagnosis at 10 years. Further, path analysis was applied to examine the potential mediating role of inflammation at 9 years (as measured by CRP and IL-6) in the associations between early sleep and ADHD at 10 years.

RESULTS

Less regular sleep routines (OR = 0.51, 95% CI = 0.28-0.93, p = .029), shorter nighttime sleep (OR = 0.70, 95% CI = 0.56-0.89, p = .004) and higher night awakening frequency (OR = 1.27, 95% CI = 1.06-1.52, p = .009) at 3.5 years were associated with higher odds of ADHD at 10 years. Further, IL-6 at 9 years, but not CRP, mediated the association between irregular sleep routines and ADHD (bias-corrected estimate, -0.002; p = .005) and between night awakening and ADHD (bias-corrected estimate, 0.002; p = .003).

CONCLUSIONS

Several sleep problems in early childhood constitute a risk factor for probable ADHD diagnosis at 10 years. Further, these associations are partially mediated by IL-6 at 9 years. These results open a new research vista to the pathophysiology of ADHD and highlight sleep and inflammation as potential preventative targets for ADHD.

Sleep Architecture and EEG Power Spectrum Following Cumulative Sleep Restriction: A Comparison between Typically Developing Children and Children with ADHD

No studies have looked at the effects of cumulative sleep restriction (CSR) on sleep architecture or the power spectrum of sleep EEG (electroencephalogram) in school-age children, as recorded by PSG (polysomnography). This is true for both typically developing (TD) children and children with ADHD (attention deficit/hyperactivity disorder), who are known to have more sleep difficulties. Participants were children (ages 6-12 years), including 18 TD and 18 ADHD, who were age- and sex-matched. The CSR protocol included a two-week baseline and two randomized conditions: Typical (six nights of sleep based on baseline sleep schedules) and Restricted (one-hour reduction of baseline time in bed). This resulted in an average of 28 min per night difference in sleep. Based on ANOVAs (analysis of variance), children with ADHD took longer to reach N3 (non-rapid eye movement), had more WASO (wake after sleep onset) (within the first 5.1 h of the night), and had more REM (rapid eye movement) sleep than TD children regardless of condition. During CSR, ADHD participants had less REM and a trend toward longer durations of N1 and N2 compared to the TD group. No significant differences in the power spectrum were found between groups or conditions. In conclusion, this CSR protocol impacted some physiological aspects of sleep but may not be sufficient to cause changes in the power spectrum of sleep EEG. Although preliminary, group-by-condition interactions suggest that the homeostatic processes in children with ADHD may be impaired during CSR.

Clinical Characteristics of Children With Tourette Syndrome With and Without Sleep Disorder

BACKGROUND

Sleep problems are common in children with Tourette Syndrome (TS). However, research regarding their demographic and clinical profile is limited.

METHODS

We examined characteristics of 114 children aged five to 17 years with a lifetime diagnosis of TS and compared children with sleep disorder (n = 32) and without sleep disorder (n = 82). Parent report from the 2014 National Survey of the Diagnosis and Treatment of ADHD and Tourette Syndrome provided demographics and clinical information, other diagnosed disorders, medication use, TS severity, and impairment.

RESULTS

More children with TS with sleep disorder were from households with lower parental education (P < 0.01) and poverty (P = 0.04); had other diagnoses (P = 0.03), including obsessive-compulsive disorder (P < 0.01), oppositional defiant disorder or conduct disorder (P < 0.01), attention-deficit/hyperactivity disorder (ADHD) (P = 0.02), and autism (P = 0.03); and had ever used TS medication (P = 0.01) than children with TS without sleep disorder. More children with TS with sleep disorder had severe TS symptoms (P <0.01), tic-related impairment (P<0.01), and severe ADHD symptoms (P < 0.01) compared with children with TS without sleep disorder.

CONCLUSIONS

Findings suggest greater parent-reported impact and tic-related interference in children with TS with sleep disorder compared with TS without sleep disorder. Results underscore the importance of monitoring and intervention for TS exacerbations, other diagnosed disorders, and medication use, and consideration of socioeconomic context in sleep disorder management and prevention in children with TS.

Links between excessive daytime sleepiness and EEG power and activation in two subtypes of ADHD

OBJECTIVES

This study aimed to replicate previously reported EEG characteristics between typically developing (TD) children and two subtypes of Attention Deficit Hyperactivity Disorder (ADHD) using a frontal, single-channel, dry-sensor portable EEG device, and explore whether differences are moderated by excessive daytime sleepiness (EDS).

METHODS

Children with ADHD Inattentive (ADHD-I) and ADHD Combined presentation (ADHD-C) and typically-developing (TD) children (N = 34 in each group) had frontal EEG recorded during eyes-closed resting, eyes-open resting, and focus tasks. Participants also completed the Children's Self-Report Sleep Patterns - Sleepiness Scale as a measure of EDS.

RESULTS

Consistent with previous literature, there were increases in frontal delta and theta power in the ADHD-C compared to ADHD-I and TD groups, in all conditions. Novel power and activation effects in ADHD subtypes, as well as significant group and EDS interactions for alpha and beta power were also found.

CONCLUSIONS

These findings highlight the importance of considering ADHD subtypes and EDS when exploring EEG characteristics, and have important implications for the diagnosis and treatment of children with ADHD.

Association of Parent-Rated Sleep Disturbances With Attention-Deficit/Hyperactivity Disorder Symptoms: 9-Year Follow-up of a Population-Based Cohort Study

OBJECTIVE

Symptoms of attention-deficit/hyperactivity disorder (ADHD) and sleep disturbances frequently co-occur, and can result in significant functional impairments that worsen quality of life. Despite a growing number of studies focusing on the association between sleep disturbances and ADHD symptoms over the last 20 years, the directionality of this association from childhood to early adulthood remains unclear.

METHOD

A sample of French parents (n = 1,055) were followed-up over a 9-year period. At children mean ages of 9, 13, and 18 years, parents were interviewed about their children's ADHD symptoms and sleep disturbances. Random-intercept cross-lagged panel models assessed the directionality of the association from childhood to early adulthood.

RESULTS

Parent-reported sleep disturbances at a mean age of 13 years predicted increased ADHD symptoms 5 years later. Additional analyses suggested that this effect might be limited to inattentive symptoms, and that ADHD symptoms at a mean age of 9 predicted increased sleep disturbances 4 years later.

CONCLUSION

The present study provides evidence of a directional longitudinal association between parent-reported sleep disturbances and ADHD symptoms from adolescence to early adulthood. Our results highlight the importance of identifying sleep disturbances and ADHD symptoms for the design of preventive interventions. Future studies investigating this association in children with a clinical diagnosis of ADHD have the potential to provide important information for clinical practice.

A literature review of sleep problems and neurodevelopment disorders

INTRODUCTION

Sleep is an incredibly complex process that goes beyond relaxing and body resting. Disturbance in sleep leads to several short-term and long-term consequences. Neurodevelopmental diseases such as "autism spectrum disorder" (ASDs), Attention-deficit hyperactivity disorder (ADHD), and intellectual disability commonly experience sleep disorders that affect their clinical presentation, daily function, and quality of life.

DISCUSSION

The incidence of sleep problems in ASD patients ranges from 32 to 71.5%, especially insomnia, while an estimated 25-50% of people with ADHD report having sleep issues in clinical settings. The incidence of sleep issues is widespread in persons with intellectual disabilities, reaching up to 86%. This article is a literature review covering the neurodevelopmental disorder interaction with sleep disorder and different management.

CONCLUSION

Disorders of sleep are key concerns in children with neurodevelopmental disorders. In this group of patients, sleep disorders are common and tend to be chronic. Recognizing and diagnosis of sleep disorders will enhance their function, response to treatment, and quality of life.

Effects of Sleep Extension on Inhibitory Control in Children With ADHD: A Pilot Study

Objective: Children with ADHD often have sleep complaints and cognitive deficits. The aim of this pilot study was to determine whether sleep extension improves inhibitory control, a primary cognitive deficit in ADHD. Method: Children with (n = 11) and without (n = 15) ADHD participated in a within-subject sleep extension intervention that targeted nocturnal sleep duration. Sleep was assessed with actigraphy and polysomnography. Inhibitory control was assessed with a Go/No-Go task. Results: For children without ADHD, there was a significant main effect of time, such that morning inhibitory control was 10% greater than evening inhibitory control. However, inhibitory control did not differ between the baseline and extension conditions in this group. For children with ADHD, although morning inhibitory control did not differ from evening inhibitory control, sleep extension improved inhibitory control by 13% overall. Conclusion: These results suggest that a sleep extension intervention improves inhibitory control in children with ADHD.

Prevalence, Patterns, and Predictors of Sleep Problems and Daytime Sleepiness in Young Adolescents With ADHD

Objective: The primary objective of this study was to evaluate the prevalence of multiple types of sleep problems in young adolescents with ADHD. Method: Adolescents comprehensively diagnosed with ADHD (N = 262) and their caregivers completed well-validated measures of sleep problems and daytime sleepiness. Participants also completed measures related to medication use, comorbidities, and other factors that could predict sleep problems. Results: Daytime sleepiness was by far the most common sleep problem, with 37% of adolescents meeting the clinical threshold according to parent report and 42% according to adolescent report. In contrast, prevalence rates for specific nighttime sleep problems ranged from 1.5% to 7.6%. Time spent in bed, bedtime resistance, ADHD inattentive symptoms, and Sluggish Cognitive Tempo (SCT) symptoms were significant in the final model predicting daytime sleepiness. Conclusion: Adolescents with ADHD commonly experience problems with daytime sleepiness that may significantly affect their functioning, but this may not be directly attributable to specific sleep problems.

Relations between caregiver-report of sleep and executive function problems in children with autism spectrum disorder and attention-deficit/hyperactivity disorder

BACKGROUND

Many children with autism spectrum disorder (ASD) experience comorbid symptoms of attention-deficit/hyperactivity disorder (ADHD). Additionally, children with ASD and ADHD often have sleep disturbances and deficits in executive functioning (EF). In typical development, sleep disturbances are causally linked to EF deficits and exacerbate ADHD-like symptoms.

AIM

The aim of this study was to determine whether caregiver-report sleep and EF difficulties predict ADHD symptoms in children with ASD.

METHODS

Caregiver-report of child sleep, EF, and ADHD symptom severity was collected for 101 children with ASD, 7-11 years of age. Hierarchical linear regressions tested the independent and interactive effects of sleep and EF in predicting ADHD symptoms.

RESULTS

Children with ASD were more likely to have symptoms of ADHD if they experienced both sleep and EF difficulties. Children with difficulties in working memory were particularly at risk for clinically significant symptoms of ADHD. Notably, however, sleep did not mediate or moderate the relation between working memory and ADHD symptoms in this sample, suggesting that these variables act through independent mechanisms to increase vulnerability for comorbidity.

CONCLUSIONS

These results have clinical significance as sleep and EF deficits may identify an ASD subgroup that is at increased risk for a comorbid ADHD diagnosis.

Positive emotional attention bias in young children with symptoms of ADHD

Children with attention-deficit/hyperactivity disorder (ADHD) often experience emotional dysregulation. Dysregulation can arise from heightened attention to emotional stimuli. Emotional attention biases are associated with a number of adverse socioemotional outcomes including reward sensitivity and externalizing behaviors. As reward sensitivity and externalizing behaviors are common in children with ADHD, the aim of the current study was to determine whether emotional attention biases are evident in young children with clinically significant ADHD symptoms. To test this, children with (n = 18) and without (n = 15) symptoms of ADHD were tested on a Dot Probe task. Provided recent evidence that emotional attention biases are attenuated by sleep, the task was performed before and after overnight sleep. Children with ADHD symptoms displayed positive, but not negative, attention biases at both time points, whereas typically developing children did not preferentially attend toward or away from positive or negative stimuli. Sleep did not alter attention biases in either group. Collectively, these results indicate that children with ADHD symptoms have stable, positive attention biases.

REM theta activity enhances inhibitory control in typically developing children but not children with ADHD symptoms

Sleep disturbances impair cognitive functioning in typically developing populations. Children with attention-deficit/hyperactivity disorder (ADHD), a disorder characterized by impaired inhibitory control and attention, commonly experience sleep disturbances. Whether inhibitory impairments are related to sleep deficits in children with ADHD is unknown. Children with ADHD (n = 18; M _age = 6.70 years) and typically developing controls (n = 15; M _age = 6.73 years) completed a Go/No-Go task to measure inhibitory control and sustained attention before and after polysomnography-monitored overnight sleep. Inhibitory control and sustained attention were improved following overnight sleep in typically developing children. Moreover, morning inhibitory control was positively correlated with rapid eye movement (REM) theta activity in this group. Although REM theta activity was greater in children with ADHD compared to typically developing children, it was functionally insignificant. Neither inhibitory control nor sustained attention was improved following overnight sleep in children with ADHD symptoms, and neither of these behaviors was associated with REM theta activity in this group. Taken together, these results indicate that elevated REM theta activity may be functionally related to ADHD symptomology, possibly reflecting delayed cortical maturation.

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.

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

OBJECTIVES

Much of what is currently known about the sleep functioning of children with attention-deficit/hyperactivity disorder (ADHD) is based on samples of children with ADHD combined type, and no study to date has examined the association between sluggish cognitive tempo (SCT) and sleep functioning in children diagnosed with ADHD. Accordingly, the objectives of this study were to (1) describe the sleep habits of children diagnosed with ADHD predominantly inattentive type (ADHD-I) and (2) examine whether comorbid internalizing, oppositional, and/or SCT symptoms are associated with poorer sleep functioning in children with ADHD-I. This study extends the current literature by using a large, clinical sample of children with ADHD-I to examine the association between SCT and other psychopathology symptoms with children's sleep functioning.

METHODS

Participants included 147 children (age: 6-11, 59% male, 55% White) diagnosed with ADHD-I using a semi-structured diagnostic interview. Parents completed measures assessing their child's sleep habits as well as comorbid anxiety, depression, oppositionality, and SCT symptoms.

RESULTS

Fourteen percent of children with ADHD-I obtain less sleep than recommended and 31% have a sleep onset latency of greater than 20 minutes. The few children taking medication for ADHD had a longer sleep onset latency than those without medication. Twenty-seven percent of parents indicated that it is "difficult" to get their child out of bed on school days and 41% of parents indicated that their child needs to catch-up on sleep on the weekend "at least a little". Regression analyses found anxiety and SCT sleepy/tired symptoms to be the most consistent dimensions of psychopathology associated with sleep functioning, with little support for depression or oppositionality being associated with sleep.

CONCLUSIONS

A sizeable minority of children with ADHD-I experience impaired sleep. In addition to SCT sleepy/tired symptoms, comorbid anxiety was most consistently associated with poorer sleep functioning in children with ADHD-I. SCT daydreaming and working memory symptoms were unassociated with sleep functioning, and the size of the effects between SCT sleepy/tired and sleep functioning indicates that these are not overlapping constructs. Longitudinal studies are needed to evaluate the interrelations of sleep problems and comorbid psychopathology symptoms and their impact on the daytime functioning of children with ADHD-I.