What have we learnt about the causes of ADHD?

Gut dysbiosis as a driver of neuroinflammation in attention-deficit/hyperactivity disorder: A review of current evidence

There is mounting evidence for the involvement of the immune system, neuroinflammation and disturbed gut microbiota, or dysbiosis, in attention-deficit/hyperactivity disorder (ADHD). Gut dysbiosis is strongly implicated in many physical, autoimmune, neurological, and neuropsychiatric conditions, however knowledge of its particular pathogenic role in ADHD is sparse. As such, this narrative review examines and synthesizes the available evidence related to inflammation, dysbiosis, and neural processes in ADHD. Minimal differences in microbiota diversity measures between cases and controls were found, however many relative abundance differences were observed at all classification levels (phylum to strain). Compositional differences of taxa important to key gut-brain axis pathways, in particular Bacteroides species and Faecalibacterium, may contribute to inflammation, brain functioning differences, and symptoms, in ADHD. We have identified one possible model of ADHD etiopathogenesis involving systemic inflammation, an impaired blood-brain barrier, and neural disturbances as downstream consequences of gut dysbiosis. Nevertheless, studies conducted to date have varied degrees of methodological rigour and involve diverse participant characteristics and analytical techniques, highlighting a need for additional research.

Can Vıtamın D Reduce the Need for SSRI by Modulatıng Serotonın Synthesıs?: A Revıew of Recent Lıterature

PURPOSE OF REVIEW

This study aims to analyze the effects of vitamin D on serotonin synthesis, release, and function in the brain, and to explore its relationship with various psychiatric disorders.

RECENT FINDINGS

The hormone calcitriol plays a vital role in regulating a multitude of biological processes within the human body. Its deficiency can lead to significant adverse effects on overall health and well-being, including physical and psychological consequences. Evidence indicates that vitamin D may exert influences through receptors in the brain, modulating serotonin production and influencing emotional and cognitive processes. Recent studies propose that elevated serum vitamin D may enhance mood and alleviate depressive states. The impact of vitamin D on cognitive function and behavior remains an area of ongoing investigation. This literature review analyses the available evidence on how vitamin D intake impacts the severity of illness and medication requirements in diverse psychiatric disorders. A review of the literature suggests that there may be a correlation between vitamin D and serotonin, which could potentially contribute to more favorable outcomes in the context of illness. Vitamin D may increase the amount of serotonin in the synaptic gap, which is the intended use of selective serotonin reuptake inhibitors (SSRIs), with its effect on the increase in serotonin release. According to reports, vitamin D supplementation in conjunction with SSRI group medication provides an additive effect for the management of psychiatric disorders.

Connections Between the Middle Frontal Gyrus and the Dorsoventral Attention Network Are Associated With the Development of Attentional Symptoms

BACKGROUND

The right middle frontal gyrus (MFG) has been proposed as a convergence site for the dorsal attention network (DAN) and ventral attention network (VAN), regulating both networks and enabling flexible modulation of attention. However, it is unclear whether the connections between the right MFG and these networks can predict changes in attention-deficit/hyperactivity disorder (ADHD) symptoms.

METHODS

This study used data from the Children School Functions and Brain Development project (N = 713, 56.2% boys). Resting-state functional magnetic resonance imaging was employed to analyze the connections of the right MFG with the DAN/VAN; connectome-based predictive modeling was applied for longitudinal prediction, and ADHD polygenic risk scores were used for genetic analysis.

RESULTS

ADHD symptoms were associated with the connections between the right MFG and DAN subregion, including the frontal eye field, as well as the VAN subregions, namely the inferior parietal lobule and inferior frontal gyrus. Furthermore, these connections of the right MFG with the frontal eye field, the inferior parietal lobule, and the inferior frontal gyrus could significantly predict changes in ADHD symptoms over 1 year and mediate the prediction of ADHD symptom changes by polygenic risk scores for ADHD. Finally, the validation samples confirmed that the functional connectivity between the right MFG and the frontal eye field/inferior parietal lobule in patients with ADHD was significantly weaker than that in typically developing control participants, and this difference disappeared after medication.

CONCLUSIONS

The connection of the right MFG with the DAN and VAN can serve as a predictive indicator for changes in ADHD symptoms over the following year, while also mediating the prediction of ADHD symptom changes by a polygenic risk score for ADHD. These findings hold promise as potential biomarkers for early identification of children who are at risk of developing ADHD.

Regional educational environment and its association with attention-deficit/hyperactivity disorder diagnosis in South Korea (2013-2019)

PURPOSE

The educational environment's characteristics (e.g., class size) may affect attention-deficit/hyperactivity disorder (ADHD) diagnosis. We investigated changes in the number of individuals newly diagnosed with ADHD according to regional differences in educational conditions in South Korea.

METHODS

With increasing class sizes, we hypothesized that teachers may experience more difficulty managing their students with hyperactive/impulsive symptoms or become less sensitive in detecting students with inattentive symptoms, causing a change in referrals for ADHD assessment. The annual number of ADHD diagnoses for each region was obtained from the National Health Insurance Service. The effects of educational conditions (i.e., number of students per teaching staff member, students per class, and private classes per 10,000 population) on newly diagnosed ADHD cases were analyzed separately for young people and adults.

RESULTS

In the final adjusted quasi-Poisson regression model without interactions, we observed a negative correlation between both the number of students per class and the number of private classes per 10,000 population and ADHD diagnosis in young people and adults. Further analysis revealed that a greater number of private classes in a region was associated with a decrease in ADHD diagnosis, especially in the lowest educated districts. By contrast, a higher number of students per class in kindergarten was associated with an increase in ADHD diagnosis, especially in the highest educated districts.

CONCLUSION

The educational environment's regional characteristics may affect ADHD detection and diagnosis. This association's direction may vary according to the regional educational level. A different association may also be observed in younger children.

White matter microstructural integrity mediates associations between prenatal endocrine-disrupting chemicals exposure and intelligence in adolescents

Per- and polyfluoroalkyl substances (PFAS) and phthalic acid esters (PAEs) are well-known endocrine-disrupting chemicals (EDCs) that potentially affect child neurodevelopment. We aimed to investigate the effects of prenatal exposure to PFAS and PAEs on macro- and micro-structural brain development and intelligence in adolescents using multimodal neuroimaging techniques. We employed structural magnetic resonance imaging (MRI) and various diffusion MRI techniques, including diffusion tensor imaging (DTI), diffusion kurtosis imaging (DKI), and neurite orientation dispersion and density imaging (NODDI), to assess the gray-matter macrostructure and white-matter microstructural integrity and complexity. Participants were drawn from a birth cohort of 52 mother-child pairs in central Taiwan recruited in 2001, and the adolescent intelligence quotient (IQ) scores were assessed using the Wechsler Intelligence Scale. Nine PFAS concentrations of cord blood and maternal serum samples were obtained from the children's mothers during the third trimester of pregnancy (27-40 weeks) using a liquid chromatography system coupled to a triple-quadrupole mass spectrometer, while maternal urinary phthalates were used to evaluate PAEs exposure. Our results showed significant associations between prenatal exposure to PFAS and phthalates with changes in specific fronto-parietal regions of the adolescent male brain, including reduced cortical thickness in the inferior frontal gyrus and right superior parietal cortex, which are involved in language, memory, and executive function. A dose-response association was observed, with higher levels of PFAS and PAE exposure modulating altered white-matter fiber integrity in the superior cerebellar peduncle and inferior cerebellar peduncle of the male and female adolescent brains. In addition, higher levels of prenatal exposure to EDCs were associated with lower IQ scores in adolescents. Mediation analyses further revealed that white-matter microstructure of inter-hemispheric and cerebellar fibers mediated the association between prenatal EDC exposure and adolescent IQ scores in female adolescents. Our multimodal human neuroimaging findings suggest that prenatal exposure to EDCs may have long-lasting effects on neuroanatomical development, neural fiber connectivity, and intelligence in adolescents, and highlight the importance of using advanced diffusion imaging techniques, including DKI and NODDI, to detect neurodevelopmental changes and their brain-behavioral consequences with the risks associated with these environmental exposures.

Increasing specificity in ADHD genetic association studies during childhood: use of the oxytocin-vasopressin pathway in attentional processes suggests specific mechanism for endophenotypes in the 2004 Pelotas birth (Brazil) cohort

Attentional executive functions, representing a set of self-regulatory cognitive skills, can be a potential Attention-Deficit/Hyperactivity Disorder (ADHD) endophenotype useful for exploring the huge heterogeneity associated to the disorder. Specific biological pathways like the oxytocin-vasopressin pathway (OT-AVP) can unreel ADHD polygenicity. Here, we test the association between genome-wide ADHD polygenic score (PGS) (ADHD-PGS) and both ADHD symptoms and attentional executive functions in the participants of the 2004 Pelotas (Brazil) birth cohort study (N = 4231). We also investigated whether the OT-AVP genomic pathway (OT/AVPADHD-PGS) is involved in the etiology of ADHD and whether it influences the specificity of attentional functions. ADHD symptoms were assessed through the Strength and Difficulties Questionnaire (SDQ) and the attentional executive functions were evaluated by the Test-of-Everyday-Attention-for-Children (TEA-Ch) at 11 years follow-up. The ADHD-PGS and OT/AVPADHD-PGS were constructed based on the most recent ADHD GWAS meta-analytic statistics. The OT/AVPADHD-PGS included only functional relevant genes for the pathway using KEGG repository. ADHD-PGS was associated with ADHD symptoms and attentional control/switching domain. OT/AVPADHD-PGS showed an enrichment for selective attention domain [number of targets (β = - 0.09, 95% CI = - 0.17; - 0.02, competitive-P = 0.025); attention score (β = 0.11, 95% CI = 0.001; 0.23, competitive-P = 0.050), and in attentional control/switching domain [verbal processing speed (β = 0.27, 95% CI = 0.05; 0.50, competitive-P = 0.041); attentional control (β = 0.42, 95% CI = 0.12; 0.73, competitive-P = 0.033). Our results show a specific role of the OT/AVP pathway in attentional executive functions and suggest that increasing both phenotypic and genetic specificity is of great value. These findings have clinical relevance since OT/AVP have a role in attention toward social cues and shared attentions, which are impaired in children with ADHD.

Factors associated with attention-deficit/hyperactivity disorder among Tunisian children

Introduction

Attention-deficit/hyperactivity disorder (ADHD) is a chronic neurodevelopmental condition that affects millions of children and adolescents worldwide. Knowledge of risk factors associated with ADHD may reduce its prevalence and its severe impact on patient's quality of life. The aim of this study was to identify risk factors associated with ADHD and to discuss their involvement in the genesis of the disorder.

Methods

This is a case-control study involving a first group of 74 children (mean age = 9 years) diagnosed with ADHD. The second group included 80 healthy control children. They were randomly selected and matched for age and gender. A literature-based questionnaire assessing the socio-demographic data, biological and environmental factors associated with ADHD was administered to the parents. The diagnosis of ADHD group was made by a trained child psychiatrist according to the DSM-5 criteria supplemented by the Conners scales of parents and teachers. For the control group, we added to the questionnaire the MINI-kid section of ADHD to screen for possible presence of ADHD symptoms. Univariate then multivariate analyses were conducted to identify factors associated with ADHD.

Results

Several factors were more prevalent in children with ADHD than in controls: disturbed family dynamics, low socio-economic status, family history of psychiatric and organic pathologies, and particularly several early environmental factors, including passive smoking during pregnancy, prematurity, fetal distress, caesarean delivery and low birth weight. In the early childhood period, early exposure to television was also strongly associated with ADHD. However, the multivariate model conducted to determine the variables independently associated with ADD/ADHD revealed only three determining factors: passive smoking during pregnancy (OR = 4.60 [2.14, 9.94]; p < 0.001), acute fetal distress (OR = 5.08 [1.47, 17.52]; p = 0.01), and familial psychiatric history (OR = 9.37 [2.46, 35.59]; p = 0.001).

Discussion

The recognition of factors involved in the genesis of ADHD within different ethnic populations may help understanding and broaden our knowledge of this disorder to develop targeted strategies for prevention and early intervention. Further participants with more robust statistical output are required to confirm our findings to a more generalized population.

Long-term effects of attention deficit hyperactivity disorder (ADHD) on social functioning and health care outcomes

INTRODUCTION

Research on the long-term effects of treatment for attention deficit hyperactivity disorder (ADHD) on educational and social outcomes is limited. This study aims to evaluate long-term social functioning outcomes in patients with ADHD and the potential effects of pharmacological treatment for ADHD.

METHODS

We used National Patient Registry data from 1995 to 2016 to identify patients diagnosed with ADHD and those collecting ADHD medication. Eligible patients were under 30 years old or had reached 30 between 2005 and 2016, ensuring a minimum 10-year observation period. A case-control design was applied, matching ADHD patients in a ratio of 1:4 with the general population based on age, sex, and residential municipality at the index year.

RESULTS

Patients with ADHD experienced substantial socioeconomic difficulties, indicated by increased direct health care costs, higher rates of psychiatric comorbidities, and greater co-medication use compared with controls. No association was found between adherence to ADHD medication and completion of education at age 30 years. Adherence to ADHD medication appeared to negatively impact employment status at age 30, confounded by the severity of psychiatric comorbidity.

CONCLUSIONS

Despite available treatments, patients with ADHD lag in achieving social functioning outcomes. Further research is needed to better understand how to support patients with ADHD in order to close the gaps in health and socioeconomic status.

Association between some environmental risk factors and attention-deficit hyperactivity disorder among children in Egypt: a case-control study

BACKGROUND

Attention-Deficit Hyperactivity Disorder (ADHD) is a complex disease that negatively impacts the social and academic/occupational activities of children and is more common in boys than in girls.

METHODS

This case-control study aimed to assess the association between some environmental risk factors and ADHD among children in Alexandria, Egypt. It was carried out at the outpatient clinics of El Shatby Pediatric University Hospital in Alexandria, Egypt, with 252 children (126 cases and 126 controls). Hair samples were collected for analysis of lead and manganese levels using Atomic Absorption Spectrophotometer. A pre-designed interview questionnaire was used to determine the important environmental risk factors that may be related to ADHD.

RESULTS

Children from parents with low levels of education, living in crowded houses, and occupational exposure to chemical agents were found to be risk factors for ADHD. The mean ± SD hair lead level in ADHD children was 2.58 ± 1.95, while in controls was 1.87 ± 0.92, with a statistically significant difference (p < 0.001). The mean ± SD hair manganese level in ADHD children was 2.10 ± 1.54, while in controls was 1.11 ± 0.69, with a statistically significant difference (p < 0.001). The logistic regression model revealed that six factors had a significant association with ADHD: using of newspapers to wrap food 3 or more times a week (adjusted odds ratio (AOR) = 105.11, 95% CI: 11.18-988.26), daily TV watching by child for more than 5 h (AOR = 63.96, 95% CI: 2.56-1601.32), child's eating commercially packed noodles 3 times or more per week (AOR = 57.73, 95% CI: 3.77-593.93), using unpackaged flour in cooking (AOR = 44.47, 95% CI: 1.83-629.80), eating sweets daily by child (AOR = 6.82, 95% CI: 1.23-37.94), and lastly elevated hair Manganese level (AOR = 3.57, 95% CI: 1.24-10.29).

CONCLUSIONS

ADHD is a multi-factorial disorder, where many environmental risk factors contribute to its development. Future efforts to determine the best preventive strategy in Egypt must be based on a better knowledge of the role of environmental risk factors in the etiology of the disorder. Eliminating non-essential uses of lead and providing public education regarding the importance of safe disposal of lead-acid batteries and computers are necessary.

Physical activity for children and adolescents with attention deficit hyperactivity disorder: a protocol of a systematic review and meta-analysis

INTRODUCTION

Attention deficit hyperactivity disorder (ADHD) is a common neurodevelopmental disorder among children and adolescents. The disorder negatively influences their academic performance and social relations, and their quality of life (QoL) is lower than that of peers without ADHD. The majority of children and adolescents with ADHD are treated with medication that potentially has an insufficient effect or frequently occurring adverse events. Physical activity is thought to alter the physiology of ADHD by affecting the same catecholaminergic system in the brain which is targeted by medication.

METHODS AND ANALYSIS

This protocol is written in accordance with the 'Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols' guideline. Randomised clinical trials with participating children and adolescents between the ages of 3 and 18 years with a primary diagnosis of ADHD or hyperkinetic disorder will be included in the systematic review. The main objective of the review is to examine the effect of physical activity on QoL, executive functions, symptoms and functional impairment in this population. Previous systematic reviews on the effect of physical activity in children and adolescents with ADHD have several methodological and conceptual limitations. These reviews, for example, included both randomised and non-randomised clinical trials or had restrictions regarding the frequency and intensity of the physical activity interventions they included. The present review will include the newest studies in the field and follow the main principles outlined in the 'Cochrane Handbook for Systematic Reviews of Interventions'. Furthermore, it will be the first review in the field to include QoL as an outcome and to apply trial sequential analysis as part of the meta-analysis.

ETHICS AND DISSEMINATION

As the systematic review is a secondary analysis of data from primary trials, approval from an ethics committee is not required. The results of the review will be published in a peer-reviewed scientific journal and presented at relevant conferences.

TRIAL REGISTRATION NUMBER

This protocol was registered with the International Prospective Register of Systematic Reviews (PROSPERO) on 16 August 2024 (CRD42024576670).

Association between maternal exercise during pregnancy and attention-deficit/hyperactivity disorder among preschool children in Southwest China

Objective

Maternal moderate-intensity exercise during pregnancy has important health benefits for the offspring, however, less is known about its association with offspring attention-deficit/hyperactivity disorder (ADHD). This study aimed to explore the association between maternal exercise during pregnancy and ADHD among preschool children in Southwest China.

Methods

A web-based cross-sectional study was performed in 2021, and the revised Conners Parental Symptom Questionnaire and maternal exercise during pregnancy were obtained through a self-reported structured questionnaire. A binary logistic regression model was used to assess the association between maternal exercise during pregnancy and the likelihood of childhood ADHD after adjustment for covariates.

Results

A total of 4,184 preschool children aged 3-6 years were included in our final analysis. Children whose mothers exercised for <20 min per day were more likely to be at risk of ADHD (6.3%), compared to those whose mothers exercised for more than 40 min (3.1%) or 20-40 min (2.8%) per day. Daily exercise of <20 min during pregnancy was associated with higher odds of childhood ADHD (adjusted OR = 2.11; 95% CI: 1.41, 3.16) after multivariable adjustment. The association of maternal exercise during pregnancy with childhood ADHD was similar in subgroups stratified by child's sex, and by maternal smoking, sleep duration and gestational anemia during pregnancy.

Conclusion

Our findings highlight the importance of maternal moderate-intensity exercise during pregnancy for the prevention of childhood ADHD. Prospective studies are needed to confirm our findings in the future.

Childhood lead exposure increases the risk of attention-deficit-hyperactivity disorder: A meta-analysis

Environmental lead exposure has been a much-discussed risk factor for the development of ADHD for decades. However, due to methodological shortcomings, the existing research on this topic is highly inconsistent. We will attempt to clarify this question by performing a meta-analysis based on a systematic literature search until February 2024 including different databases such as Pubmed and Google Scholar. The effects of environmental lead exposure were synthesized by odds ratios. A random effects model was deployed with a Paule-Mandel estimator using Hedges' invariance weighting. In addition, we carried out sensitivity analyses to examine the robustness of effects, including the detection of outliers, publication bias, p-hacking and moderating variables. In total, 14 studies with 14 effect sizes were included which had investigated the effects of lead exposure on the development of ADHD. The analyses were based on a final sample size of N = 7618 with n = 2554 ADHD cases (33,53 %) and n = 5064 healthy controls (66.47 %). Our results show that lead exposure was significantly associated with a higher risk of ADHD development. Regression analyses demonstrated that increased age of participants and increased lead significantly enhanced the risk of ADHD. Summing up we present novel results concerning the relationship between environmental lead exposure and the development of ADHD, while discussing underlying pathomechanisms as well as limitations. Finally, we provide recommendations for future studies and public health policies.

Trajectories of attention problems in preschoolers born very preterm

BACKGROUND

Children born preterm are at heightened risk for neurodevelopmental impairment, including specific deficits in attention. Few studies have investigated change over time in attention problems prior to school entry. The current study aims to describe trajectories of attention problems from age 2 through 5 years in a cohort of children born <30 weeks of gestational age (GA), identify sociodemographic, medical, and neurobehavioral characteristics associated with attention trajectories, and test whether attention problem trajectories predict the risk of a reported attention-deficit/hyperactivity disorder (ADHD) diagnosis.

METHODS

We studied 608 infants from the Neonatal Neurobehavior and Outcomes in Very Preterm Infants (NOVI) Study, a prospective, multisite study of infants born <30 weeks of GA. Parents reported on child attention problems at ages 2, 3, 4, and 5 years using the Child Behavior Checklist and the Behavior Assessment System for Children. Sociodemographic and medical characteristics were assessed via maternal interview and medical record review. Neurobehavioral characteristics were determined using neonatal and 2-year assessments. Parent report of child ADHD diagnosis was obtained. We used latent growth curve (LGC) modeling to test our study aims.

RESULTS

A linear LGC model provided the best fit to the data. The average trajectory of attention problems evidenced low initial levels of symptoms and little change over time, yet there was significant heterogeneity in both initial levels and change over time. Individual differences in trajectory parameters were associated with sociodemographic, medical, environmental, and neurobehavioral characteristics. Children with higher initial levels of attention problems as well as steeper increases in attention problems over time were more likely to have a reported ADHD diagnosis.

CONCLUSIONS

There is significant heterogeneity in trajectories of attention problems from age 2 to 5 in children born <30 weeks of GA and these differences have clinical relevance. These data could inform follow-up guidelines for preterm infants.

The Interaction Between Attention Deficit and Hyperactivity Disorder and Nutrition

PURPOSE OF REVIEW

This review aims to explore the relationship between Attention Deficit Hyperactivity Disorder (ADHD) and nutrition. ADHD, a neurodevelopmental disorder, has been examined in relation to dietary factors through various metabolic pathways, with a focus on the role of nutrition in symptom management. Unhealthy dietary patterns, particularly those characteristics of Western diets, are believed to exacerbate ADHD symptoms through these mechanisms. In contrast, dietary interventions such as intermittent fasting, which offer greater flexibility in application, have been proposed as potential strategies to alleviate ADHD symptoms. While further research in this area is expected to contribute significantly to the field, this review also provides researchers with a brief perspective on the challenges and limitations associated with experimental ADHD studies. Therefore, this study aims to offer a comprehensive evaluation of the interaction between ADHD and nutrition, providing researchers with an integrative approach to the topic.

RECENT FINDINGS

Western dietary patterns have been found to negatively impact gut barrier integrity, synaptic plasticity, insulin resistance, and oxidative stress. On the other hand, the intermittent fasting diet model, which offers practical flexibility, is thought to be a potentially supportive treatment in managing ADHD. Furthermore, it has been concluded that various experimental models are available for ADHD research, and researchers must work within these limitations. Western diets, particularly in their negative impact on synaptic plasticity and other key metabolic pathways involved in ADHD, can worsen the disorder's symptoms. Intermittent fasting emerges as a promising dietary alternative that may mitigate these adverse effects.

Evaluation of ADHD knowledge and awareness among healthcare college interns in Riyadh, Saudi Arabia

Background

Attention deficit hyperactivity disorder (ADHD), a neuropsychiatric disorder, is common in children and can persist into adulthood. With or without hyperactivity, it involves chronic impulsivity and inattention. Despite being a widespread illness, there is little research on ADHD knowledge and awareness among health college interns in Riyadh, KSA. Therefore, this study examined health college interns' knowledge and awareness in Riyadh, Saudi Arabia's capital.

Methods

A cross-sectional study using a self-administered validated survey was used to gather demographics as well as knowledge and awareness scores in King Saud University, King Saud Bin Abdulaziz University for Health Sciences (KSAU-HS), Imam Mohammed ibn Saud, and Princess Nourah Bint Abdulrahman, and one private Almaarefa University.

Results

This study included 322 health college interns aged 18-24; 55% were males. The Saudi Professional Practice Licensure Exams (SPPLE) were passed by 65.5% of participants from King Saud University and KSAU-HS, Riyadh's leading medical and pharmaceutical universities. They are evenly split throughout the four GPA categories. The interns knowledgeable and aware of ADHD (scored ≥ 13 on a 20-scale score) constituted 68% of the interns. Interns who passed Saudi Professional Practice Licensure Exams graduated from pharmacy and medicine schools, and had ≥4.5 or more GPAs were more knowledgeable than other interns.

Conclusion

As per our research, most health college interns in Riyadh were aware of ADHD; however, medical and pharmacy interns were more knowledgeable than others. This suggests that other health colleges should revamp their ADHD and neurological illness topics curricula.

Maternal asthma and asthma exacerbation during pregnancy and attention-deficit/hyperactivity disorder in offspring: a population-based cohort study

The link between inflammatory disorders, such as asthma, and attention deficit hyperactivity disorder (ADHD) is attracting increasing attention but few studies have examined cross-generational associations. We sought to examine associations of maternal asthma and asthma exacerbation during pregnancy, as well as paternal asthma, with the risk of ADHD in children. This population-based cohort study used data from the Taiwan National Health Insurance Research Database from 2004 to 2017. Cox regression models compared the risk of ADHD in children of parents with and without asthma, adjusting for parental sociodemographic, physical, and mental health conditions, as well as the child's birth weight, and number of births. A sibling control approach was employed to compensate for unmeasured confounders of asthma exacerbation during pregnancy. In the fully adjusted models, maternal and paternal asthma were both significantly associated with an increased risk of ADHD in offspring, with hazard ratios (HRs) of 1.36 (1.31-1.40) and 1.10 (1.05-1.14), respectively. Acute asthma exacerbation during pregnancy was not associated with the risk of further offspring ADHD (adjusted HR 1.00, 95% CI: 0.75-1.34). Both maternal and paternal asthma are associated with an increased risk of ADHD in offspring. The risk was higher from maternal asthma. However, no such association was found with maternal asthma exacerbation during pregnancy of sibling comparison.

Gene - maltreatment interplay in adult ADHD symptoms: main role of a gene-environment correlation effect in a Brazilian population longitudinal study

Childhood maltreatment correlates with attention-deficit/hyperactivity disorder (ADHD) in previous research. The interaction between ADHD genetic predisposition and maltreatment's impact on ADHD symptom risk remains unclear. We aimed to elucidate this relationship by examining the interplay between a polygenic score for ADHD (ADHD-PGS) and childhood maltreatment in predicting ADHD symptoms during young adulthood. Using data from the 2004 Pelotas (Brazil) birth cohort comprising 4231 participants, we analyzed gene-environment interaction (GxE) and correlation (rGE). We further explored rGE mechanisms through mediation models. ADHD symptoms were assessed at age 18 via self-report (Adult Self Report Scale - ASRS) and mother-reports (Strength and Difficulties Questionnaire - SDQ). The ADHD-PGS was derived from published ADHD GWAS meta-analysis. Physical and psychological child maltreatment was gauged using the Parent-Child Conflict Tactics Scale (CTSPC) at ages 6 and 11, with a mean score utilized as a variable. The ADHD-PGS exhibited associations with ADHD symptoms on both ASRS (β = 0.53; 95% CI: 0.03; 1.03, p = 0.036), and SDQ (β = 0.20; 95% CI: 0.08; 0.32, p = 0.001) scales. The total mean maltreatment score was associated with ADHD symptoms using both scales [(βASRS = 0.51; 95% CI: 0.26;0.77) and (βSDQ = 0.24; 95% CI: 0.18;0.29)]. The ADHD-PGS was associated with total mean maltreatment scores (β = 0.09; 95% CI: 0.01; 0.17; p = 0.030). Approximately 47% of the total effect of ADHD-PGS on maltreatment was mediated by ADHD symptoms at age 6. No evidence supported gene-environment interaction in predicting ADHD symptoms. Our findings underscore the significant roles of genetics and childhood maltreatment as predictors for ADHD symptoms in adulthood, while also indicating a potential evocative mechanism through gene-environment correlation.

Association between early-life mosquito repellents exposure and ADHD-like behaviours

BACKGROUND

Limited research has explored the impact of mosquito repellents exposure during early life on ADHD symptoms. This study aimed to explore the associations of exposure to mosquito repellents from pregnancy to 3 years old and the prevalence of ADHD-like behaviours among children aged 3-9 years, and further identify the sensitive exposure period.

METHODS

A cross-sectional study was conducted, including 12 275 children in Hefei City, China. Exposure was self-reported via primary caregivers. ADHD-like behaviours were measured by the Swanson, Nolan and Pelham, version IV scale (SNAP-IV), and Conners' Parent Rating Scale (CPRS). Cross-over analysis, binary logistic regression and linear regression were employed.

RESULTS

After adjusting for confounding variables, early-life exposure to mosquito repellents was associated with a higher risk of ADHD-like behaviours (OR = 1.81, 95% CI = 1.49-2.19). By comparing the strength of the association for each subgroup, we found exposure during 1-3 years old was a sensitive period (OR = 1.89, 95% CI = 1.25-2.87) by the cross-over analysis. Furthermore, we found a dose-response relationship in which the likelihood of ADHD-like behaviours increased with children's early-life mosquito repellents exposure dose.

CONCLUSIONS

Early-life exposure to mosquito repellents is linked with an elevated risk of ADHD-like behaviours in children, with a sensitive period identified during 1-3 years old.

Parental mental health during preconception years in association with offspring attention deficit hyperactivity disorder (ADHD): a systematic review protocol

INTRODUCTION

Attention deficit hyperactivity disorder (ADHD) is a neuropsychiatric condition prevalent in both children and adults. With growing awareness of the importance of the preconception period in health, it is essential to understand whether preconception parental mental health and related factors are related to onset of offspring ADHD. This protocol presents the methodology for undertaking a systematic review to investigate associations between parental mental health and/or psychotropic use during the preconception years and offspring ADHD.

METHODS AND ANALYSIS

Peer-reviewed literature will be identified by searching relevant electronic databases including Medline complete, Embase, PsycINFO and CINAHL; reference lists of eligible articles will be hand searched and grey literature considered. Eligible study designs include population-based and/or clinically based cohort or case-control studies. The primary exposure and outcome of interest is parental history of mental health conditions in the preconception period and offspring ADHD, respectively (ie, according to semistructured interviews/confirmed diagnosis by a relevant health professional or screening instruments). Critical appraisal will be undertaken. A descriptive synthesis will be presented including characteristics of the included studies, critical appraisal scores and a summary of main findings (eg, presented in tables, text and figures). A meta-analysis will be conducted, if possible, and statistical techniques will be employed if heterogeneity is detected.

ETHICS AND DISSEMINATION

Ethical permissions are not required for this systematic review since the study will only use published data. Findings from this systematic review will be published in a peer-reviewed scientific journal/presented at national and international conferences relevant to the field.

PROSPERO REGISTRATION NUMBER

CRD42023460379.

Attention-deficit/hyperactivity disorder in children with epilepsy: A systematic review and meta-analysis of prevalence and risk factors

OBJECTIVE

To evaluate the prevalence of and risk factors for attention-deficit/hyperactivity disorder (ADHD) in children with epilepsy (CWE).

METHODS

We conducted a systematic search in PubMed and Embase for the meta-analysis. The pooled prevalence of ADHD was calculated using a random-effects model; subgroup analyses were performed to explore heterogeneity. We collected raw data from articles reporting potential risk factors, which were included in the subsequent risk factor analysis.

RESULTS

Forty-six articles met the inclusion criteria for the meta-analysis, which showed a pooled ADHD prevalence of 30.7% in CWE, with a predominance of the inattentive subtype of ADHD; the heterogeneity of prevalence was related to population source/study setting (clinic based, community based, or database based) and method of ADHD diagnosis (with or without clinical review). Risk factors for ADHD in epilepsy included younger age, intellectual/developmental disabilities, a family history of epilepsy, earlier epilepsy onset, absence epilepsy, more frequent seizures, and polytherapy; In contrast, risk factors such as sex, generalized epilepsy or seizures, epilepsy etiology, and electroencephalogram abnormalities were not significantly associated with the occurrence of ADHD.

SIGNIFICANCE

The prevalence of ADHD in CWE is high and several potential risk factors are associated with it. This study contributes to a better understanding of ADHD in epilepsy for screening and treatment.

PLAIN LANGUAGE SUMMARY

This systematic review summarizes the prevalence of attention-deficit/hyperactivity disorder (ADHD) occurring in children with epilepsy and analyses the risk factors for comorbid ADHD in epilepsy. By reviewing 46 articles, we concluded that the overall prevalence of ADHD in children with epilepsy was 30.7% and that intellectual/developmental disabilities were the most significant risk factor for combined ADHD in children with epilepsy. This study provides a wealth of information on comorbid ADHD in epilepsy, which will help clinicians identify and treat potential ADHD in children with epilepsy in a timely manner.

Longitudinal relationship between oppositional defiant disorder symptoms and attention-deficit/hyperactivity disorder symptoms in Chinese children: insights from cross-lagged panel network analyses

Oppositional defiant disorder (ODD) and attention-deficit/hyperactivity disorder (ADHD) are two of the most common childhood mental disorders, and they have substantial comorbidity. The developmental precursor model has long been widely used to explain the mechanisms of comorbidity between ODD and ADHD, however whether it is equally effective at the symptomatic level is unclear. Therefore, this study aimed to (a) examine the stability of the ODD and ADHD comorbidity network in a longitudinal sample of high-risk children in China; and (b) examine the longitudinal relationship between the ODD and ADHD symptom networks based on a developmental precursor model. Two hundred sixty-three Chinese children aged 6 to 13 years with ODD and/or ADHD were assessed for symptoms of ODD and ADHD in two surveys conducted 1 year apart. We used data from these two time points to construct two cross-sectional networks and a cross-lagged panel network (CLPN) to explore the symptom network for comorbidity of ODD and ADHD. The analysis shows that: (1) the two cross-sectional networks are highly similar in terms of structure, existence of edges, centrality estimates, and the invariance test shows that there is no significant difference between them. The symptoms "follow through", "interrupts/intrudes", "difficulty playing quietly" and "concentration" had the highest expected influence centrality at both time points. (2) Combined with the results of the cross-sectional and cross-lagged networks, we found that "annoy" and "blame" are potential bridge symptoms between the ODD and ADHD symptom networks. The symptom "annoy" forms a reciprocal predictive relationship with "interrupts/intrudes", while "blame" unidirectionally predicts "close attention". In addition, we found that "vindictive" predicted numerous ADHD symptoms, whereas "angry" was predicted by numerous ADHD symptoms. The findings emphasize the broad predictive relationship between ODD and ADHD symptoms with each other, and that ODD symptoms may lead to activation of the ADHD symptom network and vice versa. These findings suggest that the developmental precursor model at the symptom level may partially explain the comorbidity mechanisms of ODD and ADHD, and future studies should further investigate the underlying multiple mechanisms.

Differential Impact of Serotonin Signaling Methylphenidate on Young versus Adult: Insights from Behavioral and Dorsal Raphe Nucleus Neuronal Recordings from Freely Behaving Rats

Methylphenidate (MPD) remains a cornerstone pharmacological intervention for managing ADHD, yet its increasing usage among ordinary youth and adults outside clinical contexts necessitates a thorough investigation into its developmental effects. This study seeks to simultaneously investigate the behavioral and neuronal changes within the dorsal raphe (DR) nucleus, a center of serotonergic neurons in the mammalian brain, before and after the administration of varying doses of acute and chronic MPD in freely behaving young and adult rats implanted with DR recording electrodes. Wireless neuronal and behavioral recording systems were used over 10 consecutive experimental days. Eight groups were examined: saline, 0.6, 2.5, and 10.0 mg/kg MPD for both young and adult rats. Six daily MPD injections were administered on experimental days 1 to 6, followed by a three-day washout period and MPD re-administration on experimental day 10 (ED10). The analysis of neuronal activity recorded from 504 DR neurons (DRNs) in young rats and 356 DRNs in adult rats reveals significant age-dependent differences in acute and chronic MPD responses. This study emphasizes the importance of aligning electrophysiological evaluations with behavioral outcomes following extended MPD exposure, elucidating the critical role of DRNs and serotonin signaling in modulating MPD responses and delineating age-specific variations in young versus adult rat models.

The pooled prevalence of attention-deficit/hyperactivity disorder among children and adolescents in Ethiopia: A systematic review and meta-analysis

BACKGROUND

Attention-deficit/hyperactivity disorder is one of the most common childhood neurobehavioral disorders, which has a serious negative effect on educational achievement, peer relationships, social functioning, behavior, and self-esteem of children. However, the pooled prevalence of attention-deficit/hyperactivity disorder is not well known in Ethiopia. Therefore, the main objective of this systematic review and meta-analysis is to estimate the pooled prevalence of attention-deficit/hyperactivity disorder among children and adolescents in Ethiopia.

METHODS

PubMed, HINARI, Science Direct, Psych INFO, Google Scholar, African Journals Online, and cross-referenced were searched to identify relevant articles. Quality appraisal was done using the Joanna Briggs Institute checklist. Heterogeneity was tested using the I-square statistics. Publication bias was tested using a funnel plot visual inspection. Further, trim and fill analysis was done to correct publication bias.Forest plots and tables were used to present results. The random effect model was used to compute the pooled prevalence of attention-deficit/hyperactivity disorder among children and adolescents.

RESULTS

The overall pooled prevalence of attention-deficit/hyperactivity disorder among children and adolescents in Ethiopia was 14.2% (95% CI: 8.48, 22.83). Being male (OR: 2.19, 95% CI: 1.54; 3.12), being aged 6-11 years (OR: 3.67, 95% CI: 1.98; 6.83), low family socioeconomic status (OR: 3.45 95% CI: 2.17; 5.47), maternal complication during pregnancy (OR: 3.29, 95% CI: 1.97; 5.51) and family history of mental illness (OR: 3.83, 95% CI:2.17; 6.77) were factors associated with a higher odds of attention-deficit/hyperactivity disorder among children and adolescents.

CONCLUSIONS

The overall pooled prevalence of attention-deficit/hyperactivity disorder among children and adolescents is high in Ethiopia as compared to previous literature. To reduce the prevalence of attention-deficit/hyperactivity disorder among children and adolescents, emphasis has to be given to prevention, early detection, and management of pregnancy-related complications. Moreover, parents with mental illness should be supported and properly treated to reduce the impact of hostile parenting on their child's health.

TRIAL REGISTRATION

Registered in PROSPERO with ID: CRD42024536334.

Maternal smoking cessation in the first trimester still poses an increased risk of attention-deficit/hyperactivity disorder and learning disability in offspring

Background

Studies have found maternal smoking during pregnancy was linked to attention-deficit/hyperactivity disorder (ADHD) risk. It is unclear if maternal smoking cessation during pregnancy lowers ADHD and learning disability (LD) risk in offspring. This study aimed to explore the associations between maternal smoking cessation during pregnancy and ADHD and LD risk in offspring.

Methods

Data from the National Health and Nutrition Examination Survey 1999-2004 (8,068 participants) were used. Logistic regression was used to analyze the associations between maternal smoking and smoking cessation during pregnancy and ADHD and LD risk in offspring.

Results

Compared to non-smokers' offspring, maternal smoking during pregnancy increased the risk of ADHD (odds ratios [OR] = 2.07, 95% confidence interval [CI]: 1.67-2.56) and LD (OR = 1.93, 95% CI: 1.61-2.31) in offspring, even if mothers quit smoking later (ORADHD = 1.91, 95%CIADHD: 1.38-2.65, ORLD = 1.65, 95%CILD: 1.24-2.19). Further analysis of the timing of initiation of smoking cessation during pregnancy revealed that, compared to non-smokers' offspring, maternal quitting smoking in the first trimester still posed an increased risk of ADHD (OR = 1.72, 95% CI: 1.41-2.61) and LD (OR = 1.52, 95% CI: 1.06-2.17) in offspring. Maternal quitting smoking in the second or third trimester also had a significantly increased risk of ADHD (OR = 2.13, 95% CI: 1.26-3.61) and LD (OR = 1.82, 95% CI: 1.16-2.87) in offspring. Furthermore, maternal smoking but never quitting during pregnancy had the highest risk of ADHD (OR = 2.17, 95% CI: 1.69-2.79) and LD (OR = 2.10, 95% CI: 1.70-2.58) in offspring. Interestingly, a trend toward a gradual increase in the risk-adjusted OR for ADHD and LD risk was observed among the three groups: maternal quitting smoking in the first trimester, maternal quitting smoking in the second or third trimester, and maternal smoking but never quitting.

Conclusion

Maternal smoking cessation in the first trimester still poses an increased risk of ADHD and LD in offspring. Furthermore, it seems that the later the mothers quit smoking during pregnancy, the higher the risk of ADHD and LD in their offspring. Therefore, early intervention of maternal smoking in preconception and prenatal care is vital for offspring neurodevelopment.

Review of the Brain's Behaviour after Injury and Disease for Its Application in an Agent-Based Model (ABM)

The brain is the most complex organ in the human body and, as such, its study entails great challenges (methodological, theoretical, etc.). Nonetheless, there is a remarkable amount of studies about the consequences of pathological conditions on its development and functioning. This bibliographic review aims to cover mostly findings related to changes in the physical distribution of neurons and their connections-the connectome-both structural and functional, as well as their modelling approaches. It does not intend to offer an extensive description of all conditions affecting the brain; rather, it presents the most common ones. Thus, here, we highlight the need for accurate brain modelling that can subsequently be used to understand brain function and be applied to diagnose, track, and simulate treatments for the most prevalent pathologies affecting the brain.

The neural and genetic underpinnings of different developmental trajectories of Attention-Deficit/Hyperactivity Symptoms in children and adolescents

BACKGROUND

The trajectory of attention-deficit hyperactivity disorder (ADHD) symptoms in children and adolescents, encompassing descending, stable, and ascending patterns, delineates their ADHD status as remission, persistence or late onset. However, the neural and genetic underpinnings governing the trajectory of ADHD remain inadequately elucidated.

METHODS

In this study, we employed neuroimaging techniques, behavioral assessments, and genetic analyses on a cohort of 487 children aged 6-15 from the Children School Functions and Brain Development project at baseline and two follow-up tests for 1 year each (interval 1: 1.14 ± 0.32 years; interval 2: 1.14 ± 0.30 years). We applied a Latent class mixed model (LCMM) to identify the developmental trajectory of ADHD symptoms in children and adolescents, while investigating the neural correlates through gray matter volume (GMV) analysis and exploring the genetic underpinnings using polygenic risk scores (PRS).

RESULTS

This study identified three distinct trajectories (ascending-high, stable-low, and descending-medium) of ADHD symptoms from childhood through adolescence. Utilizing the linear mixed-effects (LME) model, we discovered that attention hub regions served as the neural basis for these three developmental trajectories. These regions encompassed the left anterior cingulate cortex/medial prefrontal cortex (ACC/mPFC), responsible for inhibitory control; the right inferior parietal lobule (IPL), which facilitated conscious focus on exogenous stimuli; and the bilateral middle frontal gyrus/precentral gyrus (MFG/PCG), accountable for regulating both dorsal and ventral attention networks while playing a crucial role in flexible modulation of endogenous and extrinsic attention. Furthermore, our findings revealed that individuals in the ascending-high group exhibited the highest PRS for ADHD, followed by those in the descending-medium group, with individuals in the stable-low group displaying the lowest PRS. Notably, both ascending-high and descending-medium groups had significantly higher PRS compared to the stable-low group.

CONCLUSIONS

The developmental trajectory of ADHD symptoms in the general population throughout childhood and adolescence can be reliably classified into ascending-high, stable-low, and descending-medium groups. The bilateral MFG/PCG, left ACC/mPFC, and right IPL may serve as crucial brain regions involved in attention processing, potentially determining these trajectories. Furthermore, the ascending-high pattern of ADHD symptoms exhibited the highest PRS for ADHD.

Early childhood exposures to phthalates in association with attention-deficit/hyperactivity disorder behaviors in middle childhood and adolescence in the ReCHARGE study

BACKGROUND

Early-life exposure to phthalates alters behaviors in animals. However, epidemiological evidence on childhood phthalate exposure and attention-deficit/hyperactivity disorder (ADHD) behaviors is limited.

METHODS

This study included 243 children from the ReCHARGE (Revisiting Childhood Autism Risks from Genetics and Environment) study, who were previously classified as having autism spectrum disorder (ASD), developmental delay, other early concerns, and typical development in the CHARGE case-control study. Twenty phthalate metabolites were measured in spot urine samples collected from children aged 2-5 years. Parents reported on children's ADHD symptoms at ages 8-18 years using Conners-3 Parent Rating Scale. Covariate-adjusted negative binomial generalized linear models were used to investigate associations between individual phthalate metabolite concentrations and raw scores. Weighted quantile sum (WQS) regression with repeated holdout validation was used to examine mixture effects of phthalate metabolites on behavioral scores. Effect modification by child sex was evaluated.

RESULTS

Among 12 phthalate metabolites detected in >75% of the samples, higher mono-2-heptyl phthalate (MHPP) was associated with higher scores on Inattentive (β per doubling = 0.05, 95% confidence interval [CI]: 0.02, 0.08) and Hyperactive/Impulsive scales (β = 0.04, 95% CI: 0.00, 0.07), especially among children with ASD. Higher mono-carboxy isooctyl phthalate (MCiOP) was associated with higher Hyperactivity/Impulsivity scores (β = 0.07, 95% CI: -0.01, 0.15), especially among typically developing children. The associations of the molar sum of high molecular weight (HMW) phthalate metabolites and a phthalate metabolite mixture with Hyperactivity/Impulsivity scores were modified by sex, showing more pronounced adverse associations among females.

CONCLUSION

Exposure to phthalates during early childhood may impact ADHD behaviors in middle childhood and adolescence, particularly among females. Although our findings may not be broadly generalizable due to the diverse diagnostic profiles within our study population, our robust findings on sex-specific associations warrant further investigations.

The causal impact of maternal smoking around birth on offspring ADHD: A two-sample Mendelian randomization study

BACKGROUND

The previous literature highlights a relationship between maternal smoking around birth (MSAB) and offspring attention-deficit/hyperactivity disorder (ADHD). These studies have focused on the causal effects of MSAB on offspring ADHD.

METHOD

A Mendelian randomization analysis was conducted using summary statistics. Data on MSAB were obtained from a recent study including 391,992 participants. ADHD data were obtained from six sources for 246,888 participants. The present study used five methods to examine the causal impact from outcomes on exposures. The inverse variance weighted (IVW) was the main method of analysis, while the other four methods were supplementary methods.

RESULT

The IVW revealed that MSAB was a risk factor for offspring ADHD (OR: 2.54; 95 % confidence interval [CI]: 1.61-4.00, p = 6.04 × 10-5). Concerning ADHD in both sexes, MSAB was associated with females (OR = 3.96, 95 % CI: 1.99-7.90, p = 8.98 × 10-5) and males (OR = 3.74, 95 % CI: 1.74-5.72, p = 1.48 × 10-4). In different diagnosis periods for ADHD, MSAB increased the risk of childhood (OR = 3.63, 95 % CI: 2.25-5.87, p = 1.31 × 10-7), late-diagnosed (OR = 2.99, 95 % CI: 1.74-5.14, p = 7.33 × 10-5), and persistent (OR = 4.77, 95 % CI: 1.88-12.14, p = 1.03 × 10-3) ADHD. The final analysis did not reveal heterogeneity.

CONCLUSIONS

A causal impact of MSAB on offspring ADHD was observed. These findings highlight the need for careful consideration of prenatal exposure (MSAB) during the assessment of offspring ADHD. Additionally, it can provide targeted guidance for prenatal interventions. Future studies should analyze the effects of different doses of maternal smoking on ADHD.

Increased Serum Terminal Complements Complex Levels in Attention Deficit Hyperactivity Disorder Children

Background

Attention deficit hyperactivity disorder (ADHD) is a widespread neuropsychiatric disorder in both children and adolescents, which is associated with social isolation and poor academic performance. Complement proteins are regarded as a major player in inflammation and disease development for several neuropsychiatric diseases such as schizophrenia and bipolar diseases. As clarified by previous data, increased levels of complement molecules and other immunological markers as cytokines were demonstrated in these disorders. Limited studies have investigated complement proteins particularly terminal complement complex or membrane attack complex (C5b-9) among ADHD patients. The present research aims to elucidate the association between C5b-9 complex protein and ADHD.

Methods

This is a cross-sectional study. Sera were collected from Al-Hussain Teaching Medical City in Holy Karbala, Iraq, during 2019-2020. Sera were tested for C5-b9 using commercial kits by enzyme-linked immunosorbent assay (ELISA).

Results

In 90 participants included in the study, a significant increment in C5b-9 levels among ADHD patients (P=0.019) was observed. Patients with positive C5b-9 levels had a 2.76 times higher risk of developing ADHD than control subjects. The diagnostic utility for C5b-9 was statistically significant with 71.11% sensitivity, 55.6% specificity, and a high negative predictive value (97.3%).

Conclusion

The study concluded elevation of the C5b-9 terminal complements complex levels in ADHD patients, which could point to the association of complement proteins as inflammatory markers with the ADHD disease process.

Functional contribution of the intestinal microbiome in autism spectrum disorder, attention deficit hyperactivity disorder, and Rett syndrome: a systematic review of pediatric and adult studies

Introduction

Critical phases of neurodevelopment and gut microbiota diversification occur in early life and both processes are impacted by genetic and environmental factors. Recent studies have shown the presence of gut microbiota alterations in neurodevelopmental disorders. Here we performed a systematic review of alterations of the intestinal microbiota composition and function in pediatric and adult patients affected by autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), and Rett syndrome (RETT).

Methods

We searched selected keywords in the online databases of PubMed, Cochrane, and OVID (January 1980 to December 2021) with secondary review of references of eligible articles. Two reviewers independently performed critical appraisals on the included articles using the Critical Appraisal Skills Program for each study design.

Results

Our systematic review identified 18, 7, and 3 original articles describing intestinal microbiota profiles in ASD, ADHD, and RETT, respectively. Decreased Firmicutes and increased Bacteroidetes were observed in the gut microbiota of individuals affected by ASD and ADHD. Proinflammatory cytokines, short-chain fatty acids and neurotransmitter levels were altered in ASD and RETT. Constipation and visceral pain were related to changes in the gut microbiota in patients affected by ASD and RETT. Hyperactivity and impulsivity were negatively correlated with Faecalibacterium (phylum Firmicutes) and positively correlated with Bacteroides sp. (phylum Bacteroidetes) in ADHD subjects. Five studies explored microbiota-or diet-targeted interventions in ASD and ADHD. Probiotic treatments with Lactobacillus sp. and fecal microbiota transplantation from healthy donors reduced constipation and ameliorated ASD symptoms in affected children. Perinatal administration of Lactobacillus sp. prevented the onset of Asperger and ADHD symptoms in adolescence. Micronutrient supplementation improved disease symptomatology in ADHD without causing significant changes in microbiota communities' composition.

Discussion

Several discrepancies were found among the included studies, primarily due to sample size, variations in dietary practices, and a high prevalence of functional gastrointestinal symptoms. Further studies employing longitudinal study designs, larger sample sizes and multi-omics technologies are warranted to identify the functional contribution of the intestinal microbiota in developmental trajectories of the human brain and neurobehavior.

Systematic review registration

https://clinicaltrials.gov/, CRD42020158734.

Heavy Metal and Thiol/Disulfide in Children with Attention-Deficit and Hyperactivity Disorder

Background

In the etiology of attention-deficit and hyperactivity disorder (ADHD), oxidative stress and heavy metal exposure are still controversial topics. In this study, our goal was to examine heavy metal levels and oxidative balance in newly diagnosed patients with ADHD and reveal whether heavy metal levels have an effect on the oxidation balance.

Methods

The study included 35 patients with newly diagnosed ADHD and 31 healthy control groups of similar age and gender. Participants' parents or caregivers completed a semi-structured questionnaire regarding their children's breastfeeding and prenatal and postnatal smoking exposures. The levels of heavy metals lead (Pb), mercury (Hg), and cadmium were measured with inductively coupled plasma optical emission spectroscopy, and a unique automated spectrophotometric approach was used to quantify serum total thiol, native thiol, and disulfide quantities and ratios.

Results

The rate of smoking during pregnancy was significantly higher in the ADHD group than in the control group (P = .030). Compared to the control group, the native and total thiol levels of children with ADHD were significantly higher (P < .001). Likewise, the ADHD group had significantly higher Hg levels compared to the control group (P = .002). Cadmium levels were substantially greater in the control group compared to the ADHD group (P < .001). However, there was no significant difference between Pb levels in the ADHD and the control group (P = .844).

Conclusion

Exposure to Hg and prenatal smoking may contribute to the development of ADHD in childhood. In response to oxidative stress, the young brains of children with ADHD may enhance their antioxidant levels.

The Association Between Repeated Measured Febrile Episodes During Early Childhood and Attention Deficit Hyperactivity Disorder: A Large-Scale Population-Based Study

OBJECTIVE

We examined the association between the number, magnitude, and frequency of febrile episodes during the 0 to 4 years of life and subsequent diagnosis of ADHD.

METHODS

This population-based case-control study in an Israeli HMO, Leumit Health Services (LHS), uses a database for all LHS members aged 5 to 18 years between 1/1/2002 and 1/30/2022. The number and magnitude of measured fever episodes during the 0 to 4 years were recorded in individuals with ADHD (N = 18,558) and individually matched non-ADHD controls in a 1:2 ratio (N = 37,116).

RESULTS

A significant, independent association was found between the number and magnitude of febrile episodes during the 0 to 4 years and the probability of a later diagnosis of ADHD. Children who never had a measured temperature >37.5°C had a significantly lower rate of ADHD (OR = 0.834, 95% CI [0.802, 0.866], p < .0001).

CONCLUSIONS

Febrile episodes during 0 to 4 years are associated with a significantly increased rate of a later diagnosis of ADHD in a doseresponse relationship.

Epigenome-wide association study identifies neonatal DNA methylation associated with two-year attention problems in children born very preterm

Prior research has identified epigenetic predictors of attention problems in school-aged children but has not yet investigated these in young children, or children at elevated risk of attention problems due to preterm birth. The current study evaluated epigenome-wide associations between neonatal DNA methylation and attention problems at age 2 years in children born very preterm. Participants included 441 children from the Neonatal Neurobehavior and Outcomes in Very Preterm Infants (NOVI) Study, a multi-site study of infants born < 30 weeks gestational age. DNA methylation was measured from buccal swabs collected at NICU discharge using the Illumina MethylationEPIC Bead Array. Attention problems were assessed at 2 years of adjusted age using the attention problems subscale of the Child Behavior Checklist (CBCL). After adjustment for multiple testing, DNA methylation at 33 CpG sites was associated with child attention problems. Differentially methylated CpG sites were located in genes previously linked to physical and mental health, including several genes associated with ADHD in prior epigenome-wide and genome-wide association studies. Several CpG sites were located in genes previously linked to exposure to prenatal risk factors in the NOVI sample. Neonatal epigenetics measured at NICU discharge could be useful in identifying preterm children at risk for long-term attention problems and related psychiatric disorders, who could benefit from early prevention and intervention efforts.

Serum levels of glucose, thyroid stimulating hormone, and free thyroxine in boys diagnosed with attention deficit hyperactivity disorder: a cross-sectional pilot study

BACKGROUND

Although attention deficit hyperactivity disorder (ADHD) is a common neurodevelopmental disorder, its aetiology remains unclear. We aimed to establish a relationship between ADHD diagnosis and serum levels of glucose, free thyroxine (FT4), and thyroid stimulating hormone (TSH) in primary school aged boys.

METHODS

In a cross-sectional study, we enrolled 133 participants aged 6.5-12.5 years, 67 of whom met DSM-5 criteria for ADHD and 66 healthy age-matched boys. The ADHDT test (ADHDT) was used to assess ADHD symptoms and the Wechsler Intelligence Scale for Children - Revised was used to exclude participants with cognitive deficits. The ADHD participants were tested using the Iowa Conners' Teacher Rating Scale.

RESULTS

The ADHD participants had lower glucose levels, higher TSH values, and significantly lower FT4 values than the control group. The multiple logistic regression analysis showed that TSH is a parameter that is 2.7% more likely to occur in the ADHD group. We found a significant correlation between the TSH level and the symptoms of hyperactivity (r = 0.318, p = 0.009) and impulsivity (r = 0.275, p = 0.024) as well as between the glucose level and the symptoms of hyperactivity (r = 0.312, p = 0.010).

CONCLUSIONS

Certain ADHD symptoms may correlate with certain hormonal patterns. Our results suggest that the likelihood of suffering from ADHD was lower when FT4 levels were elevated. One biochemical parameter that was significantly and independently associated with the diagnosis of ADHD was the serum TSH level.

TRIAL REGISTRATION

On June 26, 2018, at its VI session in 2018, the Ethics Committee of the Institute for Mental Health in Belgrade, Serbia, has considered and unanimously approved the conduct of the research, under the number 1704/1.

Overactivated contextual visual perception and response to a single dose of methylphenidate in children with ADHD

The pathogenesis of overactivated visual perception in attention-deficit hyperactivity disorder (ADHD) remains unclear, which is interpreted as a cognitive compensation. The existing studies have proposed that perceptual abnormalities in neurodevelopmental disorders are associated with dysfunction of the contextual knowledge system, which influences the development and formation of perception. We hypothesized that alterations in contextual states may also be responsible for inducing perceptual abnormalities in ADHD. Therefore, the present study evaluated the characteristics of pre-stimulus alpha and its response to a single dose of methylphenidate (MPH). A total of 135 Chinese children participated in the first study, including 70 children with ADHD (age = 10.61 ± 1.93 years, female = 17) and 65 age- and sex-matched control children (age = 10.73 ± 1.93 years, female = 20). The second clinical trial included 19 Chinese children with ADHD (age = 11.85 ± 1.72 years, female = 4), with an identical visual spatial search task. Pre-stimulus alpha oscillations and P1 activity were significantly greater in children with ADHD than in the controls. Overactivated pre-stimulus alpha positively predicted P1. Both pre-stimulus alpha and P1 overactivation have beneficial effects on cognitive performance in children with ADHD. No intervening effect of a single dose of MPH on the compensatory activation of pre-stimulus alpha and P1 were observed. Our findings extended the perceptual activation to the contextual knowledge system, suggesting that compensatory perception in children with ADHD is more likely to be a top-down regulated cognitive operational process.

Mapping autism's research landscape: trends in autism screening and its alignment with sustainable development goals

Introduction

Autism Spectrum Disorder is a complex neurodevelopmental syndrome that profoundly affects social interactions, communication, and sensory perception. The research traced the evolution of autism research from 2011-2022, specifically focusing on the screening and diagnosis of children and students.

Methods

Through an analysis of 12,262 publications using the PRISMA framework, bibliographic coupling, science mapping, and citation analysis, this study illuminates the growth trajectory of ASD research and significant disparities in diagnosis and services.

Results

The study indicates an increasing trend in autism research, with a strong representation of female authorship. Open Access journals show a higher average citation impact compared to their closed counterparts. A keyword co-occurrence analysis revealed four central research themes: Child Development and Support Systems, Early Identification and Intervention, Prevalence and Etiology, and Mental Health. The pandemic's onset has prioritized research areas like mental health, telehealth, and service accessibility.

Discussion

Recommendations on a global level stress the importance of developing timely biological markers for ASD, amplifying Disability Inclusion research, and personalizing mental health services to bridge these critical service gaps. These strategies, underpinned by interdisciplinary collaboration and telehealth innovation, particularly in low-resource settings, can offer a roadmap for inclusive, context-sensitive interventions at local levels that directly support SDG3's aim for health and well-being for all.

The Kynurenine Pathway in Attention-Deficit/Hyperactivity Disorder: A Systematic Review and Meta-Analysis of Blood Concentrations of Tryptophan and Its Catabolites

Preliminary evidence shows that the kynurenine pathway (KP) may be altered in attention-deficit/hyperactivity disorder (ADHD). We thus conducted a systematic review and meta-analysis exploring the peripheral blood concentrations of tryptophan catabolites (TRYCATs) in people with ADHD. We searched the main electronic databases up to 7th December 2023. Standardised mean differences (SMDs) with 95% confidence intervals (95%CIs) were used to compare TRYCAT concentrations between participants with ADHD and healthy controls (HCs). We included eight studies. Random-effects meta-analyses found higher kynurenine (SMD = 0.56; 95%CI: 0.04 to 1.08; p = 0.033; I2 = 90.3%) and lower kynurenic acid (SMD = -0.33; 95%CI: -0.49 to -0.17; p < 0.001; I2 = 0%) concentrations in people with ADHD compared to HCs. Additional analyses on drug-free children with ADHD showed higher tryptophan (SMD = 0.31; 95%CI: 0.11 to 0.50; p = 0.002; I2 = 0%) and kynurenine (SMD = 0.74; 95%CI: 0.30 to 1.17; p < 0.001; I2 = 76.5%), as well as lower kynurenic acid (SMD = -0.37; 95%CI: -0.59 to -0.15; p < 0.001; I2 = 0%) blood levels, as compared to HCs. Despite some limitations, our work provides preliminary evidence on KP alterations in ADHD that may suggest decreased neuroprotection. Further research is needed to clarify the role of the KP in ADHD.

An updated overview on the relationship between human gut microbiome dysbiosis and psychiatric and psychological disorders

There is a lot of evidence establishing that nervous system development is related to the composition and functions of the gut microbiome. In addition, the central nervous system (CNS) controls the imbalance of the intestinal microbiota, constituting a bidirectional communication system. At present, various gut-brain crosstalk routes have been described, including immune, endocrine and neural circuits via the vagal pathway. Several empirical data have associated gut microbiota alterations (dysbiosis) with neuropsychiatric diseases, such as Alzheimer's disease, autism and Parkinson's disease, and with other psychological disorders, like anxiety and depression. Fecal microbiota transplantation (FMT) therapy has shown that the gut microbiota can transfer behavioral features to recipient animals, which provides strong evidence to establish a causal-effect relationship. Interventions, based on prebiotics, probiotics or synbiotics, have demonstrated an important influence of microbiota on neurological disorders by the synthesis of neuroactive compounds that interact with the nervous system and by the regulation of inflammatory and endocrine processes. Further research is needed to demonstrate the influence of gut microbiota dysbiosis on psychiatric and psychological disorders, and how microbiota-based interventions may be used as potential therapeutic tools.

Adverse Childhood Experiences and ADHD Symptoms Among French College Students

To examine the relationship between adverse childhood experiences (ACEs) and Attention-deficit Hyperactivity Disorder (ADHD) among college students. We investigated the association between ACEs and ADHD symptoms among French college students enrolled in the i-Share cohort using multivariate logistic regression models. The sample comprised of 1062 participants with a mean age of 20.3 (SD = 2.3) of which 30.6% had no ACEs exposure, 29.6% had 1 ACE, 19.2% had 2 ACEs, and 20.6% had ≥ 3 ACEs. After controlling for potential confounders, every increase in ACE exposure heightened the risk of ADHD symptoms with the respective adjusted Odds Ratios and 95% confidence intervals: 1 ACE: 2.1 (0.7-6.3) / 2 ACEs: 4.5 (2.6-12.8)/ ≥ 3 ACEs: 5.2 (1.8-14.8). Estimates for ADHD symptoms were higher with sexual abuse, emotional and physical neglect, and bullying. Findings suggest that ACEs heighten the risk for developing ADHD symptoms among college students and bear important implications for prevention and clinical practice.

Attention-deficit/hyperactivity disorder and inflammation: natural product-derived treatments-a review of the last ten years

OBJECTIVE

Attention-deficit hyperactivity disorder (ADHD) is a psychiatric disorder characterized by symptoms of inattention, hyperactivity, and impulsivity. Stimulant medication is the main pharmacological treatment for ADHD. However, the traditional pharmacological treatments may have significant side effects; therefore, non-pharmacological approaches are needed. Thus, there has been growing interest in alternative herbal treatments. The aim of this review was to comprehensively assess the current evidence for plant-based treatment of ADHD in human and animal models, as well as their ability to modulate the inflammatory process.

METHODS

This study was an integrative review of the current evidence for the plant-based treatment of ADHD. The research involved using literature available on PubMed and Scopus databases.

FINDINGS

Spontaneously hypersensitive rats treated with baicalin exhibited significant reductions in locomotion, increased spatial learning skills, and increased levels of dopamine in the striatum. Supplementation with Sansonite improved memory and attention capacity. In human studies, Ginkgo biloba significantly improved the symptoms of inattention and reduced memory impairment. In studies conducted using Korean Red ginseng, Klamath, and Crocus sativus L., the patients showed significant improvements in symptoms of inattention and hyperactivity/impulsivity. Furthermore, we demonstrated that the identified plants modulate the inflammatory process through pro-inflammatory and anti-inflammatory cytokines, nitric oxide, Th cells, Toll-like receptor 4, and mitogen-activated protein kinases.

CONCLUSION

All the studies included in this review focused on plants with demonstrated potential against inflammatory processes, positioning them as promising candidates for ADHD treatment, due to their potential to attenuate or even prevent neuroinflammatory mechanisms.

Risk factors associated with newly diagnosed attention-deficit/hyperactivity disorder in adults: a retrospective case-control study

BACKGROUND

Knowledge of risk factors for attention-deficit/hyperactivity disorder (ADHD) may facilitate early diagnosis; however, studies examining a broad range of potential risk factors for ADHD in adults are limited. This study aimed to identify risk factors associated with newly diagnosed ADHD among adults in the United States (US).

METHODS

Eligible adults from the IQVIA PharMetrics® Plus database (10/01/2015-09/30/2021) were classified into the ADHD cohort if they had ≥ 2 ADHD diagnoses (index date: first ADHD diagnosis) and into the non-ADHD cohort if they had no observed ADHD diagnosis (index date: random date) with a 1:3 case-to-control ratio. Risk factors for newly diagnosed ADHD were assessed during the 12-month baseline period; logistic regression with stepwise variable selection was used to assess statistically significant association. The combined impact of selected risk factors was explored using common patient profiles.

RESULTS

A total of 337,034 patients were included in the ADHD cohort (mean age 35.2 years; 54.5% female) and 1,011,102 in the non-ADHD cohort (mean age 44.0 years; 52.4% female). During the baseline period, the most frequent mental health comorbidities in the ADHD and non-ADHD cohorts were anxiety disorders (34.4% and 11.1%) and depressive disorders (27.9% and 7.8%). Accordingly, a higher proportion of patients in the ADHD cohort received antianxiety agents (20.6% and 8.3%) and antidepressants (40.9% and 15.8%). Key risk factors associated with a significantly increased probability of ADHD included the number of mental health comorbidities (odds ratio [OR] for 1 comorbidity: 1.41; ≥2 comorbidities: 1.45), along with certain mental health comorbidities (e.g., feeding and eating disorders [OR: 1.88], bipolar disorders [OR: 1.50], depressive disorders [OR: 1.37], trauma- and stressor-related disorders [OR: 1.27], anxiety disorders [OR: 1.24]), use of antidepressants (OR: 1.87) and antianxiety agents (OR: 1.40), and having ≥ 1 psychotherapy visit (OR: 1.70), ≥ 1 specialist visit (OR: 1.30), and ≥ 10 outpatient visits (OR: 1.51) (all p < 0.05). The predicted risk of ADHD for patients with treated anxiety and depressive disorders was 81.9%.

CONCLUSIONS

Mental health comorbidities and related treatments are significantly associated with newly diagnosed ADHD in US adults. Screening for patients with risk factors for ADHD may allow early diagnosis and appropriate management.

Perinatal exposure to potential endocrine disrupting chemicals and autism spectrum disorder: From Norwegian birth cohort to zebrafish studies

BACKGROUND

The etiology of autism spectrum disorder (ASD) is multifactorial, involving genetic and environmental contributors such as endocrine-disrupting chemicals (EDCs).

OBJECTIVE

To evaluate the association between perinatal exposure to 27 potential EDCs and ASD among Norwegian children, and to further examine the neurodevelopmental toxicity of associated chemicals using zebrafish embryos and larvae.

METHOD

1,199 mothers enrolled in the prospective birth-cohort (HUMIS, 2002-2009) study. Breastmilk levels of 27 chemicals were measured: polychlorinated biphenyls, organochlorine pesticides, polybrominated diphenyl ethers, and perfluoroalkyl substances as a proxy for perinatal exposure. We employed multivariable logistic regression to determine association, utilized elastic net logistic regression as variable selection method, and conducted an in vivo study with zebrafish larvae to confirm the neurodevelopmental effect.

RESULTS

A total of 20 children had specialist confirmed diagnosis of autism among 1,199 mother-child pairs in this study. β-Hexachlorocyclohexane (β-HCH) was the only chemical associated with ASD, after adjusting for 26 other chemicals. Mothers with the highest levels of β-HCH in their milk had a significant increased risk of having a child with ASD (OR = 1.82, 95 % CI: 1.20, 2.77 for an interquartile range increase in ln-transformed β-HCH concentration). The median concentration of β-HCH in breast milk was 4.37 ng/g lipid (interquartile range: 2.92-6.47), and the estimated daily intake (EDI) for Norwegian children through breastfeeding was 0.03 µg/kg of body weight. The neurodevelopmental and social behavioral effects of β-HCH were established in zebrafish embryos and larvae across various concentrations, with further analysis suggesting that perturbation of dopaminergic neuron development may underlie the neurotoxicity associated with β-HCH.

CONCLUSIONS

Prenatal exposure to β-HCH was associated with an increased risk of specialist-confirmed diagnoses of ASD among Norwegian children, and the EDI surpasses the established threshold. Zebrafish experiments confirm β-HCH neurotoxicity, suggesting dopaminergic neuron disruption as a potential underlying mechanism.

The Burden of Attention-Deficit Hyperactivity Disorder (ADHD) in the Middle East and North Africa Region, 1990 to 2019

OBJECTIVE

To report the burden of ADHD in the Middle East and North Africa (MENA) region from 1990 to 2019.

METHODS

Publicly available data on the burden of ADHD were retrieved from the Global Burden of Disease study 2019. The counts and age-standardized rates (per 100,000) were presented.

RESULTS

In 2019, ADHD had an age-standardized point prevalence of 1245.1 and a years lived with disability (YLD) rate of 15.1 per 100,000 in MENA, which were 7.2% (-11 to -3.3) and 7.2% (-11.2 to -2.7) lower, respectively, than in 1990. The highest YLD rate of ADHD was found in the 10 to 14 age group and there were no remarkable differences between males and females. No clear association was found between the YLD rate and the socio-demographic index.

CONCLUSION

The burden of ADHD in the MENA region decreased over the period 1990 to 2019, and regularly updating the epidemiological information is suggested.

Exposure to environmental pollutants and attention-deficit/hyperactivity disorder: an overview of systematic reviews and meta-analyses

Although heritability estimates suggest a role for genetic components, environmental risk factors have been described as relevant in the etiology of attention deficit/hyperactivity disorder (ADHD). Several studies have investigated the role of toxicological pollution, i.e., air pollution, heavy metals, POPs, and phthalates. Clear evidence for association of ADHD and environmental factors has not been provided yet. To answer this, we have assessed all available systematic reviews and meta-analyses that focused on the association between pollutant exposure and either ADHD diagnosis or symptoms. More than 1800 studies were screened of which 14 found eligible. We found evidence of a significant role for some pollutants, in particular heavy metals and phthalates, in the increased risk of developing ADHD symptoms. However, at the current stage, data from existing literature also do not allow to weight the role of the different environmental pollutants. We also offer a critical examination of the reviews/meta-analyses and provide indications for future studies in this field. PROSPERO registration: CRD42022341496.

The impact of sleep difficulties in children with attention deficit hyperactivity disorder on the family: a thematic analysis

STUDY OBJECTIVES

Attention deficit hyperactivity disorder is a complex but common neurodevelopmental condition characterized by symptoms of inattention, hyperactivity, and impulsivity associated with a significant level of academic, social, and functional impairment. Problems around sleep frequently co-occur with attention deficit hyperactivity disorder and are thought to affect 50% to 80% of children and adults with the condition. Sleep issues typically include trouble falling asleep, bedtime resistance, night-time waking, and early rising. The impact of these problems on families and parents is profound but poorly researched.

METHODS

Semistructured interviews took place with 12 mothers of children with attention deficit hyperactivity disorder who struggle with sleep. Participants were asked about sleeping patterns and issues, methods used to improve sleep, the impact on parents' sleep and wider family life, and involvement with clinical services and support groups. Data were analyzed using thematic analysis.

RESULTS

Three themes were identified in the data: a constant battleground; the cumulative effect of lack of sleep: impact on functioning and the wider family; a mixed bag of strategies: the tried, tested, and needed. Long-term sleep issues and challenging behavior at bedtime had substantial negative effects on families. Parents experiencing sleep deprivation experienced functional impairments to daily life and well-being and strain on relationships with children and spouses.

CONCLUSIONS

Findings revealed parents were consistently and profoundly impacted by their children's sleep problems. Parents sought strategies and support in many different ways but were often unsuccessful.

CITATION

French B, Quain E, Kilgariff J, Lockwood J, Daley D. The impact of sleep difficulties in children with attention deficit hyperactivity disorder on the family: a thematic analysis. J Clin Sleep Med. 2023;19(10):1735-1741.

Two neurosubtypes of ADHD different from the clinical phenotypes

Clinical and etiological variability of attention deficit hyperactivity disorder (ADHD) presents an obstacle to understand the disorder. The aim of this study was to disentangle the heterogeneity of ADHD using neuroimaging and a semi-supervised machine learning algorithm. We collected brain structural and functional magnetic resonance imaging (MRI) data and clinical profiles of 183 children with ADHD and 396 neurotypical controls from 7 independent sites. We also used an external validation set with 750 subjects. We adopted a semi-supervised clustering method to subtype ADHD by regional volumetric measures of gray matter, white matter, and fractional amplitude of low frequency fluctuation (fALFF). In addition, split sample test, leave-one-site-out test and external validation were applied to evaluate the reproducibility and stability of ADHD subtypes. Two stable and reproducible neurosubtypes of ADHD were disclosed, which were proved by the split-sample test and leave-one-site-out validation. The structural and functional patterns of ADHD subtypes were also stable in the external validation set. The current two neurosubtypes differed in clinical manifestations and volumetric gray matter, white matter volume and fALFF patterns. The current neurosubtypes of ADHD which were different from clinical phenotypes could facilitate understanding the underlying neuropathological and neurobiological mechanism of the disorder.

Correlation of the methylomic signature of smoking during pregnancy with clinical traits in ADHD

BACKGROUND

Attention deficit/hyperactivity disorder (ADHD) is a highly prevalent childhood disorder. Maternal smoking during pregnancy is a replicated environmental risk factor for this disorder. It is also a robust modifier of gene methylation during the prenatal developmental period. In this study, we sought to identify loci differentially methylated by maternal smoking during pregnancy and relate their methylation levels to various behavioural and physical outcomes relevant to ADHD.

METHODS

We extracted DNA from blood samples from children diagnosed with ADHD and deeply phenotyped. Genome-wide DNA methylation was assessed using Infinium MethylationEPIC BeadChip. Maternal smoking during pregnancy was self-declared and assessed retrospectively.

RESULTS

Our sample included 231 children with ADHD. Statistically significant differences in DNA methylation between children exposed or not to maternal smoking during pregnancy were detected in 3457 CpGs. We kept 30 CpGs with at least 5% of methylation difference between the 2 groups for further analysis. Six genes were associated with varied phenotypes of clinical relevance to ADHD. The levels of DNA methylation in RUNX1 were positively correlated with the CBCL scores, and DNA methylation in MYO1G correlated positively with the score at the Conners rating scale. Methylation level in a CpG located in GFI1 correlated with birthweight, a risk factor for ADHD. Differentially methylated regions were also identified and confirmed the association of RUNX1 methylation levels with the CBCL score.

LIMITATIONS

The study has several limitations, including the retrospective recall with self-report of maternal smoking during pregnancy as well as the grouping of individuals of varying age and developmental stage and of both males and females. In addition, the correlation design prevents the building of causation models.

CONCLUSION

This study provides evidence for the association between the level of methylation at specific loci and quantitative dimensions highly relevant for ADHD as well as birth weight, a measure that has already been associated with increased risk for ADHD. Our results provide further support to public health educational initiatives to stop maternal smoking during pregnancy.

Estimating the Risk of Attention Deficit Hyperactivity Disorder (ADHD) in Parents of Children with ADHD and the Association with Their Children's Disease Severity and Adherence to Medication

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) is characterised by inattentiveness, hyperactivity, and impulsivity. Up to half of the affected children have a parent with ADHD. In this study, the risk of ADHD among parents of ADHD children was estimated. The associations between parental ADHD and child ADHD severity and medication adherence were determined.

METHODOLOGY

Parents of children and adolescents diagnosed with ADHD attending the University Kebangsaan Malaysia Medical Centre (UKMMC) were recruited between June to August 2022 and the administered Conners' Adult ADHD Rating Scale (CAARS) self-report short form, Vanderbilt ADHD Parent Rating Scale (performance section), and Medication Adherence Report Scale (MARS).

RESULTS

Forty-five children with ADHD were recruited and 15 out of 45 (33%) parents were detected to have ADHD. ADHD severity was worse in children with ADHD parents for total severity (mean of 34.67 vs. 29.13, p = 0.047) and difficult behaviours at home (mean of 7.87 vs. 6.27, p = 0.036). The children's academic performance and behavioural challenges at home and school were positively correlated with the parental ADHD scores for 'inattention' and 'problems with self-care' subscales.

CONCLUSIONS

A total of 33% of ADHD children had parents with ADHD. ADHD children with ADHD parents were more likely to have behavioural problems at home and more severe ADHD. However, no statistical significance was noted with medication adherence.

Examining the relationship between birth weight and attention-deficit hyperactivity disorder diagnosis

Background

Attention-deficit hyperactivity disorder (ADHD) is a neurodevelopmental condition that is prevalent in children worldwide. We evaluated the potential relationship between birth weight and ADHD using newly released data from the National Survey of Children's Health 2019-2020.

Methods

This population-based survey study used parent recollection data that were collected and submitted by 50 states and the District of Columbia to the National Survey of Children's Health database from the National Survey of Children's Health database. Those aged < 3 years and without birth weight or ADHD records were excluded. Children were stratified according to ADHD diagnosis and birth weight: very low birth weight (VLBW, < 1,500 g), low birth weight (LBW, 1,500-2,500 g), and normal birth weight (NBW, ≥ 2,500 g). Multivariable logistic regression was applied to examine the causal association between birth weight and ADHD while controlling for child and household characteristics.

Results

The final sample consisted of 60,358 children, of whom 6,314 (9.0%) were reported to have an ADHD diagnosis. The prevalence of ADHD was 8.7% in NBW children, 11.5% in LBW, and 14.4% in VLBW. Compared with NBW children, LBW children [adjusted odds ratio (aOR), 1.32 (95% CI, 1.03-1.68)], and VLBW children [aOR, 1.51 (95% CI, 1.06-2.15)] had a significantly higher risk of ADHD after adjusting all variables. These associations persisted in the male subgroups.

Conclusion and relevance

This study found that LBW and VLBW children were at a higher risk of ADHD.