Attention Deficit Hyperactivity Disorder Symptoms and Low Educational Achievement: Evidence Supporting A Causal Hypothesis

Healthcare utilization and comorbidity shortly before suicide mortality in patients with attention-deficit/hyperactivity disorder: a nested case-control study

BACKGROUND

Few studies have analyzed healthcare utilization before suicide among individuals with attention-deficit/hyperactivity disorder (ADHD). This study examined the pattern of healthcare utilization and comorbidities shortly before death among patients with ADHD who died by suicide and compared these data with those of living controls. This study used Taiwan's National Health Insurance Research Database to identify patients with ADHD (N = 379,440) between January 1, 2001, and December 31, 2016. Subsequently, the researchers identified 159 suicide decedents by linking each patient with the National Mortality Database. By conducting a nested case-control study with risk-set sampling from the ADHD cohort, the researchers selected 20 age- and sex-matched controls (n = 3180) for each patient who died by suicide (cases). The researchers then applied conditional logistic regression to investigate differences in healthcare utilization as well as psychiatric and physical comorbidities between case patients and controls. Case patients had higher healthcare utilization within 3 months before suicide, particularly in the psychiatry, emergency, internal medicine, neurosurgery, and plastic surgery departments. These patients also had higher risks of psychiatric comorbidities, including schizophrenia, bipolar disorder, depressive disorder, and sleep disorder, as well as physical comorbidities such as hypertension and other forms of heart disease. Among patients with ADHD, suicide decedents had increased healthcare utilization and higher risks of specific psychiatric and physical comorbidities than living controls. Thus, for suicide prevention among individuals with ADHD, suicide risk must be detected early and comorbidities should be adequately managed.

The student-teacher relationship and ADHD symptomatology: A meta-analysis

Children with attention-deficit/hyperactivity disorder (ADHD) typically experience significant academic and social impairments, including problem behaviors in the classroom. Existing research suggests students who present with ADHD symptoms are more likely to have relationships with their teachers that are low in closeness and high in conflict. However, research about the quality of relationships between teachers and students with ADHD symptoms remains quantitatively un-synthesized. The present meta-analysis quantitatively describes the overall quality of student-teacher relationships for children who present with ADHD symptoms according to the relational dimensions of closeness and conflict. Database searches of PsycInfo, ERIC, and ProQuest (theses and dissertations) were conducted to collect a sample of 27 quantitative studies for statistical analyses. A total of 47 effect sizes (N = 17,236) were included in the analyses. Results confirm the trends seen in the literature. Children with symptoms of ADHD tended to have relationships with their teachers that were low in closeness (r = -0.170) and high in conflict (r = 0.414). Additionally, eight moderator analyses were conducted (i.e., grade level, informant types, informant consistency, sample type, reported comorbidity, gender, and ADHD presentation) to assess their effect on the link between ADHD symptoms and student-teacher relationship quality. The results of this meta-analysis provide insight into the quality of relationships that students who exhibit ADHD symptoms form with their teachers also may inform intervention programs that aim to best support students.

Gestational organophosphate ester exposure and preschool attention-deficit/hyperactivity disorder in the Norwegian Mother, Father, and Child cohort study

BACKGROUND

Attention-deficit/hyperactivity-disorder (ADHD) is a leading neurodevelopmental disorder in children worldwide; however, few modifiable risk factors have been identified. Organophosphate esters (OPEs) are ubiquitous chemical compounds that are increasingly prevalent as a replacement for other regulated chemicals. Current research has linked OPEs to neurodevelopmental deficits. The purpose of this study was to assess gestational OPE exposure on clinically-assessed ADHD in children at age 3 years.

METHODS

In this nested case-control study within the Norwegian Mother, Father, and Child Cohort study, we evaluated the impact of OPE exposure at 17 weeks' gestation on preschool-age ADHD. Between 2007 and 2011, 260 ADHD cases were identified using the Preschool Age Psychiatric Assessment and compared to a birth-year-stratified control group of 549 children. We categorized bis(2-butoxyethyl) phosphate (BBOEP) and bis(1,3-dichloro-2-propyl) phosphate (BDCIPP) as values < limit of detection (LOD) (BBOEP N = 386, BDCIPP N = 632), ≥LOD but < limit of quantification (LOQ) (BBOEP N = 413; BDCIPP N = 75), or above LOQ (BBOEP N = 70; BDCIPP N = 102). Diphenyl phosphate (DPhP) and di-n-butyl phosphate (DnBP) were categorized as quartiles and also modeled with a log10 linear term. We estimated multivariable adjusted odds ratios (ORs) using logistic regression and examined modification by sex using an augmented product term approach.

RESULTS

Mothers in the 3rd DnBP quartile had 1.71 times the odds of having a child with ADHD compared to the 1st quartile (95%CI: 1.13, 2.58); a similar trend was observed for log10 DnBP and ADHD. Mothers with BDCIPP ≥ LOD but < LOQ had 1.39 times the odds of having a child with ADHD compared to those with BDCIPP < LOD (95%CI: 0.83, 2.31). Girls had lower odds of ADHD with increasing BBOEP exposure (log10 OR: 0.55 (95%CI: 0.37, 0.93), however boys had a weakly increased odds (log10 OR: 1.25 (95%CI: 0.74, 2.11) p-interaction = 0.01].

CONCLUSIONS

We found modest increased odds of preschool ADHD with higher DnBP and BDCIPP exposure.

Organophosphorus Pesticide Exposure at 17 Weeks' Gestation and Odds of Offspring Attention-Deficit/Hyperactivity Disorder Diagnosis in the Norwegian Mother, Father, and Child Cohort Study

Prenatal organophosphorus pesticides (OPs) are ubiquitous and have been linked to adverse neurodevelopmental outcomes. However, few studies have examined prenatal OPs in relation to diagnosed attention-deficit/hyperactivity disorder (ADHD), with only two studies exploring this relationship in a population primarily exposed through diet. In this study, we used a nested case-control study to evaluate prenatal OP exposure and ADHD diagnosis in the Norwegian Mother, Father, and Child Cohort Study (MoBa). For births that occurred between 2003 and 2008, ADHD diagnoses were obtained from linkage of MoBa participants with the Norwegian Patient Registry (N = 297), and a reference population was randomly selected from the eligible population (N = 552). Maternal urine samples were collected at 17 weeks' gestation and molar sums of diethyl phosphates (ΣDEP) and dimethyl phosphates metabolites (ΣDMP) were calculated. Multivariable adjusted logistic regression models were used to estimate the association between prenatal OP metabolite exposure and child ADHD diagnosis. Additionally, multiplicative effect measure modification (EMM) by child sex was assessed. In most cases, mothers in the second and third tertiles of ΣDMP and ΣDEP exposure had slightly lower odds of having a child with ADHD, although confidence intervals were wide and included the null. EMM by child sex was not observed for either ΣDMP or ΣDEP. In summary, we did not find evidence that OPs at 17 weeks' gestation increased the odds of ADHD in this nested case-control study of ADHD in MoBa, a population primarily experiencing dietary exposure.

Características das prescrições de metilfenidato em ambulatório de neuropediatria

RESUMO O metilfenidato não é disponibilizado pelo Sistema Único de Saúde (SUS), pois não faz parte da Relação Nacional de Medicamentos Essenciais. Todavia, o metilfenidato 10 mg é disponibilizado pela rede pública em Maringá-PR de acordo com a Política da Assistência Farmacêutica do município. Objetivou-se analisar as características das prescrições médicas de metilfenidato para crianças em ambulatório de neuropediatria vinculado ao SUS no município. Estudo transversal observacional retrospectivo de caráter quantitativo, realizado por meio da coleta de dados dos prontuários cadastrados no Sistema Gestor da rede pública de saúde do município, pelo ambulatório de neuropediatria na Unidade Básica de Saúde, Zona 7, entre janeiro de 2017 e novembro de 2019. Analisaram-se os dados por frequência relativa e absoluta. Emitiram-se 339 prescrições pelo neuropediatra responsável do ambulatório para 107 pacientes de 6 a 11 anos. Notou-se distribuição geográfica desigual das crianças atendidas conforme bairro da cidade, o que denota influência socioeconômica na prescrição de medicamentos. Ressaltam-se picos de prescrições coincidindo com o período do ano letivo escolar. Concluiu-se que o acompanhamento especializado adequado é premissa para o tratamento, não dispensando a rede longitudinal de assistência. Ademais, evidencia-se o impacto das condições socioeconômicas, tanto na prescrição como na aquisição do medicamento.

Potential Inflammatory Biomarker in Patients with Attention Deficit Hyperactivity Disorder

Attention deficit hyperactivity disorder (ADHD) is a prevalent neurodevelopmental disorder that can diminish the quality of life of both children and adults in academic, occupational, and social contexts. The kynurenine pathway (KP) contains a set of enzymatic reactions involved in tryptophan (TRP) degradation. It is known to be associated with the risk of developing ADHD. This review will address the KP and underlying mechanism of inflammation in ADHD. Potential inflammatory biomarkers reported in the most recent studies are summarized. Although a strong neuroimmunological basis has been established due to the advances of recent neurobiological research, the pathophysiology of ADHD remains unclear.

Mendelian randomization analysis for attention deficit/hyperactivity disorder: studying a broad range of exposures and outcomes

BACKGROUND

Attention deficit/hyperactivity disorder (ADHD) is a highly prevalent neurodevelopmental disorder caused by a combination of genetic and environmental factors and is often thought as an entry point into a negative life trajectory, including risk for comorbid disorders, poor educational achievement or low income. In the present study, we aimed to clarify the causal relationship between ADHD and a comprehensive range of related traits.

METHODS

We used genome-wide association study (GWAS) summary statistics for ADHD (n = 53 293) and 124 traits related to anthropometry, cognitive function and intelligence, early life exposures, education and employment, lifestyle and environment, longevity, neurological, and psychiatric and mental health or personality and psychosocial factors available in the MR-Base database (16 067 ≤n ≤766 345). To investigate their causal relationship with ADHD, we used two-sample Mendelian randomization (MR) with a range of sensitivity analyses, and validated MR findings using causal analysis using summary effect estimates (CAUSE), aiming to avoid potential false-positive results.

RESULTS

Our findings strengthen previous evidence of a causal effect of ADHD liability on smoking and major depression, and are consistent with a causal effect on odds of decreased average total household income [odds ratio (OR) = 0.966, 95% credible interval (CrI) = (0.954, 0.979)] and increased lifetime number of sexual partners [OR = 1.023, 95% CrI = (1.013, 1.033)]. We also found evidence for a causal effect on ADHD for liability of arm predicted mass and weight [OR = 1.452, 95% CrI = (1.307, 1.614) and OR = 1.430, 95% CrI = (1.326, 1.539), respectively] and time spent watching television [OR = 1.862, 95% CrI = (1.545, 2.246)], and evidence for a bidirectional effect for age of first sexual intercourse [beta = -0.058, 95% CrI = (-0.072, -0.044) and OR = 0.413, 95% CrI = (0.372, 0.457), respectively], odds of decreased age completed full-time education [OR = 0.972, 95% CrI = (0.962, 0.981) and OR = 0.435, 95% CrI = (0.356, 0.533), respectively] and years of schooling [beta = -0.036, 95% CrI = (-0.048, -0.024) and OR = 0.458, 95% CrI = (0.411, 0.511), respectively].

CONCLUSIONS

Our results may contribute to explain part of the widespread co-occurring traits and comorbid disorders across the lifespan of individuals with ADHD and may open new opportunities for developing preventive strategies for ADHD and for negative ADHD trajectories.

Examining the Educational Gap for Children with ADHD and Subthreshold ADHD

OBJECTIVE

The present study examined the impact of Attention Deficit Hyperactivity Disorder (ADHD) on core educational outcomes in two large community cohorts of Australian school children.

METHOD

Academic (reading and numeracy) and non-academic (school engagement, attendance, peer victimization, and parental expectations) outcomes were compared between children with ADHD, subthreshold ADHD, and controls when children were in grade 5 (M age = 10.5). Data were drawn from the Longitudinal Study of Australian Children birth cohort (LSAC; N = 3,540) and the Children's Attention Project (CAP; N = 356).

RESULTS

Both subthreshold ADHD and ADHD groups had poorer outcomes on all measures, with medium effects sizes. Differences were not evident between subthreshold ADHD and ADHD groups.

CONCLUSIONS

Educational outcomes examined in this study highlight the educational risk for upperprimary school children with ADHD or subthreshold ADHD, in comparison to their peers. Monitoring these outcomes is necessary to inform policy, practice, and intervention.

Effect of Vitamin D Supplementation on Inflammatory Biomarkers in School-Aged Children with Attention Deficit Hyperactivity Disorder

METHOD

This randomized double-blind, placebo-controlled trial was conducted on 75 school-aged children with a diagnosis of ADHD based on DSM-V criteria. Children were randomly allocated to receive either vitamin D3 (2000 IU/day) or a placebo for 3 months. Serum IL-6, TNF-α, and 25(OH) D were assessed before and after the intervention to determine the effects of vitamin D on the highlighted parameters.

RESULTS

Serum levels of 25(OH) D increased significantly in the vitamin D group (P=0.01). However, no significant differences in serum IL-6 and TNF-α were found between both groups at the baseline and at the end of the intervention.

CONCLUSION

The findings revealed that vitamin D supplementation for 3 months is not efficacious in reducing inflammatory cytokines in children with ADHD. Further studies are required to confirm these results.

Inflammation, Anxiety, and Stress in Attention-Deficit/Hyperactivity Disorder

Attention-deficit/hyperactivity disorder (ADHD) is a prevalent and serious neurodevelopmental disorder characterized by symptoms of inattention and/or hyperactivity/impulsivity. Chronic and childhood stress is involved in ADHD development, and ADHD is highly comorbid with anxiety. Similarly, inflammatory diseases and a pro-inflammatory state have been associated with ADHD. However, while several works have studied the relationship between peripheral inflammation and stress in affective disorders such as depression or bipolar disorder, fewer have explored this association in ADHD. In this narrative review we synthetize evidence showing an interplay between stress, anxiety, and immune dysregulation in ADHD, and we discuss the implications of a potential disrupted neuroendocrine stress response in ADHD. Moreover, we highlight confounding factors and limitations of existing studies on this topic and critically debate multidirectional hypotheses that either suggest inflammation, stress, or anxiety as a cause in ADHD pathophysiology or inflammation as a consequence of this disease. Untangling these relationships will have diagnostic, therapeutic and prognostic implications for ADHD patients.

Genetic correlates of socio-economic status influence the pattern of shared heritability across mental health traits

Epidemiological studies show high comorbidity between different mental health problems, indicating that individuals with a diagnosis of one disorder are more likely to develop other mental health problems. Genetic studies reveal substantial sharing of genetic factors across mental health traits. However, mental health is also genetically correlated with socio-economic status (SES), and it is therefore important to investigate and disentangle the genetic relationship between mental health and SES. We used summary statistics from large genome-wide association studies (average N ~ 160,000) to estimate the genetic overlap across nine psychiatric disorders and seven substance use traits and explored the genetic influence of three different indicators of SES. Using genomic structural equation modelling, we show significant changes in patterns of genetic correlations after partialling out SES-associated genetic variation. Our approach allows the separation of disease-specific genetic variation and genetic variation shared with SES, thereby improving our understanding of the genetic architecture of mental health.

Genetic correlates of socio-economic status influence the pattern of shared heritability across mental health traits

Epidemiological studies show high comorbidity between different mental health problems, indicating that individuals with a diagnosis of one disorder are more likely to develop other mental health problems. Genetic studies reveal substantial sharing of genetic factors across mental health traits. However, mental health is also genetically correlated with socio-economic status (SES), and it is therefore important to investigate and disentangle the genetic relationship between mental health and SES. We used summary statistics from large genome-wide association studies (average N ~ 160,000) to estimate the genetic overlap across nine psychiatric disorders and seven substance use traits and explored the genetic influence of three different indicators of SES. Using genomic structural equation modelling, we show significant changes in patterns of genetic correlations after partialling out SES-associated genetic variation. Our approach allows the separation of disease-specific genetic variation and genetic variation shared with SES, thereby improving our understanding of the genetic architecture of mental health.

"Real-world" effectiveness of methylphenidate in improving the academic achievement of Attention-Deficit Hyperactivity Disorder diagnosed students-A systematic review

WHAT IS KNOWN AND OBJECTIVE

Attention-deficit hyperactivity disorder (ADHD) symptoms usually impairs academic achievement and can trigger the onset of medication. Methylphenidate is a drug widely prescribed to treat ADHD. However, systematic reviews of randomized clinical trials suggest that it does not lead to great improvements in academic performance. Thus, we aimed to evaluate the evidence on the "real-world" effectiveness of methylphenidate in improving the academic achievement of ADHD students.

METHODS

We conducted a systematic review of observational studies retrieved from five electronic databases, besides a manual search and search in grey literature. Studies evaluating treatment with methylphenidate compared to no treatment or other pharmacological/non-pharmacological alternatives used in ADHD were included. The risk of bias of the selected studies was assessed using adapted versions of the Newcastle-Ottawa Scale.

RESULTS AND DISCUSSION

Nine studies (from ten reports) were included in the review: four cohorts, two before-and-after designs and three cross-sectional studies. They involved 12,269 children and adolescents aged 6-18 years. The doses of methylphenidate ranged from 10 to 72 mg/day, and the duration of the treatment from 2.6 months to 4.25 years. Five of these studies concluded that methylphenidate improves academic performance. However, three of the four lowest-bias risk studies concluded that the drug is ineffective. Five studies assessed the long-term use of methylphenidate, and four of them concluded that it does not result in better outcomes in the school setting. Most included studies had considerable limitations and significant heterogeneity regarding methodological design and academic performance measurement criteria.

WHAT IS NEW AND CONCLUSION

Although some studies indicate that the short-term use of methylphenidate may improve outcomes in the school environment, the available evidence does not support the establishment of adequate conclusions about the real benefits of methylphenidate in the academic improvement of ADHD students.

Notes on Three Decades of Methodology Workshops

Since 1987, a group of behavior geneticists have been teaching an annual methodology workshop on how to use state-of-the-art methods to analyze genetically informative data. In the early years, the focus was on analyzing twin and family data, using information of their known genetic relatedness to infer the role of genetic and environmental factors on phenotypic variation. With the rapid evolution of genotyping and sequencing technology and availability of measured genetic data, new methods to detect genetic variants associated with human traits were developed and became the focus of workshop teaching in alternate years. Over the years, many of the methodological advances in the field of statistical genetics have been direct outgrowths of the workshop, as evidence by the software and methodological publications authored by workshop faculty. We provide data and demographics of workshop attendees and evaluate the impact of the methodology workshops on scientific output in the field by evaluating the number of papers applying specific statistical genetic methodologies authored by individuals who have attended workshops.

ADHD and offending

OBJECTIVES

International studies have reported disproportionately higher rates of Attention Deficit Hyperactivity Disorder (ADHD) among youth and adult offenders across police custody, prison, probation and forensic mental health settings, estimated to fall at around 25%. This review aimed to investigate the presentation and vulnerabilities of this subpopulation of people with ADHD compared to those with ADHD in the general population and consider how this may impact on the approach to assessment and treatment in this population.

METHODOLOGY

A selective review of the extant literature was conducted to investigate how offenders with ADHD may present differently from their non-ADHD peers in their clinical presentation, criminogenic behaviour and psychological vulnerabilities.

RESULTS

Nearly all (around 96%) offenders with ADHD have additional comorbid problems, including mood, anxiety, conduct, substance use and personality disorders. Compared with offenders without ADHD, they become involved in the criminal justice system (CJS) at a younger age, have higher rates of recidivism, are more likely to make a false confession, engage in behavioural disturbances in custody, have health risk behaviours and a lower quality of life. Assessing and treating ADHD in this subpopulation may be more complex due to their presentation.

CONCLUSIONS

Offenders with ADHD are disadvantaged within the system by their ADHD symptoms being unrecognised and/or misunderstood; their diagnosis of ADHD may be missed or misdiagnosed. This is at cost to the individual, from both a health and rehabilitative perspective, as well as more broadly to society.

The female side of pharmacotherapy for ADHD-A systematic literature review

OBJECTIVE

This comprehensive review examined sex differences in prescription rates and efficacy or effectiveness of pharmacotherapy treatment in girls and women with attention deficit hyperactivity disorder (ADHD), while identifying gaps in the scientific knowledge on this topic.

METHOD

A rigorous electronic database search was carried out in order to identify all published studies on female-specific effects of stimulants and non-stimulants in the treatment of ADHD. In total, 2672 studies were screened of which 21 studies (seven on prescription rates, 14 on effects of pharmacotherapy) met the inclusion criteria and were included for analysis.

RESULTS

In all seven studies on ADHD prescription rates, girls received significantly less prescriptions than boys, a difference however no longer seen in adults with the exception of one study. Each of the 14 studies on effectiveness / efficacy found at least one sex-difference in the effects of ADHD pharmacotherapy.

CONCLUSION

Several sex-differences are demonstrated in the prescription, usage and efficacy /effectiveness of both stimulant and non-stimulant ADHD pharmacotherapy. A single daily use of MPH may possibly not be optimal for girls with ADHD and ATX may be a promising medication for girls and women with ADHD. The robustness of this result requires further investigation.

Mechanisms linking parental educational attainment with child ADHD, depression, and academic problems: a study of extended families in The Norwegian Mother, Father and Child Cohort Study

BACKGROUND

Low educational attainment in parents is associated with child psychopathology. It is not clear whether the associations are due to risk factors that family members share or due to effects of maternal or paternal education on the offspring. We investigate whether associations between maternal and paternal educational attainment and child symptoms of attention deficit/hyperactivity disorder (ADHD), depression, and academic problems are due to shared genetic factors, shared family environmental factors, or effects of the parental phenotype educational attainment itself.

METHODS

This study is based on the Norwegian Mother, Father and Child Cohort Study (MoBa). The sample comprised 34,958 children (17,128 girls) in 28,372 extended-family units. We used data from related nuclear families linked by siblings in the parent generation. We applied a quasi-experimental extended children-of-twins design that included siblings in both generations and took account of nonrandom mating by including partners. Educational attainment was self-reported by mothers and fathers. Mothers reported children's symptoms of ADHD, symptoms of depression, and academic problems by questionnaire when the children were 8 years old.

RESULTS

Children of lowly educated parents scored higher on all outcomes and had an approximate doubling of the risk of high symptom levels. The association between maternal and paternal educational attainment and child symptoms of ADHD and academic problems persisted after controlling for shared genetic and family environmental factors. Phenotypic transmission to depression was weaker and in the best fitting model fully explained by genetic factors shared by the two generations.

CONCLUSIONS

Associations between educational attainment of mothers and fathers and child symptoms of ADHD and academic problems could not be ascribed to shared familial risk factors, whereas associations with symptoms of depression could. Parental education or resources and behaviors resulting from low education might be targets of interventions aimed at reducing symptoms of ADHD and academic problems.

Females with ADHD: An expert consensus statement taking a lifespan approach providing guidance for the identification and treatment of attention-deficit/ hyperactivity disorder in girls and women

BACKGROUND

There is evidence to suggest that the broad discrepancy in the ratio of males to females with diagnosed ADHD is due, at least in part, to lack of recognition and/or referral bias in females. Studies suggest that females with ADHD present with differences in their profile of symptoms, comorbidity and associated functioning compared with males. This consensus aims to provide a better understanding of females with ADHD in order to improve recognition and referral. Comprehensive assessment and appropriate treatment is hoped to enhance longer-term clinical outcomes and patient wellbeing for females with ADHD.

METHODS

The United Kingdom ADHD Partnership hosted a meeting of experts to discuss symptom presentation, triggers for referral, assessment, treatment and multi-agency liaison for females with ADHD across the lifespan.

RESULTS

A consensus was reached offering practical guidance to support medical and mental health practitioners working with females with ADHD. The potential challenges of working with this patient group were identified, as well as specific barriers that may hinder recognition. These included symptomatic differences, gender biases, comorbidities and the compensatory strategies that may mask or overshadow underlying symptoms of ADHD. Furthermore, we determined the broader needs of these patients and considered how multi-agency liaison may provide the support to meet them.

CONCLUSIONS

This practical approach based upon expert consensus will inform effective identification, treatment and support of girls and women with ADHD. It is important to move away from the prevalent perspective that ADHD is a behavioural disorder and attend to the more subtle and/or internalised presentation that is common in females. It is essential to adopt a lifespan model of care to support the complex transitions experienced by females that occur in parallel to change in clinical presentation and social circumstances. Treatment with pharmacological and psychological interventions is expected to have a positive impact leading to increased productivity, decreased resource utilization and most importantly, improved long-term outcomes for girls and women.

Adolescent Socioeconomic Status and Mental Health Inequalities in the Netherlands, 2001-2017

Even in wealthy countries there are substantial socioeconomic inequalities in adolescent mental health. Socioeconomic status (SES) indicators-parental SES, adolescent subjective SES and adolescent educational level-are negatively associated with adolescent mental health problems, but little is known about the interplay between these SES indicators and whether associations have changed over time. Using data from the Dutch Health Behaviour in School-Aged Children (HBSC) studies (n = 27,020) between 2001 and 2017, we examined associations between three SES indicators and six indicators of adolescent mental health problems. Linear regressions revealed that adolescent subjective SES and adolescent educational level were independently negatively associated with adolescent mental health problems and positively associated with adolescent life satisfaction, but parental SES had negligible independent associations with adolescent mental health problems and life satisfaction. However, when interactions between SES indicators were considered, high adolescent subjective SES was shown to buffer the negative association between parental SES and adolescent mental health problems and the positive association between parental SES and life satisfaction. Despite societal changes between 2001 and 2017, socioeconomic inequalities in adolescent mental health were stable during this period. Findings suggest that all three SES indicators-parental SES, adolescent subjective SES and adolescent educational level-are important for studying socioeconomic inequalities in adolescent mental health.

Temperament correlates in adult ADHD: A systematic review★★

BACKGROUND

Attention deficit and hyperactivity disorder (ADHD) is the most common neurodevelopmental disorder in children, but adult-ADHD is still an under-diagnosed and untreated condition. Treating adult-ADHD is complex and requires effective strategies for ADHD symptoms and comorbidities. Because of its high comorbidity rate with mood disorders and the growing interest in symptoms of emotional dysregulation in these patients, our aim was to collect studies that investigated temperament correlates in adult people with ADHD, to better understand the association between them and the eventual role of temperament as a prognostic-therapeutic marker.

METHODS

We performed a systematic review of the literature. We included only studies that measured temperament traits in ADHD adults using the Temperament Evaluation of Memphis, Paris and San Diego-Auto-questionnaire (TEMPS-A) or the Temperament and Character Inventory (TCI).

RESULTS

We retrieved 15 papers that used the TCI and 6 papers that used the TEMPS-A. In the TCI studies, ADHD was associated with high scores on Novelty Seeking and Harm Avoidance and low scores on Persistence. For the TEMPS-A studies, ADHD and Bipolar Disorders share some similarities in temperament scores, except for the hyperthymic temperament score.

LIMITATIONS

A comparison between the TCI and TEMPS-A results was not possible. The number of papers included was small. Among them, the type of sample, the number of recruited subjects and the ADHD assessment were very different.

CONCLUSIONS

The majority of ADHD individuals share temperament traits such as lability, irritability and excessiveness of emotional responses. Further research is needed to better understand whether temperament influences the pharmacological response of ADHD patients and whether temperament scores affect the long-term therapeutic outcome.

The developmental course of inattention symptoms predicts academic achievement due to shared genetic aetiology: a longitudinal twin study

Symptoms of attention-deficit hyperactivity disorder, in particular inattention symptoms, are associated with academic achievement. However, whether and why the developmental course of inattention symptoms (i.e. systematic decreases or increases of symptoms with age) predicts academic achievement remains unclear. A total of 5634 twin pairs born in the UK were included in the current study. We used latent growth curve modelling to estimate the baseline level and the developmental course of inattention symptoms (assessed at ages 8, 11, 14 and 16 years) and test whether they predicted the General Certificate of Secondary Education scores (GCSE, at age 16 years). We then implemented multivariate twin modelling to determine the role of genetic and environmental factors in explaining the relationship between inattention symptoms and GCSE scores. Increasing inattention symptoms across childhood and adolescence predicted poorer GCSE scores independently of the baseline level of inattention. Genetic factors explained most of this relationship, i.e. genetic factors contributing to individual differences in the developmental course of inattention also influenced GCSE scores. In conclusion, our study demonstrates that genetic factors underlying the developmental course of inattention symptoms across childhood and adolescence also influence academic achievement. This may result from indirect mechanism, whereby genetic factors explain systematic changes in inattention levels with age, which in turn impact academic achievement. The shared genetic aetiology may also suggest common neurobiological processes underlying both the developmental course of inattention symptoms and academic achievement.