Reciprocal relations between dimensions of attention-deficit/hyperactivity and anxiety disorders from preschool age to adolescence: sex differences in a birth cohort sample.

BACKGROUND: Symptoms of anxiety and attention-deficit/hyperactivity disorder (ADHD) are prospectively related from childhood to adolescence. However, whether the two dimensions of ADHD-inattention and hyperactivity-impulsivity-are differentially related to anxiety and whether there are developmental and sex/gender differences in these relations are unknown. METHODS: Two birth cohorts of Norwegian children were assessed biennially from ages 4 to 16 (N = 1,077; 49% girls) with diagnostic parent interviews used to assess symptoms of anxiety and ADHD. Data were analyzed using a random intercept cross-lagged panel model, adjusting for all unobserved time-invariant confounding effects. RESULTS: In girls, increased inattention, but not hyperactivity-impulsivity, predicted increased anxiety 2 years later across all time-points and increased anxiety at ages 12 and 14 predicted increased inattention but not hyperactivity-impulsivity. In boys, increased hyperactivity-impulsivity at ages 6 and 8, but not increased inattention, predicted increased anxiety 2 years later, whereas increased anxiety did not predict increased inattention or hyperactivity-impulsivity. CONCLUSIONS: The two ADHD dimensions were differentially related to anxiety, and the relations were sex-specific. In girls, inattention may be involved in the development of anxiety throughout childhood and adolescence and anxiety may contribute to girls developing more inattention beginning in early adolescence. In boys, hyperactivity-impulsivity may be involved in the development of anxiety during the early school years. Effective treatment of inattention symptoms in girls may reduce anxiety risk at all time-points, while addressing anxiety may decrease inattention during adolescence. Similarly, treating hyperactivity-impulsivity may reduce anxiety risk in boys during late childhood (at ages 8-10).

Genetic and phenotypic evidence of the predictive validity of preschool parent reports of hyperactivity/impulsivity and inattention.

To determine the validity of parent reports (PRs) of ADHD in preschoolers, we assessed hyperactivity/impulsivity (HI) and inattention (IN) in 1114 twins with PRs at 1.5, 2.5, 4, 5, 14, 15, and 17 years, and teacher-reports at 6, 7, 9, 10, and 12. We examined if preschool PRs (1) predict high HI/IN trajectories, and (2) capture genetic contributions to HI/IN into adolescence. Group-based trajectory analyses identified three 6-17 years trajectories for both HI and IN, including small groups with high HI (N = 88, 10.4%, 77% boys) and IN (N = 158, 17.3%, 75% boys). Controlling for sex, each unit of HI PRs starting at 1.5 years and at 4 years for IN, increased more than 2-fold the risk of belonging to the high trajectory, with incremental contributions (Odds Ratios = 2.5-4.5) at subsequent ages. Quantitative genetic analyses showed that genetic contributions underlying preschool PRs accounted for up to a quarter and a third of the heritability of later HI and IN, respectively. Genes underlying 1.5-year HI and 4-year IN contributed to 6 of 8 later HI and IN time-points and largely explained the corresponding phenotypic correlations. Results provide phenotypic and genetic evidence that preschool parent reports of HI and IN are valid means to predict developmental risk of ADHD.

Shared Genetic Factors Contributing to the Overlap between Attention-Deficit/Hyperactivity Disorder Symptoms and Overweight/Obesity in Swedish Adolescent Girls and Boys.

Attention-deficit/hyperactivity disorder (ADHD) and obesity are positively associated, with increasing evidence that they share genetic risk factors. Our aim was to examine whether these findings apply to both types of ADHD symptoms for female and male adolescents. We used data from 791 girl and 735 boy twins ages 16-17 years to examine sex-specific phenotypic correlations between the presence of ADHD symptoms and overweight/obese status. For correlations exceeding .20, we then fit bivariate twin models to estimate the genetic and environmental correlations between the presence of ADHD symptoms and overweight/obese status. ADHD symptoms and height/weight were parent- and self-reported, respectively. Phenotypic correlations were .30 (girls) and .08 (boys) for inattention and overweight/obese status and .23 (girls) and .14 (boys) for hyperactivity/impulsivity and overweight/obese status. In girls, both types of ADHD symptoms and overweight/obese status were highly heritable, with unique environmental effects comprising the remaining variance. Furthermore, shared genetic effects explained most of the phenotypic correlations in girls. Results suggest that the positive association of both types of ADHD symptoms with obesity may be stronger in girls than boys. Further, in girls, these associations may stem primarily from shared genetic factors.

Shortened Infant Telomere Length Is Associated with Attention Deficit/Hyperactivity Disorder Symptoms in Children at Age Two Years: A Birth Cohort Study.

Environmental factors can accelerate telomere length (TL) attrition. Shortened TL is linked to attention deficit/hyperactivity disorder (ADHD) symptoms in school-aged children. The onset of ADHD occurs as early as preschool-age, but the TL-ADHD association in younger children is unknown. We investigated associations between infant TL and ADHD symptoms in children and assessed environmental factors as potential confounders and/or mediators of this association. Relative TL was measured by quantitative polymerase chain reaction in cord and 12-month blood in the birth cohort study, the Barwon Infant Study. Early life environmental factors collected antenatally to two years were used to measure confounding. ADHD symptoms at age two years were evaluated by the Child Behavior Checklist Attention Problems (AP) and the Attention Deficit/Hyperactivity Problems (ADHP). Associations between early life environmental factors on TL or ADHD symptoms were assessed using multivariable regression models adjusted for relevant factors. Telomere length at 12 months (TL12), but not at birth, was inversely associated with AP (ß = -0.56; 95% CI (-1.13, 0.006); p = 0.05) and ADHP (ß = -0.66; 95% CI (-1.11, -0.21); p = 0.004). Infant secondhand smoke exposure at one month was independently associated with shorter TL12 and also higher ADHD symptoms. Further work is needed to elucidate the mechanisms that influence TL attrition and early neurodevelopment.

Genetic and environmental contribution to the overlap between ADHD and ASD trait dimensions in young adults: a twin study.

BACKGROUND: Traits of attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) are strongly associated in children and adolescents, largely due to genetic factors. Less is known about the phenotypic and aetiological overlap between ADHD and ASD traits in adults. METHODS: We studied 6866 individuals aged 20-28 years from the Swedish Study of Young Adult Twins. Inattention (IA) and hyperactivity/impulsivity (HI) were assessed using the WHO Adult ADHD Self-Report Scale-V1.1. Repetitive and restricted behaviours (RRB) and social interaction and communication (SIC) were assessed using the Autism-Tics, ADHD, and other Comorbidities inventory. We used structural equation modelling to decompose covariance between these ADHD and ASD trait dimensions into genetic and shared/non-shared environmental components. RESULTS: At the phenotypic level, IA was similarly correlated with RRB (r = 0.33; 95% Confidence Interval (CI) 0.31-0.36) and with SIC (r = 0.32; 95% CI 0.29-0.34), whereas HI was more strongly associated with RRB (r = 0.38; 95% CI 0.35-0.40) than with SIC (r = 0.24; 95% CI 0.21-0.26). Genetic and non-shared environmental effects accounted for similar proportions of the phenotypic correlations, whereas shared environmental effects were of minimal importance. The highest genetic correlation was between HI and RRB (r = 0.56; 95% 0.46-0.65), and the lowest was between HI and SIC (r = 0.33; 95% CI 0.23-0.43). CONCLUSIONS: We found evidence for dimension-specific phenotypic and aetiological overlap between ADHD and ASD traits in adults. Future studies investigating mechanisms underlying comorbidity between ADHD and ASD may benefit from exploring several symptom-dimensions, rather than considering only broad diagnostic categories.

The role of birth weight on the causal pathway to child and adolescent ADHD symptomatology: a population-based twin differences longitudinal design.

BACKGROUND: Available evidence points towards lower birth weight as a risk factor for the development of attention deficit/hyperactivity disorder (ADHD) symptoms. We probed the causal nature of this putative effect of birth weight on ADHD symptoms using the twin differences design, which accounts for genetic and shared environmental confounds. METHOD: In a large population-based twin sample - 3,499 monozygotic (MZ) and 6,698 dizygotic (DZ) pairs - parents, teachers or twins rated the twins' ADHD symptoms at nine assessment waves (2-16 years). We implemented the twin differences design, which completely accounts for shared environmental and genetic confounding in MZ twins. We tested whether: (a) the lighter-born twins had elevated ADHD symptoms compared to the heavier-born twins, by regressing within-pair differences of ADHD symptoms on within-pair differences of birth weight among MZ twins; (b) the effect of birth weight on ADHD was moderated by gender, gestational age and low birth weight; (c) this effect changed with age at ADHD assessment using adapted latent growth curve models; and (d) results differed for inattention and hyperactivity/impulsivity. RESULTS: Birth weight significantly predicted ADHD symptoms from early childhood to late adolescence. The lighter-born twin had more ADHD symptoms than the heavier-born cotwin among MZ twins across assessment waves and raters. No moderation effect was detected. The magnitude of the effect of birth weight decreased significantly across time for hyperactivity/impulsivity, but the decrease failed to reach significance for inattention. Estimates for inattention were significantly larger than for hyperactivity/impulsivity at each time point, implying stronger effect of birth weight on inattention symptoms. CONCLUSIONS: Our findings provide stringent evidence for environmental effect of lower birth weight on the causal pathway to elevated ADHD symptoms. Effect of birth weight persists across a 14-year period from childhood into late adolescence, in particular for inattention symptoms.

Attention Deficit Hyperactivity Disorder (ADHD): Controversy, Developmental Mechanisms, and Multiple Levels of Analysis.

Controversy abounds regarding the symptom dimensions of attention problems, impulsivity, and hyperactivity, developmentally extreme and impairing levels of which compose the diagnostic category of attention deficit hyperactivity disorder (ADHD). I highlight causal factors, underlying mechanisms, developmental trajectories, and female manifestations of ADHD, integrating the psychobiological underpinnings of this syndrome with contextual factors related to its clinical presentation, impairments, and soaring increases in diagnosed prevalence. Indeed, despite strong heritability, ADHD is expressed via transactional patterns of influence linked to family-, school-, peer-, neighborhood-, and policy-related factors. Moreover, intervention strategies must take into account both pharmacologic and behavioral modalities if the goal is to enhance competencies, rather than symptom reduction per se. A comprehensive understanding of ADHD mandates multiple levels of analysis-spanning genes, neurotransmission, brain pathways, individual skill levels, family socialization, peer relationships, and educational and cultural forces-which must be integrated and synthesized to surpass reductionist accounts, reduce stigma, and maximize the impact of prevention- and intervention-related efforts.

Prevalence of attention-deficit/hyperactivity disorder symptoms and their associations with sleep schedules and sleep-related problems among preschoolers in mainland China.

BACKGROUND: Attention-deficit/hyperactivity disorder (ADHD) among children is an increasing public health concern. The identification of behavioral risk factors, including sleep quality, has important public health implications for prioritizing behavioral intervention strategies for ADHD. Herein, this study aimed to investigate the prevalence of high levels of ADHD symptoms and to explore the association between sleep schedules, sleep-related problems and ADHD symptoms among preschoolers aged 3 to 6 years in mainland China. METHODS: A cross-sectional study was conducted, comprising a large sample of 15,291 preschoolers in Ma'anshan city of Anhui Province in China. ADHD symptoms were assessed by the 10-item Chinese version of the Conners Abbreviated Symptom Questionnaire (C-ASQ). Sleep-related variables included caregivers' responses to specific questions addressing children's daytime and nighttime sleep schedules, as well as sleep-related behaviors. Data on other factors were also collected, such as socio-demographic characteristics, TV viewing duration on weekdays and weekends, and outdoor activities. Logistic regression models were used to analyze the relationships between sleep schedules, sleep-related problems and ADHD symptoms. RESULTS: Approximately 8.6% of the total sample of preschoolers had high levels of ADHD symptoms, with boys having higher levels than girls (9.9% vs. 7.2%). In the logistic regression analysis, after adjusting for TV viewing duration, outdoor activities, and socio-demographic characteristics, delayed bedtime was significantly associated with a risk of high levels of ADHD symptoms, with odds ratios (OR) of 2.50 [95% confidence interval (CI): 2.09 ~ 3.00] and 2.04 (95% CI: 1.72 ~ 2.42) for weekdays and weekends, respectively. Longer time falling asleep (≥ 31 min) (OR = 1.76, 95% CI: 1.47 ~ 2.11), no naps (OR = 1.57, 95% CI: 1.34 ~ 1.84) and frequent sleep-related problems (OR = 4.57, 95% CI: 3.86 ~ 5.41) were also significantly associated with an increased risk of high levels of ADHD symptoms, while longer sleep duration (> 8.5 h) was associated with a decreased risk of high levels of ADHD symptoms (OR = 0.76, 95% CI: 0.67~ 0.87). CONCLUSIONS: ADHD symptoms are prevalent in preschoolers in Ma'anshan region, China. Undesirable sleep schedules and sleep-related problems among preschoolers confer a risk of ADHD symptoms, highlighting the finding that beneficial and regular sleep habits potentially attenuate ADHD symptoms among preschoolers.

Comorbid psychiatric conditions as mediators to predict later social adjustment in youths with autism spectrum disorder.

BACKGROUND: Individuals with autism spectrum disorder (ASD) experience long-term social impairment and their comorbid psychiatric conditions negatively impact adaptive functioning. The aims of the study are to investigate whether comorbid psychopathologies, such as anxiety/depression, inattention, hyperactivity/impulsivity, and oppositional behaviors, mediated the link between autistic symptoms and social maladjustment. METHOD: One hundred and twenty-four youths diagnosed with a clinical diagnosis of DSM-IV ASD (mean age, 10.6 ± 3.3 years) participated in this longitudinal study. They were assessed using semistructured diagnostic interviews on ASD and other psychiatric conditions at recruitment. Follow-up interviews took place approximately 3 years later (37.59 ± 15 months) while the parents reported to the Social Adjustment Inventory for Children and Adolescents on their children's social adjustment. Mediation models were used to examine the mediating effect of comorbid psychopathologies on social adjustment. RESULTS: Youths with ASD had worse school, peer, and home functions than controls at follow-up assessment. In general, comorbid psychiatric conditions mediated the link between autistic symptoms and different domains of social adjustment, independent of age, sex, and full-scale IQ. Additionally, we found specific mediating effects of anxiety/depression and inattention on school functions; anxiety/depression on peer relationships; and oppositional behaviors on home behaviors. CONCLUSION: Early comorbid psychopathologies may further impair later social adjustment in youths with ASD and an early identification and intervention of these comorbid conditions are suggested.

The Prospective Links Between Hyperactive/Impulsive, Inattentive, and Oppositional-Defiant Behaviors in Childhood and Antisocial Behavior in Adolescence: The Moderating Influence of Gender and the Parent-Child Relationship Quality.

We prospectively investigated the effect of child hyperactive/impulsive, inattentive, and oppositional/defiant behaviors on the development of youth antisocial behaviors, and the moderating influence of gender and the parent-child relationship quality in a normative sample. Participants (N = 673, 50 % girls) were assessed at 10 years of age (parent reports) and at age 15 (parent and adolescent reports). Using latent change models, we found that initial levels of, as well as increases in, hyperactivity/impulsivity and oppositional behaviors and initial levels of inattention behaviors predicted youth antisocial behaviors. The increase in oppositional behaviors was predictive of youth antisocial behaviors in girls only. Child hyperactive/impulsive behaviors predicted youth antisocial behaviors only in children for whom the quality of the parent-child relationship deteriorated from childhood to adolescence. Thus, both initial levels of and increases in disruptive behaviors as well as gender are important for understanding the development of antisocial behaviors in adolescence. We received partial support for the hypothesized, moderating role of a high-quality parent-child relationship.

Testing for the mediating role of endophenotypes using molecular genetic data in a twin study of ADHD traits.

Family and twin studies have identified endophenotypes that capture familial and genetic risk in attention-deficit/hyperactivity disorder (ADHD), but it remains unclear if they lie on the causal pathway. Here, we illustrate a stepwise approach to identifying intermediate phenotypes. First, we use previous quantitative genetic findings to delineate the expected pattern of genetically correlated phenotypes. Second, we identify overlapping genetic associations with ADHD-related quantitative traits. Finally, we test for the mediating role of associated endophenotypes. We applied this approach to a sample of 1,312 twins aged 7-10. Based on previous twin model-fitting analyses, we selected hyperactivity-impulsivity, inattention, reading difficulties (RD), reaction time variability (RTV) and commission errors (CE), and tested for association with selected ADHD risk alleles. For nominally significant associations with both a symptom and a cognitive variable, matching the expected pattern based on previous genetic correlations, we performed mediation analysis to distinguish pleiotropic from mediating effects. The strongest association was observed for the rs7984966 SNP in the serotonin receptor gene (HTR2A), and RTV (P = 0.007; unadjusted for multiple testing). Mediation analysis suggested that CE (38%) and RTV (44%) substantially mediated the association between inattention and the T-allele of SNP rs3785157 in the norepinephrine transporter gene (SLC6A2) and the T-allele of SNP rs7984966 in HTR2A, respectively. The SNPs tag risk-haplotypes but are not thought to be functionally significant. While these exploratory findings are preliminary, requiring replication, this study demonstrates the value of this approach that can be adapted to the investigation of multiple genetic markers and polygenic risk scores. © 2016 The Authors. American Journal of Medical Genetics Part B: Neuropsychiatric Genetics Published by Wiley Periodicals, Inc.

Phenotypic and genetic associations between reading comprehension, decoding skills, and ADHD dimensions: evidence from two population-based studies.

BACKGROUND: The phenotypic and genetic associations between decoding skills and ADHD dimensions have been documented but less is known about the association with reading comprehension. The aim of the study is to document the phenotypic and genetic associations between reading comprehension and ADHD dimensions of inattention and hyperactivity/impulsivity in early schooling and compare them to those with decoding skills. METHODS: Data were collected in two population-based samples of twins (Quebec Newborn Twin Study - QNTS) and singletons (Quebec Longitudinal Study of Child Development - QLSCD) totaling ≈ 2300 children. Reading was assessed with normed measures in second or third grade. Teachers assessed ADHD dimensions in kindergarten and first grade. RESULTS: Both decoding and reading comprehension were correlated with ADHD dimensions in a similar way: associations with inattention remained after controlling for the other ADHD dimension, behavior disorder symptoms and nonverbal abilities, whereas associations with hyperactivity/impulsivity did not. Genetic modeling showed that decoding and comprehension largely shared the same genetic etiology at this age and that their associations with inattention were mostly explained by shared genetic influences. CONCLUSION: Both reading comprehension and decoding are uniquely associated with inattention through a shared genetic etiology.

White matter microstructure and developmental improvement of hyperactive/impulsive symptoms in attention-deficit/hyperactivity disorder.

BACKGROUND: A developmental improvement of symptoms in attention-deficit/hyperactivity disorder (ADHD) is frequently reported, but the underlying neurobiological substrate has not been identified. The aim of this study was to determine whether white matter microstructure is related to developmental improvement of ADHD symptoms. METHODS: A cross-sectional magnetic resonance imaging (MRI) analysis was embedded in a prospective follow-up of an adolescent cohort of ADHD and control subjects (NeuroIMAGE). Mean age at baseline was 11.9 years, mean interval of follow-up was 5.9 years. About 75.3% of the original cohort was retained successfully. Data of 101 participants with ADHD combined type at baseline and 40 healthy controls were analysed. ADHD symptoms were measured with semistructured, investigator-based interviews and Conners' questionnaires, on the basis of DSM-IV criteria. Fractional anisotropy (FA) and mean diffusivity (MD) indices of white matter microstructure were measured using whole brain diffusion tensor imaging at follow-up only. In a dimensional analysis FA and MD were related to change in ADHD symptoms. To link this analysis to DSM-IV diagnoses, a post hoc categorical group analysis was conducted comparing participants with persistent (n = 59) versus remittent (n = 42) ADHD and controls. RESULTS: Over time, participants with ADHD showed improvement mainly in hyperactive/impulsive symptoms. This improvement was associated with lower FA and higher MD values in the left corticospinal tract at follow-up. Findings of the dimensional and the categorical analysis strongly converged. Changes in inattentive symptoms over time were minimal and not related to white matter microstructure. CONCLUSIONS: The corticospinal tract is important in the control of voluntary movements, suggesting the importance of the motor system in the persistence of hyperactive/impulsive symptoms.

Assessing sensory processing problems in children with and without attention deficit hyperactivity disorder.

AIMS: This exploratory study investigated whether children with attention-deficit/hyperactivity disorder (ADHD) are at greater risk than children without ADHD for problems with sensory processing and if certain sensory systems are more closely associated with the core symptoms of ADHD, specifically inattention and hyperactivity/impulsivity. METHODS: The sample included 20 children with ADHD and 27 children without ADHD, ages 5 to 10 years. Assessments included the Sensory Processing Measure-Home Form and the Conners 3rd edition-Parent Short Form. RESULTS: After controlling for age, children with ADHD exhibited more sensory processing problems on all scales of the Sensory Processing Measure with small to medium effect sizes observed (η(2) = .27 to .61). For children with ADHD, the Social Participation (r = .50) and Planning and Ideas (r = .73) subtests of the Sensory Processing Measure were significantly associated with hyperactivity/impulsivity, but not with inattention on the subtests of the Conners Parent Short Form. CONCLUSION: The results suggest the importance of assessing sensory processing issues in children with ADHD to guide in the intervention process.

Can an active lifestyle reduce the risk of obesity in adulthood among adolescents with Attention-Deficit/Hyperactivity Disorder symptoms? An ambispective cohort study.

Various studies have associated Attention-Deficit/Hyperactivity Disorder (ADHD) with obesity, but the role of physical activity in this connection is uncertain. This study examined whether adopting an active lifestyle can mitigate the link between adolescent ADHD and the risk of adult obesity. Longitudinal data from the Add Health Study (Waves I, III, and V) were used. Participants self-reported ADHD symptoms (hyperactivity/impulsivity, inattention, combined) during Wave III and self-assessed their recent moderate-to-vigorous physical activity. An "active lifestyle" required meeting activity criteria in both adolescence (Wave I) and adulthood (Wave III-V). Of 2609 participants, 1.42 % exhibited combined ADHD symptoms. A non-linear relationship was observed between inattentive/hyperactive scores and body mass index (BMI) and waist circumference (WC). Individuals with ≥ 6 hyperactivity/impulsivity symptoms had higher BMI (1.29 kg/m²) and WC (1.27 cm) at adulthood. Logistic regressions indicate that, compared to individuals without ADHD maintaining an active lifestyle, both inactive participants with and without ADHD show an elevated risk of obesity (odds ratio [OR]=1.56 to 2.63) and abdominal obesity in adulthood (OR = 1.51 to 2.50). Mediation analysis models further confirm these findings, suggesting that physical activity may explain this association. Though exact mechanisms warrant further exploration, adopting an active lifestyle offers promise for reducing obesity risk among individuals with ADHD symptoms.

Disentangling the relationships between motor control and cognitive control in young children with symptoms of ADHD.

Children with ADHD experience difficulties with motor and cognitive control. However, the relationships between these symptoms are poorly understood. As a step toward improving treatment, this study investigated associations between specific aspects of motor control and cognitive control in children with varying levels of hyperactive-impulsive symptoms. A heterogeneous sample of 255 children of 4 to 10 years of age (median = 6.50, MAD = 1.36) completed a battery of tests probing motor generation, visuomotor fluency, visuomotor flexibility, cognitive inhibition, verbal and visuospatial working memory, and cognitive flexibility. Their caregivers were interviewed regarding their hyperactive-impulsive symptoms. 25.9% of the main sample met diagnostic criteria for ADHD. Multiple linear regression analysis was used to determine whether specific aspects of motor control were associated with specific aspects of cognitive control, and whether any associations were moderated by hyperactive-impulsive symptoms. Additionally, cognitive modeling (the drift diffusion model approximated with EZ-DM) was used to understand performance on a cognitive inhibition task. Visuomotor fluency was significantly associated with cognitive inhibition. Visuomotor flexibility was significantly associated with cognitive flexibility. There were no significant moderation effects. Cognitive modeling was inconclusive. In conclusion, the ability to fluently perform visually guided continuous movement is linked with the ability to inhibit the effects of distracting information. The ability to spontaneously use visual information to flexibly alter motor responses is related to the ability to cognitively shift from one frame of mind to another. These relationships appear to be quantitatively and qualitatively similar across the childhood hyperactive-impulsive continuum as rated by parents.

Efficacy and tolerability of psychostimulants for symptoms of attention-deficit hyperactivity disorder in preschool children: A systematic review and meta-analysis.

BACKGROUND: There was no previous meta-analysis investigating the efficacy/tolerability of psychostimulants for symptoms of attention-deficit hyperactivity disorder (ADHD) in preschool children. METHODS: Databases including PubMed, the Cochrane Library, EMBASE, ScienceDirect, and ClinicalTrials.gov were searched from inception to March 2022 for randomized controlled trials (RCTs) on therapeutic efficacy of psychostimulants against ADHD symptoms in preschool children (age ≤6 years) compared with placebos. Primary outcomes were (a) changes in ADHD symptoms evaluated by validated rating scales from parents'/teacher's observation, or (b) post-intervention improvements in neuropsychological performance. Secondary outcomes were risks of adverse events. RESULTS: Meta-analysis of nine eligible trials including 544 preschool children (mean age=4.86 years, female=11.98%, median treatment duration=4.33 weeks) supported the efficacy of psychostimulants against global symptoms from observations of parents (Hedges' g=0.6152, p<0.0001) and teachers (Hedges' g=0.6563, p=0.0039). Efficacy of psychostimulants was also noted against symptoms of inattention and hyperactivity/impulsivity, especially the latter (i.e., main symptoms in preschool children). Moreover, male gender, older age, and longer treatment duration were associated with better efficacy. Regarding adverse events, only the risk of poor appetite was higher in the psychostimulant group (odds ratio [OR]=2.39). However, the qualities of evidence were low to very low, indicating potential discrepancy between the true and estimated effect. CONCLUSIONS: Our results showed that psychostimulants might be beneficial for preschool children with ADHD, especially hyperactivity/impulsivity from teachers' observation, with tolerable side effects. Nevertheless, the true magnitude of the effect needs to be confirmed with more research due to low to very low certainty of the evidence.

Genetic background to attention deficit and hyperactivity disorder and attention deficit and hyperactivity disorder symptoms at the age of 5 years: the role of sleep duration.

STUDY OBJECTIVES: We studied the associations between polygenic risk score (PRS) for attention deficit and hyperactivity disorder (ADHD) and (1) ADHD symptoms in 5-year-old children, (2) sleep duration throughout childhood, and (3) the interaction between PRS for ADHD and short sleep duration relative to ADHD symptoms at 5 years. METHODS: This study is based on the population-based CHILD-SLEEP birth cohort (N = 1420 children). PRS was used to quantitate the genetic risk for ADHD. Parent-reported ADHD symptoms at 5 years were obtained from 714 children, using the Strengths and Difficulties Questionnaire (SDQ) and the Five-to-Fifteen (FTF). Our primary outcomes were SDQ-hyperactivity and FTF-ADHD total scores. Parent-reported sleep duration was measured at 3, 8, 18, 24 months, and 5 years in the whole sample and actigraphy-based sleep duration at 2 and 24 months in a subsample. RESULTS: PRS for ADHD associated with SDQ-hyperactivity (ß = 0.214, p = .012) and FTF-ADHD total (ß = 0.639, p = .011), and FTF-inattention and hyperactivity subscale scores (ß = 0.315, p = .017 and ß = 0.324, p = .030), but not with sleep duration at any time point. Significant interactions were found between high PRS for ADHD and parent-reported short sleep throughout childhood in FTF-ADHD total score (F = 4.28, p = .039) and FTF-inattention subscale (F = 4.66, p = .031). We did not find any significant interaction between high PRS for ADHD and actigraphy-based short sleep. CONCLUSIONS: Parent-reported short sleep moderates the association between genetic risk of ADHD and ADHD symptoms in early childhood in the general population, so that children with short sleep, in combination with high genetic risk for ADHD, could be at highest risk for ADHD symptoms.

The Effect of Meditation-Based Mind-Body Interventions on Symptoms and Executive Function in People With ADHD: A Meta-Analysis of Randomized Controlled Trials.

OBJECTIVE: This study aims to perform a systematic review and meta-analysis of the effect of MBIs (Mindfulness, Tai Chi, Yoga, and Qigong) on symptoms and executive function (EF) in ADHD. METHOD: PubMed, Web of Science, the Cochrane Library, PsycINFO, CINAHL, Embase, and CNKI databases were searched to collect randomized controlled trials (RCTs) on the effects of MBIs on symptoms and EF in ADHD. Data extraction and methodological quality evaluation were conducted by two researchers, and a meta-analysis was conducted by Stata SE. RESULTS: The pooled meta-analyses of MBIs revealed a positive and small effect on inattention (g = -0.26), hyperactivity/impulsivity (g = -0.19), and EF (g = -0.35). CONCLUSION: Results suggest that MBIs have a significant improvement relative to the control condition. Although some results show that symptoms are affected by age, interventions, and total time of moderators, while EF is not affected by age and measurement, it needs to be supported by more research evidence. (J. of Att. Dis. XXXX; XX(X) XX-XX).

Predictors of Problematic Video Gaming in Elementary School Boys with ADHD.

The aim of the study was to expand the current knowledge base on problematic video gaming and ADHD with four questions: (1) Are there differences in the length of video gaming between boys with ADHD and typically developing boys? (2) Are there differences in problematic video gaming between boys with ADHD and typically developing boys? (3) What are the predictors of problematic video gaming? (4) Does problematic video gaming affect academic performance while controlling for the effect of inattention and hyperactivity/impulsivity symptoms? Symptoms of inattention, hyperactivity/impulsivity scale (SNAP IV), the Problematic Video Game Scale, and the Video Game Patterns Questionnaire were administered to 127 parents of elementary school boys in Croatia, 57 of whom were parents of boys with a clinical ADHD diagnosis and 70 of whom were parents of typically developing boys. The results show that there are no differences in length of play and problematic video gaming between ADHD and typically developing boys. A hierarchical regression analysis showed that age, inattention symptoms, and length of play are predictors of problematic video gaming. Inattention symptoms and age are significant predictors of academic achievement whereas it seems that hyperactivity and impulsivity symptoms are not predictors of problematic video gaming and academic achievement in boys.