What have we learnt about the causes of ADHD?

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Genetic nurture versus genetic transmission of risk for ADHD traits in the Norwegian Mother, Father and Child Cohort Study

Identifying mechanisms underlying the intergenerational transmission of risk for attention-deficit/hyperactivity disorder (ADHD) traits can inform interventions and provide insights into the role of parents in shaping their children's outcomes. We investigated whether genetic transmission and genetic nurture (environmentally mediated effects) underlie associations between polygenic scores indexing parental risk and protective factors and their offspring's ADHD traits. This birth cohort study included 19,506 genotyped mother-father-offspring trios from the Norwegian Mother, Father and Child Cohort Study. Polygenic scores were calculated for parental factors previously associated with ADHD, including psychopathology, substance use, neuroticism, educational attainment, and cognitive performance. Mothers reported on their 8-year-old children's ADHD traits (n = 9,454 children) using the Parent/Teacher Rating Scale for Disruptive Behaviour Disorders. We found that associations between ADHD maternal and paternal polygenic scores and child ADHD traits decreased significantly when adjusting for the child polygenic score (pΔβ = 9.95 × 10-17 for maternal and pΔβ = 1.48 × 10-14 for paternal estimates), suggesting genetic transmission of ADHD risk. Similar patterns suggesting genetic transmission of risk were observed for smoking, educational attainment, and cognition. The maternal polygenic score for neuroticism remained associated with children's ADHD ratings even after adjusting for the child polygenic score, indicating genetic nurture. There was no robust evidence of genetic nurture for other parental factors. Our findings indicate that the intergenerational transmission of risk for ADHD traits is largely explained by the transmission of genetic variants from parents to offspring rather than by genetic nurture. Observational associations between parental factors and childhood ADHD outcomes should not be interpreted as evidence for predominantly environmentally mediated effects.

Long-term changes in serum levels of lipoproteins in children and adolescents with attention-deficit/hyperactivity disorder (ADHD)

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder affecting approximately 5% of children worldwide. The causal mechanisms of ADHD remain unclear as the aetiology of this disorder seems to be multifactorial. One research field addresses the impact on lipid metabolism and particularly serum lipid fractions on the development of ADHD symptoms. This post hoc analysis aimed to investigate long-term changes in serum levels of lipoproteins in children and adolescents with ADHD and controls. Data of German children and adolescents from the nationwide and representative "Kinder- und Jugendgesundheitssurvey (KiGGS)" study were analysed at baseline and at a ten-year follow-up. At the two time points, participants in the control group were compared with those in the ADHD group, both before and after propensity score matching. Differences in total cholesterol, low-density lipoproteins (LDL), high-density lipoproteins (HDL) and triglycerides were assessed between matched children with and without ADHD. In addition, subgroups with versus without methylphenidate use were compared at both time points. At baseline before matching, there were no significant differences for lipid parameters between participants in the ADHD group (n = 1,219) and the control group (n = 9,741): total cholesterol (Exp(ß) = 0.999, 95%-CI 0.911-1.094, p = .979), LDL (Exp(ß) = 0.967, 95%-CI 0.872-1.071, p = .525), HDL (Exp(ß) = 1.095, 95%-CI 0.899-1.331, p = .366) and triglycerides (Exp(ß) = 1.038, 95%-CI 0.948-1.133, p = .412). Propensity score matching confirmed the non-significant differences between the ADHD and non-ADHD group at baseline. At the 10-year follow-up, n = 571 participants fulfilled complete inclusion criteria, among them 268 subjects were classified as ADHD. The two groups did not significantly differ in lipid fractions, neither cross-sectionally nor with regard to long-term changes. There was also no significant difference between methylphenidate subgroups. In this sample of children and adolescents we could not reveal any significant associations between serum lipid fractions and the diagnosis of ADHD, neither cross-sectionally nor longitudinally; even when methylphenidate use was considered. Thus, further studies using larger sample sizes are required to investigate putative long-term changes in serum lipid fractions related to ADHD.

Use of Medication to Treat Attention-Deficit/Hyperactivity Disorder in Young Children: The Role of Maternal History of Psychotropic Medication Use

We examine whether, among children diagnosed with ADHD, are those whose mothers have a history of psychotropic medication use more likely to treat their ADHD with medication? Children born in Manitoba, Canada from 2000 to 2010 diagnosed with ADHD between their 4th and 8th birthday. Maternal psychotropic medication use was assessed from one year before the child's birth to the child's fourth birthday. Logistic regression models examine the relationship between maternal history of psychotropic medication use and the use of medication to treat ADHD in children. Among the 2384 children diagnosed with ADHD, the rate of ADHD medication use was higher for those whose mother had a history of psychotropic medication use (76.6%) than for those whose mothers did not (72.5%) (OR 1.24, 95% CI 1.03, 1.49). Children whose mothers have a history of psychotropic medication use are more likely to have their ADHD treated with medication.

Gestational thyroid hormone concentrations and risk of attention-deficit hyperactivity disorder in the Norwegian Mother, Father and Child Cohort Study

BACKGROUND

Maternal thyroid function plays an important role in foetal brain development; however, little consensus exists regarding the relationship between normal variability in thyroid hormones and common neurodevelopmental disorders, such as attention-deficit hyperactivity disorder (ADHD).

OBJECTIVE

We sought to examine the association between mid-pregnancy maternal thyroid function and risk of clinically diagnosed ADHD in offspring.

METHODS

We conducted a nested case-control study in the Norwegian Mother, Father and Child Cohort Study. Among children born 2003 or later, we randomly sampled singleton ADHD cases obtained through linkage with the Norwegian Patient Registry (n = 298) and 554 controls. Concentrations of maternal triiodothyronine (T3), thyroxine (T4), T3-Uptake, thyroid-stimulating hormone (TSH) and thyroid peroxidase antibody (TPO-Ab) were measured in maternal plasma, collected at approximately 17 weeks' gestation. Indices of free T4 (FT4i) and free T3 (FT3i) were calculated. We used multivariable adjusted logistic regression to calculate odds ratios and accounted for missing covariate data using multiple imputation. We used restricted cubic splines to assess non-linear trends and provide flexible representations. We examined effect measure modification by dietary iodine and selenium intake. In sensitivity analyses, we excluded women with clinically significant thyroid disorders (n = 73).

RESULTS

High maternal T3 was associated with increased risk of ADHD (5th vs 1st quintile odds ratio  2.27, 95% confidence interval 1.21, 4.26). For FT4i, both the lowest and highest quintiles were associated with an approximate 1.6-fold increase in risk of ADHD, with similar trends found for T4. The FT4i association was modified by dietary iodine intake such that the highest risk strata were confined to the low intake group.

CONCLUSIONS

Both high and low concentrations of maternal thyroid hormones, although within population reference ranges, increase the risk of ADHD in offspring. Increased susceptibility may be found among women with low dietary intake of iodine and selenium.

Thrsp Gene and the ADHD Predominantly Inattentive Presentation

There are three presentations of attention-deficit/hyperactivity disorder (ADHD): the predominantly inattention (ADHD-PI), predominantly hyperactive-impulsive (ADHD-HI), and combined (ADHD-C) presentations of ADHD. These may represent distinct childhood-onset neurobehavioral disorders with separate etiologies. ADHD diagnoses are behaviorally based, so investigations into potential etiologies should be founded on behavior. Animal models of ADHD demonstrate face, predictive, and construct validity when they accurately reproduce elements of the symptoms, etiology, biochemistry, and disorder treatment. Spontaneously hypertensive rats (SHR/NCrl) fulfill many validation criteria and compare well with clinical cases of ADHD-C. Compounding the difficulty of selecting an ideal model to study specific presentations of ADHD is a simple fact that our knowledge regarding ADHD neurobiology is insufficient. Accordingly, the current review has explored a potential animal model for a specific presentation, ADHD-PI, with acceptable face, predictive, and construct validity. The Thrsp gene could be a biomarker for ADHD-PI presentation, and THRSP OE mice could represent an animal model for studying this distinct ADHD presentation.

Association between previous abortion history and risk of autism spectrum disorders among offspring: a meta-analysis

BACKGROUND

Previous studies have been showed an association between previous abortion history and risk of Autism spectrum disorders (ASD). However, there is still controversy about true effect estimate of the association.

PURPOSE

This meta-analysis aimed to evaluate the association between previous abortion history and the risk of ASD.

METHODS

A systematic search was performed using PubMed, Scopus, and Web of Sciences databases to identify potential studies published until December 2021. The presence of statistical heterogeneity was determined using the I2 value. In the case of substantial heterogeneity, the random-effects model meta-analysis was used to estimate the pooled relative risks. The publication bias was assessed using the Egger and Begg tests.

RESULTS

Thirteen studies with a total of 331,779 children remained in the present meta-analysis. The estimated odds ratio of the risk of ASD associated with previous abortion history was 1.64 (95% confidence interval [CI], 1.28-2.0; I2=61.7%) in adjusted studies and 1.10 (95% CI, 1.01-1.20; I2=0.0%) in crude studies, based on the random effect model. There was moderate heterogeneity in adjusted studies. The p values for Egger and Begg regression among children with ASD were 0.393 and 0.056, respectively.

CONCLUSION

This meta-analysis suggests that children born from mothers with a history of previous abortion have an increased risk of development of ASD compared to children of mothers without a history of previous abortion.

Association between maternal polycystic ovary syndrome and attention-deficit/hyperactivity disorder in offspring aged 3-6 years: A Chinese population-based study

Background

Maternal polycystic ovary syndrome (PCOS) may increase the risk of attention-deficit/hyperactivity disorder (ADHD) in offspring; however, their association remains unexplored in Asian populations. Hence, this study aimed to investigate the association between maternal PCOS and ADHD in offspring aged 3-6 years and whether it differed by offspring sex.

Methods

This was a district-wide population-based study of 87,081 preschoolers from 234 kindergartens in Longhua District, Shenzhen, China. The parents were invited to complete a self-administrated questionnaire covering information on socio-demographics, maternal disease history, and child behavior. ADHD symptoms were measured with the parent-rating 26-item Swanson, Nolan, and Pelham Rating Scale (SNAP-IV). Logistic regression was performed to examine the associations between maternal PCOS and ADHD symptoms in offspring.

Results

The response rate was 80% and 63,390 mother-child pairs were included. Of the mothers, 1,667 (2.6%) reported PCOS diagnoses. The mean age of children at ADHD assessment was 4.86 ± 0.84[SD] years, and 53.6% were boys. Children with maternal PCOS had a higher risk of developing ADHD symptoms than other children (12.0 vs. 9.4%, adjusted odds ratio [OR] = 1.32, 95% CI: 1.13-1.54). The risk estimate was significant in boys (adjusted OR = 1.38, 95% CI: 1.14-1.66) but not in girls (adjusted OR = 1.23, 95% CI: 0.94-1.57, P for interaction = 0.391). Treatment of PCOS tended to be associated with a lower risk of ADHD symptoms than untreated PCOS albeit risk confidence intervals were overlapped (treated: adjusted OR = 1.28, 95% CI: 1.06-1.54 vs. untreated: adjusted OR = 1.14, 95% CI: 1.08-1.83).

Conclusion

Maternal PCOS increases the risk of developing ADHD in offspring, especially boys. Further studies are warranted to confirm our findings, and early neurodevelopmental screening may be needed in children born to mothers with PCOS.

An overview on neurobiology and therapeutics of attention-deficit/hyperactivity disorder

Attention-Deficit/Hyperactivity Disorder (ADHD) is a prevalent psychiatric condition characterized by developmentally inappropriate symptoms of inattention and/or hyperactivity/impulsivity, which leads to impairments in the social, academic, and professional contexts. ADHD diagnosis relies solely on clinical assessment based on symptom evaluation and is sometimes challenging due to the substantial heterogeneity of the disorder in terms of clinical and pathophysiological aspects. Despite the difficulties imposed by the high complexity of ADHD etiology, the growing body of research and technological advances provide good perspectives for understanding the neurobiology of the disorder. Such knowledge is essential to refining diagnosis and identifying new therapeutic options to optimize treatment outcomes and associated impairments, leading to improvements in all domains of patient care. This review is intended to be an updated outline that addresses the etiological and neurobiological aspects of ADHD and its treatment, considering the impact of the "omics" era on disentangling the multifactorial architecture of ADHD.

The role of psychosocial adversity in the aetiology and course of attention deficit hyperactivity disorder

INTRODUCTION

Attention deficit/hyperactivity disorder (ADHD) has genetic and environmental aetiological factors. There are few publications on the environmental factors. The objective of this review is to present the role of psychosocial adversity in the aetiology and course of ADHD.

METHODS

A search was carried out in the following databases: PubMed, ScienceDirect, SciELO, ClinicalKey, EMBASE, Lilacs, OVID, APA and PsycNET. English and Spanish were selected without being limited by type of study or year of publication. Finally, a qualitative synthesis was conducted.

RESULTS

ADHD development could be related to exposure to adverse factors in the family, school or social environment. It has been proposed as an explanatory mechanism that adversity interacts with genetic variants and leads to neurobiological changes. There may also be a gene-environment correlation whereby individual hereditary characteristics increase the risk of exposure to adversity, and indirectly increase the probability of developing ADHD. Research on psychosocial adversity represents a big challenge, not only due to the complexity of its construct, but also to the effect of subjective perception of a given event.

CONCLUSIONS

ADHD aetiology is complex and involves the interaction of both genetic and environmental factors, in which these factors correlate and cause the disorder. The study of the role of psychosocial adversity in ADHD is fundamental, but it remains a task that entails great difficulties.

Familial Factors Associated With Symptom Severity in Children and Adolescents With ADHD: A Meta-Analysis and Supplemental Review

OBJECTIVE

Both genetic and environmental factors contribute to the development of ADHD, but associations between risk factors and ADHD symptom severity in affected children remain unclear. This systematic review and meta-analysis synthesizes evidence on the association between familial factors and symptom severity in children with ADHD (PROSPERO CRD42020076440).

METHOD

PubMed and PsycINFO were searched for eligible studies.

RESULTS

Forty-three studies (N = 11,123 participants) were meta-analyzed. Five additional studies (N = 2,643 participants) were considered in the supplemental review. Parenting stress (r = .25), negative parenting practices (r = .19), broken parental partnership (r = .19), critical life events (r = .17), parental psychopathologies (r = .14-.16), socioeconomic status (r = -.10), and single-parent family (r = .10) were significantly associated with ADHD symptom severity.

CONCLUSION

These results suggest that psychosocial familial factors show small but significant associations with symptom severity in children with ADHD. Implications are discussed.

Explaining the Association Between Fetal Growth and Childhood ADHD Symptoms: Cross-cohort Replication

The association between restricted fetal growth and symptoms of attention deficit/hyperactivity disorder (ADHD) in childhood is well-replicated and robust. However, fetal growth is determined by many prenatal factors and associations with mental health may be confounded by familial and social context. In this study, we sought to quantify the relative contributions of prenatal factors and familial confounds to the association between fetal growth and ADHD symptoms. Two independent cohorts were analyzed, the Adolescent Brain Cognitive Development study (ABCD; United States) and the Growing Up in Ireland (GUI) study. ADHD symptoms were measured by the Child Behavior Checklist (ABCD) and the Strengths & Difficulties questionnaire (GUI) at age 9-10. Using sequential regression models, we assessed the change-in-association between fetal growth and ADHD symptoms after controlling for sex, familial factors (socioeconomic/demographic factors & family psychiatric history) and prenatal factors (pregnancy complications & maternal substance-use during pregnancy). Converging findings from cohorts suggested that over a quarter of the association between fetal growth and ADHD symptoms is attributable to familial confounds. The degree to which the association was explained by prenatal factors differed by cohort-pregnancy complications explained a larger proportion of the effect in ABCD (7.9%) than GUI (2.7%), and maternal substance-use explained a larger proportion of the effect in GUI (22.7%) compared to ABCD (4.8%). Different explanations of the fetal growth-ADHD association across cohorts suggests cohort-specific, and potentially nationally-specific, risk factors for fetal growth and related neurodevelopmental outcomes. The evidence suggests early prevention of ADHD in Ireland should focus on minimizing maternal smoking during pregnancy. In the US, prevention and treatment of pregnancy complications are highlighted as viable targets for intervention.

Ambivalent bonds, positive and negative emotions, and expectations in teachers’ perceptions of relationship with their students with ADHD

A growing body of research has been focusing recently on the life and well-being of students with attention-deficit/hyperactivity disorder (ADHD) and also on the well-being of their teachers. However, there is a need for in-depth, qualitative insights into ADHD issues from the teachers’ perspectives. Therefore, the main aim of this qualitative study was to use thematic analysis to explore how teachers perceive the relationship with students with ADHD and the factors that influence the quality of this relationship. Sixteen teachers working with adolescent ADHD students were interviewed for this purpose. The results indicate that the quality of the teacher-ADHD student relationship is associated with the ADHD students related behaviours, ambivalent emotions of the teacher, the teacher’s beliefs about ADHD and the beliefs about the determinants of the behaviour of the students with ADHD and the teacher’s approaches and methods of work in the classroom. Furthermore, the results suggest that increasing the quality of the teachers’ well-being is associated with knowledge of ADHD determinants, regulation of ambivalent emotions, empathy, teachers’ ability to perceive positive qualities and the potentials of the students with ADHD and their motivation to teach ADHD students.

ADHD and reification: Four ways a psychiatric construct is portrayed as a disease

Introduction

The descriptive classification Attention-Deficit/Hyperactivity Disorder (ADHD) is often mistaken for a disease entity that explains the causes of inattentive and hyperactive behaviors, rather than merely describing the existence of such behaviors. The present study examines discourse on ADHD to analyze how authors passively and actively contribute to reification-a fallacy in which a concept is represented as a thing existing on its own.

Methods

Critical Discourse Analysis and Qualitative Content Analysis of academic textbooks, scientific articles, websites and videos were used to analyze how ADHD is reified.

Results

The analyses reveal four ways in which inattentive and restless behaviors are presented as an entity by means of the ADHD classification: language choice, logical fallacies, genetic reductionism, and textual silence. First, language choice, such as medical jargon and metaphors aid in representing ADHD as a disease entity. Second, several logical fallacies do the same, including the relatively unknown "ecological fallacy" that refers to the erroneous belief that average group findings, such as average brain size of groups of those with an ADHD classification, can be applied on an individual level. Third, genetic reductionism is often achieved by overstating the results of twin studies and being silent about the disappointing molecular genetic research. Such textual silence is the last identified mechanism of reification and includes instances in which societal factors that affect the ADHD construct are often omitted from texts, thereby obscuring the extent to which ADHD is a limited heuristic.

Discussion

It is essential that discourse communities do not repeat these four ways of reifying behavior and social relations into an alleged entity with the acronym ADHD. The errors and habits of writing may be epistemologically violent by influencing how laypeople and professionals see children and ultimately how children may come to see themselves in a negative way. Beyond that, if the institutional world shaped to help children is based on misguided assumptions, it may cause them harm and help perpetuate the misguided narrative. To counter the dominant, reifying and medicalizing view, guidelines such as the recently published "Dutch ADHD Psychoeducation Guidelines" might be helpful.