Relative age and ADHD symptoms, diagnosis and medication: a systematic review

A systematic review on the application of machine learning models in psychometric questionnaires for the diagnosis of attention deficit hyperactivity disorder

Attention deficit hyperactivity disorder is one of the most prevalent neurodevelopmental disorders worldwide. Recent studies show that machine learning has great potential for the diagnosis of attention deficit hyperactivity disorder. The aim of the present article is to systematically review the scientific literature on machine learning studies for the diagnosis of attention deficit hyperactivity disorder, focusing on psychometric questionnaire tools. The Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines were adopted. The review protocol was registered in the PROSPERO database. A search was conducted in three databases-Web of Science Core Collection, Scopus and Pubmed-with the aim of identifying studies that apply ML techniques to support the diagnosis of attention deficit hyperactivity disorder. A total of 17 empirical studies were found that met the established inclusion criteria. The results showed that machine learning can be used to increase the accuracy of attention deficit hyperactivity disorder diagnosis. Machine learning techniques are useful and effective strategies that can complement traditional diagnostics in patients with attention deficit hyperactivity disorder.

Systematic review and meta-analysis: relative age in attention-deficit/ hyperactivity disorder and autism spectrum disorder

Youngest students in their class, with birthdates just before the school entry cut-off date, are overrepresented among children receiving an Attention-Deficit/Hyperactivity Disorder (ADHD) diagnosis or medication for this. This is known as the relative age effect. This systematic review and meta-analysis summarises the evidence on the influence of relative age on ADHD symptoms, diagnosis and medication prescribing. As no review to date has investigated the association with autism spectrum disorder (ASD) diagnosis, this is also examined. Following prospective registration with PROSPERO, we conducted a systematic review according to the PRISMA guidelines. We searched seven databases: Medline, Embase, PsycInfo, Web of Science Core Collection, ERIC, Psychology and Behavioural Sciences Collection, and Cochrane Library. Additional references were identified from manual search of retrieved reviews. We performed a meta-analysis of quantitative data. Thirty-two studies were included, thirty-one investigated ADHD and two ASD. Younger relative age was associated with ADHD diagnosis and medication, with relative risks of 1.38 (1.36-1.52 95% CI) and 1.28 (1.21-1.36 95% CI) respectively. However, risk estimates exhibited high heterogeneity. A relative age effect was observed for teacher ratings of ADHD symptoms but not for parent ratings. With regard to ASD, the youngest children in their school year were more likely to be diagnosed with ASD. This review confirms a relative age effect for ADHD diagnosis and prescribed ADHD medication and suggests that differences in teacher and parent ratings might contribute to this. Further research is needed on the possible association with ASD.

Association between relative age at school and persistence of ADHD in prospective studies: an individual participant data meta-analysis

BACKGROUND

The youngest children in a school class are more likely than the oldest to be diagnosed with ADHD, but this relative age effect is less frequent in older than in younger school-grade children. However, no study has explored the association between relative age and the persistence of ADHD diagnosis at older ages. We aimed to quantify the association between relative age and persistence of ADHD at older ages.

METHODS

For this meta-analysis, we searched MEDLINE, Embase, CINAHL, PsycINFO, and PubPsych up to April 1, 2022, with terms related to "cohort" and "ADHD" with no date, publication type, or language restrictions. We gathered individual participant data from prospective cohorts that included at least ten children identified with ADHD before age 10 years. ADHD was defined by either a clinical diagnosis or symptoms exceeding clinical cutoffs. Relative age was recorded as the month of birth in relation to the school-entry cutoff date. Study authors were invited to share raw data or to apply a script to analyse data locally and generate anonymised results. Our outcome was ADHD status at a diagnostic reassessment, conducted at least 4 years after the initial assessment and after age 10 years. No information on sex, gender, or ethnicity was collected. We did a two-stage random-effects individual participant data meta-analysis to assess the association of relative age with persistence of ADHD at follow-up. This study was registered with PROSPERO, CRD42020212650.

FINDINGS

Of 33 119 studies generated by our search, we identified 130 eligible unique studies and were able to gather individual participant data from 57 prospective studies following up 6504 children with ADHD. After exclusion of 16 studies in regions with a flexible school entry system that did not allow confident linkage of birthdate to relative age, the primary analysis included 41 studies in 15 countries following up 4708 children for a period of 4 to 33 years. We found that younger relative age was not statistically significantly associated with ADHD persistence at follow-up (odds ratio 1·02, 95% CI 0·99-1·06; p=0·19). We observed statistically significant heterogeneity in our model (Q=75·82, p=0·0011, I2=45%). Participant-level sensitivity analyses showed similar results in cohorts with a robust relative age effect at baseline and when restricting to cohorts involving children with a clinical diagnosis of ADHD or with a follow-up duration of more than 10 years.

INTERPRETATION

The diagnosis of ADHD in younger children in a class is no more likely to be disconfirmed over time than that of older children in the class. One interpretation is that the relative age effect decreases the likelihood of children of older relative age receiving a diagnosis of ADHD, and another is that assigning a diagnostic label of ADHD leads to unexplored carryover effects of the initial diagnosis that persist over time. Future studies should be conducted to explore these interpretations further.

FUNDING

None.

Quantifying Potential Bias Resulting From Child Age on Screening for Hyperactive/Impulsive Presentations of ADHD

OBJECTIVE

This study aims to quantify the potential age bias in screening of hyperactive/impulsive presentations of ADHD in children ages 5 to 12 through comparison of age-based and overall percentiles in screening.

METHOD

A referred clinical sample of 307 children ages 5 to 12 with behavioral concerns completed the Vanderbilt Attention Deficit-Hyperactivity Disorder Diagnostic Parent Rating Scale (VADPRS) and were formally evaluated for ADHD with a diagnostic interview. Analysis utilizing logistic regression and receiver operating characteristic (ROC) curves was performed to compare the screening performance of agebased and overall percentiles.

RESULTS

The age-based percentiles demonstrated no improvement in the analyzed models compared to overall percentiles in hyperactive presentation ADHD screening. This finding was present in the overall sample and in the sub analysis of the 5 to 6 year old children.

CONCLUSIONS

This study identifies no improvement in modeling of hyperactive/impulsive ADHD screening when considering a child's age using age-based percentiles.

Sociodemographic Disparities in Attention-Deficit/Hyperactivity Disorder Overdiagnosis and Overtreatment During Elementary School

Attention-deficit/hyperactivity disorder (ADHD) overdiagnosis and overtreatment unnecessarily exposes children to potential harm and contributes to provider and community skepticism toward those with moderate or severe symptoms and significant impairments, resulting in less supportive care. Yet, which sociodemographic groups of children are overdiagnosed and overtreated for ADHD is poorly understood. We conducted descriptive and logistic regression analyses of a population-based subsample of 1,070 U.S. elementary schoolchildren who had displayed above-average levels of independently assessed behavioral, academic, or executive functioning the year prior to their initial ADHD diagnoses and who did not have prior diagnostic histories. Among these children, (a) 27% of White children versus 19% of non-White children were later diagnosed with ADHD and (b) 20% of White children versus 14% of non-White children were later using medication. In adjusted analyses, White children are more likely to later be diagnosed (odds ratio [OR] range = 1.70-2.62) and using medication (OR range = 1.70-2.37) among those whose prior behavioral, academic, and executive functioning suggested that they were unlikely to have ADHD.

Increased diagnosis of attention-deficit hyperactivity disorder despite stable hyperactive/inattentive behaviours: evidence from two birth cohorts of Australian children

BACKGROUND

Globally, ADHD diagnoses have increased substantially and there is concern that this trend does not necessarily reflect improved detection of cases but that overdiagnosis may be occurring. We directly compared ADHD diagnoses with ADHD-related behaviours and looked for changes across time among Australian children in a large, population-based prospective cohort study.

METHODS

We conducted a secondary analysis of the Longitudinal Study of Australian Children, including 4,699 children born 1999/2000 (cohort 1) and 4,425 children born 2003/2004 (cohort 2), followed from 4 to 13 years of age. We compared pre-diagnosis parent-reported hyperactive/inattentive behaviour scores between newly diagnosed (incident cases) and undiagnosed children and fitted Cox's proportional hazards regression models to examine the relationship between birth cohorts 1 and 2 and the risk of incident ADHD diagnosis.

RESULTS

Cumulative incident ADHD diagnoses increased from 4.6% in cohort 1 (born in 1999/2000) to 5.6% in cohort 2 (born in 2003/2004), while hyperactive/inattentive behaviour scores remained steady. Among ADHD diagnosed children, 26.5% (88/334) recorded pre-diagnosis behaviours in the normal range, 27.6% (n = 92) had borderline scores and 45.8% (n = 153) scored within the clinical range. Children born in 2003/2004 were more likely to be diagnosed with ADHD compared with those born in 1999/2000 (aHR = 1.33, 95% CI = 1.06-1.67, p = .012), regardless of their ADHD behaviour score (p = .972).

CONCLUSIONS

Diagnostic increases were not driven by rises in hyperactive/inattentive behaviours. A quarter of all children with an ADHD diagnosis recorded pre-diagnosis behaviours within the normal range. The increased likelihood of being diagnosed with ADHD for children from the later birth cohort was observed for children across the full range of ADHD-related behaviours.

The effect of school-entry age on health is understudied in low- and middle-income countries: A scoping review and future directions for research

Background

Substantive literature has assessed the impact of starting school at younger ages relative to peers on health in high-income countries (HICs), but there is little evidence from low- and middle-income countries (LMICs). Conclusions drawn from HICs may not apply to different education contexts and health threats. This study maps the empirical evidence on the effect of school-entry age on health in LMICs and identifies directions for future research.

Methods

We conducted a scoping review between August and September 2022 by systematically searching the health sciences, education, economics, psychology, and general sciences literature and included quantitative and qualitative studies. The exposure of interest was relative age for grade defined as starting or progressing through school at a younger or older age compared to peers who are in the same grade. We extracted key characteristics of included studies and summarized their findings. We categorized results into broad health domains which emerged a posteriori from our analyses of included studies, including neurodevelopment and mental health, sexual and reproductive health, non-communicable diseases, and nutrition.

Findings

We identified 8 studies from middle-income countries published between 2017 and 2022. Among those studies, we identified 3 quasi-experimental studies using data from Brazil, Mexico, and Vietnam, and 5 observational studies primarily from Türkiye. Children starting school earlier had an increased risk of being diagnosed with attention deficit hyperactivity disorder, earlier sexual debut and cohabitation, adolescent pregnancy, adolescent marriage, and engaged more frequently in risky behavior compared to children who started school later. Pregnant women who started school younger also had fewer prenatal care visits and experienced more pregnancy complications. Although most studies identified negative health consequences from starting school earlier, the evidence for nutritional outcomes, such as overweight and stunting, was mixed. No studies were identified from low-income countries.

Conclusions

Little is known about the health consequences of school-entry age in low-resource settings. Additional research is needed to investigate the impact of relative age for grade, whether and how these effects persist into adulthood, and to inform strategies that can offset potential disadvantages stemming from school-entry cut-off dates.

Relative age in the school year and risk of mental health problems in childhood, adolescence and young adulthood

PURPOSE

Relative age within the school year ('relative age') is associated with increased rates of symptoms and diagnoses of mental health disorders, including ADHD. We aimed to investigate how relative age influences mental health and behaviour before, during and after school (age range: 4-25 years).

METHOD

We used a regression discontinuity design to examine the effect of relative age on risk of mental health problems using data from a large UK population-based cohort (Avon Longitudinal Study of Parents and Children (ALSPAC); N = 14,643). We compared risk of mental health problems between ages 4 and 25 years using the parent-rated Strengths and Difficulties Questionnaire (SDQ), and depression using self-rated and parent-rated Short Mood and Feelings Questionnaire (SMFQ) by relative age.

RESULTS

The youngest children in the school year have greater parent-rated risk of mental health problems, measured using parent-rated SDQ total difficulties scores. We found no evidence of differences before school entry [estimated standardised mean difference (SMD) between those born on 31 August and 1 September: .02 (-.05, .08)]. We found that estimates of effect size for a 1-year difference in relative age were greatest at 11 years [SMD: .22 (.15, .29)], but attenuated to the null at 25 years [SMD: -.02 (-.11, .07)]. We did not find consistent evidence of differences in self-rated and parent-rated depression by relative age.

CONCLUSIONS

Younger relative age is associated with poorer parent-rated general mental health, but not symptoms of depression.

The Mediatory Role of Executive Functioning on the Association Between Sleep and Both Everyday Memory and ADHD Symptoms in Children and Youth With Down Syndrome

People with Down syndrome (DS) commonly experience challenges with sleep, executive functioning, everyday memory, and symptoms of attention deficit hyperactivity disorder (ADHD). A path analysis was conducted to determine if executive function mediated the relationship between sleep problems and both everyday memory and ADHD symptoms. Parents of 96 children and youth with DS completed questionnaires related to sleep, executive functioning, everyday memory, and ADHD symptoms. Results showed that executive functioning fully mediated the relation between sleep and both everyday memory and ADHD symptoms. Implications for education and intervention for children and youth with DS are discussed.

Environmental pollution and attention deficit hyperactivity disorder: A meta-analysis of cohort studies

There is already knowledge of the extensive risk factors for attention deficit hyperactivity disorder (ADHD) and recent studies suggest that environmental pollution may contribute to an increase in the incidence of the disorder. The aim of our study was to perform a systematic review and meta-analysis of the risk of ADHD in people younger than 18 years old after exposure to environmental pollution. We searched the MEDLINE, Embase, SciELO, CINAHL, LILACS, Cochrane Central, and Web of Science databases and investigated the grey literature from inception until May 31, 2021. All cohort studies that provided data on exposure to environmental pollutants and ADHD in children and adolescents aged from zero to 18 years old were included. Two reviewers independently selected the studies and applied the quality criteria. If there was a divergence, a third reviewer contributed to the final decision. For the meta-analysis, risk ratios and their confidence intervals were calculated with the MetaXL 5.3 program, using the random effects model. In total, 21 articles were included in this systematic review, and 18 studies met the criteria for the meta-analysis, involving 134,619 participants. The meta-analysis suggested that children exposed to higher levels of heavy metal (RR: 2.41, 95% CI: 1.49-3.90), with low heterogeneity (I² = 39%), and lead (RR: 2.37, 95% CI: 1.28-4.40), with moderate heterogeneity (I² = 54%), are at greater risk of developing ADHD than those exposed to lower levels. This meta-analysis suggests that children exposed to higher levels of lead and heavy metal pollution are at greater risk of developing ADHD than those exposed to lower levels.

Relative Age and Psychotropic Drug Use in Preterm and Term-Born Children and Young Adults

BACKGROUND AND OBJECTIVES

Being among the youngest within a school class is linked to disadvantages in various educational and mental health domains. This study aimed to investigate whether preterm born infants are particularly vulnerable to relative age effects on mental health, not previously studied.

METHODS

We used registry data on all Norwegians born between 1989 and 1998 to compare prescription status for psychostimulants, antidepressants, hypnotics, anxiolytics, and antipsychotics per year from age 10 to 23 years (2004-2016) between exposure groups with different time of birth in the year (relative age) and different gestational age (preterm versus term).

RESULTS

Of 488 470 individuals, 29 657 (6,1%) were born preterm. For term born in November/December, the adjusted odds ratio (aORs) for psychostimulant prescription compared with peers born in January/February was 1.80 (95% confidence interval [CI], 1.69-1.91) at ages 10 to 14 years, and 1.17 (95% CI, 1.08-1.27) at ages 20 to 23 years. Within preterm born, the corresponding results were 1.39 (95% CI, 1.13-1.69) and 1.34 (95% CI, 1,00-1.78) at ages 10 through 14 and 20 through 23 years, respectively.

CONCLUSIONS

Being relatively young within the school group was associated with increased psychostimulant prescription in the preterm as well as the term population. In contrast to term peers, the relative age effect for psychostimulant prescription seemed to persist to young adulthood for the preterm population. The results suggest that preterm individuals are vulnerable to long-term effects of relative immaturity and that they require careful consideration from both health care professionals and the school system.

Biological Predictors of Treatment Response in Adult Attention Deficit Hyperactivity Disorder (ADHD): A Systematic Review

Background: Attention-deficit/hyperactivity disorder (ADHD) is a highly prevalent condition with onset in childhood and in many cases persisting into adulthood. Even though an increasing number of studies have investigated the efficacy of pharmacotherapy in the management of adult ADHD, few authors have tried to identify the biological predictors of treatment response. Objectives: To summarize the available data about the biological markers of treatment response in adults affected by ADHD. Methods: A search on the main biomedical and psychological archives (PubMed, Embase, Scopus, and PsycINFO) was performed. Manuscripts in English, published up to May 2022 and having the biological predictors of treatment response in adults with ADHD as their main topic, were included. Results: A total of 3855 articles was screened. Twenty-two articles were finally included. Most of the manuscripts studied neuroimaging and electrophysiological factors as potential predictors of treatment response in adult ADHD patients. No reliable markers were identified until now. Promising findings on this topic regard genetic polymorphisms in snap receptor (SNARE) proteins and default mode network-striatum connectivity. Conclusions: Even though some biological markers seem promising for the prediction of treatment response in adults affected by ADHD, further studies are needed to confirm the available data in the context of precision medicine.

Functional Brain Network Classification Based on Deep Graph Hashing Learning

Brain network classification using resting-state functional magnetic resonance imaging (rs-fMRI) is an effective analytical method for diagnosing brain diseases. In recent years, brain network classification methods based on deep learning have attracted increasing attention. However, these methods only consider the spatial topological characteristics of the brain network but ignore its proximity relationships in semantic space. To overcome this problem, we propose a novel brain network classification method based on deep graph hashing learning named BNC-DGHL. Specifically, we first extract the deep features of the brain network and then learn a graph hash function based on clinical phenotype labels and the similarity of diagnostic labels. Secondly, we use the learned graph hash function to convert deep features into hash codes, which can maintain the original semantic spatial relationships. Finally, we calculate the distance between hash codes to obtain the predicted category of the brain network. Experimental results on ABIDE I, ABIDE II, and ADHD-200 datasets demonstrate that our method achieves better classification performance of brain diseases compared with some state-of-the-art methods, and the abnormal functional connectivities between brain regions identified may serve as biomarkers associated with related brain diseases.

Effect of relative age on diagnosis of autism spectrum disorder in children: a nationwide study in Taiwan

BACKGROUND

The annual cut-off birthdate for entry into school in Taiwan is August 31. Thus, children and adolescents born in August are typically the youngest in their grades. The potential effect of relative age on the diagnosis of autism spectrum disorder (ASD) remains uncertain.

METHODS

A total of 9,548,393 individuals aged 3-17 years during the study period (from September 1, 2001, to August 31, 2011) identified from the Taiwan National Health Insurance Research Database were enrolled into our study. Logistic regression analysis was used to examine the likelihood of receiving ASD diagnosis for those who were born in August (the youngest) compared with those who were born in September (the oldest).

RESULTS

Both boys and girls born in August had a higher likelihood of being diagnosed with ASD (odds ratio [OR]: 1.24, 95% confidence interval [CI]: 1.16-1.32; OR: 1.23, 95% CI 1.06-1.42) than did those born in September. Sensitivity analysis conducted over different periods revealed consistent findings.

DISCUSSION

Relative age, as an indicator of neurocognitive maturity, is a crucial contributor to the risk of being diagnosed with ASD among children and adolescents. Our findings highlight the importance of considering the age of a child within a grade when diagnosing ASD.

Children's Relative Age and Medicine Treatment for Attention-Deficit/Hyperactivity Disorder Across Australian Jurisdictions with Different School Enrolment Policies

Background: Children who are relatively young for their school grade are more likely to receive treatment for attention-deficit/hyperactivity disorder (ADHD). It is unclear whether the phenomenon also exists across Australia or is impacted by the school enrolment policy in place. Objective: We evaluated the association between children's relative age and initiation of ADHD medicines across Australian jurisdictions with different school enrolment policies and rates of delayed school entry. Methods: We used Australia-wide dispensing data for a 15% random sample of children 4-9 years of age in 2013-2017 to create a nationwide cohort. Due to high rates of delayed school entry in New South Wales (NSW), we used linked prescribing and education data for a cohort of NSW residents starting school in 2009 and 2012. We estimated incidence rate ratios (IRRs) for ADHD medicine across children's birth month, sex, and jurisdiction. We used asthma medicines as a negative control. Results: For girls, we observed a relative age effect in three out of five jurisdictions, with an IRR ranging from 1.3 to 2.8, comparing the youngest versus oldest birth month thirds. We observed more modest effects among boys, ranging from null to 1.5-fold. In NSW, the relatively youngest boys were less likely to initiate stimulant medicines than the oldest (IRR = 0.5, 95% confidence interval 0.29-0.78). We did not observe a relative age effect for initiation of asthma medicines. Conclusions: In jurisdictions with low rates of delayed entry, relatively young children were more likely to initiate ADHD medicines than their older classmates. We observed the inverse association in NSW where delayed entry was highest, likely reflecting the characteristics and needs of children who delay school entry for 1 year and become the oldest children in the grade. Increased awareness around children's maturity differences and school readiness may enhance appropriate diagnosis and treatment of ADHD.

Machine learning-based ABA treatment recommendation and personalization for autism spectrum disorder: an exploratory study

Autism spectrum is a brain development condition that impairs an individual's capacity to communicate socially and manifests through strict routines and obsessive-compulsive behavior. Applied behavior analysis (ABA) is the gold-standard treatment for autism spectrum disorder (ASD). However, as the number of ASD cases increases, there is a substantial shortage of licensed ABA practitioners, limiting the timely formulation, revision, and implementation of treatment plans and goals. Additionally, the subjectivity of the clinician and a lack of data-driven decision-making affect treatment quality. We address these obstacles by applying two machine learning algorithms to recommend and personalize ABA treatment goals for 29 study participants with ASD. The patient similarity and collaborative filtering methods predicted ABA treatment with an average accuracy of 81-84%, with a normalized discounted cumulative gain of 79-81% (NDCG) compared to clinician-prepared ABA treatment recommendations. Additionally, we assess the two models' treatment efficacy (TE) by measuring the percentage of recommended treatment goals mastered by the study participants. The proposed treatment recommendation and personalization strategy are generalizable to other intervention methods in addition to ABA and for other brain disorders. This study was registered as a clinical trial on November 5, 2020 with trial registration number CTRI/2020/11/028933.

Relative Age Effect in Attention Deficit/Hyperactivity Disorder at Various Stages of the Medicalization Process

Diagnosis and pharmacological treatment of ADHD are more common among the youngest children in a classroom, born in the months immediately preceding the school entry cutoff date. The mechanisms behind this phenomenon, called the relative age effect (RAE), are not yet well understood. Nearly all hypotheses involve the school system, various teachers’ actions, and concern children’s immaturity. However, most previous studies have been based on reports of health professionals’ diagnoses and prescriptions found in official databases rather than on reports of teachers’ behavior identification or suspicion of ADHD, despite their being at the first stages of the medicalization process. Our study overcomes this limitation by using reports of parents’ and teachers’ behavior identification or suspicion of ADHD within a three-level multilevel survey design, comprising 1294 children, 130 teachers, and 17 elementary public schools. The goal of our study was to investigate whether RAE stems (1) from adults’ judgement of the child’s expression of immaturity or (2) from the consequences associated with the child’s double burden of being immature and exhibiting ADHD behaviors. Our multilevel analyses put forward the first hypothesis only, supporting the medicalization of immaturity. RAE in ADHD seems mostly initiated by teachers’ pre-diagnostic actions toward younger children.

Age within schoolyear and attention-deficit hyperactivity disorder in Scotland and Wales

BACKGROUND

Previous studies suggest an association between age within schoolyear and attention-deficit hyperactivity disorder (ADHD). Scotland and Wales have different school entry cut-off dates (six months apart) and policies on holding back children. We aim to investigate the association between relative age and treated attention deficit hyperactivity disorder (ADHD) in two countries, accounting for held-back children.

METHODS

Routine education and health records of 1,063,256 primary and secondary schoolchildren in Scotland (2009-2013) and Wales (2009-2016) were linked. Logistic regression was used to examine the relationships between age within schoolyear and treated ADHD, adjusting for child, maternity and obstetric confounders.

RESULTS

Amongst children in their expected school year, 8,721 (0.87%) had treated ADHD (Scotland 0.84%; Wales 0.96%). In Wales, ADHD increased with decreasing age (youngest quartile, adjusted OR 1.32, 95% CI 1.19-1.46) but, in Scotland, it did not differ between the youngest and oldest quartiles. Including held-back children in analysis of their expected year, the overall prevalence of treated ADHD was 0.93%, and increased across age quartiles in both countries. More children were held back in Scotland (57,979; 7.66%) than Wales (2,401; 0.78%). Held-back children were more likely to have treated ADHD (Scotland OR 2.18, 95% CI 2.01-2.36; Wales OR 1.70, 95% CI 1.21-2.31) and 81.18% of held-back children would have been in the youngest quartile of their expected year.

CONCLUSIONS

Children younger within schoolyear are more likely to be treated for ADHD, suggesting immaturity may influence diagnosis. However, these children are more likely to be held back in countries that permit flexibility, attenuating the relative age effect.

Childhood Disorder: Dysregulated Self-Conscious Emotions? Psychopathological Correlates of Implicit and Explicit Shame and Guilt in Clinical and Non-clinical Children and Adolescents

This study examined psychopathological correlates of implicit and explicit shame and guilt in 30 clinical and 129 non-clinical youths aged 8-17 years. Shame and guilt were measured explicitly via two self-reports and a parent report, and implicitly by means of an Implicit Association Test (IAT), while a wide range of psychopathological symptoms were assessed with questionnaires completed by children, parents, and teachers. The results showed no differences of implicit and explicit shame and guilt between the clinical and non-clinical group, implying that dysregulation of these self-conscious emotions is not per definition associated with psychopathology. Correlational analyses indicated that self-reported explicit shame was positively associated with a broad range of internalizing psychopathology, while self-reported explicit guilt was associated with higher levels of anxiety and to some extent lower levels of externalizing psychopathology. Correlations with parent-rated shame and guilt revealed the same pattern of results but were in general weaker. Furthermore, implicit shame and guilt did not show significant correlations with the various measures of psychopathology. It can be concluded that the link between shame and guilt and psychopathology is complex, and partly dependent on the disorder under study and context-related factors defining the maladaptive nature of these self-conscious emotions.

Do You Really Want to Be Forever Young? Emotional Health and Psychosocial Well-being by Relative Birth Quarter in Canadian Adolescents

PURPOSE

Those born earlier within cohorts of similarly aged children tend to outperform peers in athletic and academic pursuits. Subsequent evidence suggests relatively younger children may also experience worse emotional and psychosocial health; however, evidence from middle adolescents is limited. This study assessed whether depression, anxiety, and psychosocial well-being differed by the relative birth quarter (RBQ) within a cohort of grades 9-12 in secondary schools across Canada.

METHODS

Data from the 2018-19 student self-report surveys of the cannabis use, obesity, mental health, physical activity, alcohol use, smoking, and sedentary behavior study were analyzed. Students having made normative progress were categorized into RBQs by the provincial enrollment cutoff date (n = 49,921). Hierarchical modeling approaches assessed whether self-reported depression, anxiety, psychosocial well-being, and positive controls differed by RBQ after controlling for covariates.

RESULTS

Despite relative age effects for positive control outcomes, no significant difference was detected for anxiety and depression scores or likelihood of meeting thresholds for having clinically relevant symptoms. However, a significant difference emerged between RBQs for psychosocial well-being scores; post hoc tests found that psychosocial well-being scores were lower in the fourth RBQ than those in all prior quarters.

DISCUSSION

Results agree with limited findings that relative age differences in emotional health are not significant in older cohorts. Nonetheless, relatively older individuals reported very small (d = .04-.05) advantages in psychosocial well-being than their youngest peers, which aligns with previous data. Longitudinal approaches to assess relative age effects on mental health during and throughout the transition into middle adolescence are warranted.

The Combined Effects of Young Relative Age and Attention-Deficit/Hyperactivity Disorder on Negative Long-term Outcomes

OBJECTIVE

Young relative age (ie, being among the youngest in a school class) and attention-deficit/hyperactivity disorder (ADHD) are both potential risk factors for adverse long-term outcomes. Young relative age also increases the risk of ADHD diagnosis. Using data from Swedish national registers, we investigate the independent and joint long-term effects of young relative age and ADHD on educational achievement, substance use disorder (SUD), criminality, and depression.

METHOD

We identified a national cohort of individuals with young relative age (born November-December) and a comparison group with old relative age (born January-February). Of the total sample of 297,840 individuals, 6,528 individuals had a diagnosis of ADHD in childhood. The 4 outcomes were measured at ages 15 to 23 years. We examined main, additive, and interactive effects of young relative age and ADHD on long-term outcomes.

RESULTS

In the individuals without ADHD, young relative age was associated with increased risk of depression (odds ratio [OR] = 1.14 [95% CI =1.09-1.20]), SUD (OR = 1.14 [1.09-1.20]), and low educational achievement (OR = 1.17 [1.14-1.20]), but not criminality (OR = 1.00 [0.98-1.03]). In the individuals with ADHD, young relative age was associated with increased risk of SUD (OR = 1.23 [1.01-1.50]) and low educational achievement (OR = 1.12 [1.00-0.26]; CI included 1), but not depression or criminality (OR = 0.88 [0.73-1.07] and OR = 0.89 [0.79-1.01], respectively). An interaction emerged between young relative age and ADHD for depression (OR = 0.78 [0.64-0.95]).

CONCLUSION

We observed relative age effects that add to the evidence supporting a more flexible approach to school starting age and that emphasize the importance of careful age-match comparisons during assessment of childhood ADHD symptoms.

National Norms for the Vanderbilt ADHD Diagnostic Parent Rating Scale in Children

OBJECTIVE

To provide national norms and percentiles for both research and clinical scoring modalities of the Vanderbilt Attention Deficit/Hyperactivity Disorder (ADHD) Diagnostic Parent Rating Scale (VADPRS) for a representative sample of children ages 5-12 in the United States.

METHOD

The five clinical subscales of the VADPRS were completed by 1,570 caregivers of children ages 5-12 in the United States, with children representative of the national population on key demographic variables including race, sex, ethnicity, family income, and family educational level. Descriptive statistics and measures of internal consistency of both dimensional and symptom count scoring were provided for each of the five clinical subscales of the inventory, as well as percentiles and group comparisons for select dimensional scoring subscales based on age and child sex.

RESULTS

Measures of internal consistency for each subscale using both scoring modalities of the VADPRS ranged from high to acceptable. There were statistically significant differences among the different subscales for both age (ADHD hyperactivity, anxiety/depression) and sex [both presentations of ADHD, oppositional defiant disorder (ODD)] for the total sample. These differences, however, were modest in magnitude and unlikely to be clinically meaningful.

CONCLUSIONS

This study enhances the research and clinical utility of the VADPRS by providing national norms and percentiles for each of its subscales. Differences between age and sex across the sample were statistically significant for two of the subscales (Hyperactivity and Anxiety/Depression) with additional subscales significant for sex alone (Inattentive and ODD), but these differences were not substantial enough to indicate a need for separate cut-offs for screening purposes.

Age at school entry and reported symptoms of attention-deficit/hyperactivity in first graders: results of the prospective cohort study ikidS

Young age at school entry (ASE) is related to attention-deficit/hyperactivity disorder in higher grades. The reason for this association is unclear, but medical oversupply and stress-related factors are discussed. We aimed to investigate whether ASE is associated with reported symptoms of attention-deficit/hyperactivity (ADH) already in first grade. Data of a population-based prospective cohort study (N = 2003; Mainz-Bingen region; Rhineland-Palatinate; Germany) with baseline assessments prior to school entry and two follow-ups during first grade were analysed. ADH symptoms were assessed by parent and teacher versions of the Strengths and Difficulties Questionnaire. Associations between ASE and scores of the hyperactivity/inattention subscale (range 0-10) were investigated by regression analysis and adjusted for potential confounders and baseline symptoms prior to school entry. In total, 1633 children (52% boys, mean ASE 6.5 years) were included. There were no relationships between ASE and parent-reported scores of the hyperactivity/inattention subscale prior to school entry and 3 months thereafter. However, at the end of first grade, ASE was negatively associated with the hyperactivity/inattention subscale in parent (- 0.7 subscale points per year ASE, standard error = 0.16, p < 0.0001) and teacher reports (- 1.2 subscale points per year ASE, standard error = 0.25, p < 0.0001). This ASE effect appeared more pronounced in girls than in boys. Young ASE is related to more reported symptoms of ADH at the end of first grade, but not before. The evolvement of this effect during first grade may be a clue to ASE-related stress factors.

ADHD diagnosis and methylphenidate consumption in children and adolescents: A systematic analysis of health databases in France over the period 2010-2019

CONTEXT

ADHD is the most common mental disorder in school-aged children. In France, methylphenidate is the only drug authorized for ADHD. Here, we describe the pattern of ADHD diagnosis and methylphenidate prescription to children and adolescents from 2010 to 2019.

METHODS

We conducted a retrospective cohort study of all beneficiaries of the French general health insurance scheme (87% of the population, 58 million people). We extracted information for all children and adolescents aged 0-17 years who received: (1) A diagnosis of ADHD (34,153 patients). (2) At least one methylphenidate prescription (144,509 patients). We analyzed the clinical, demographic, institutional, and social parameters associated with ADHD diagnosis and methylphenidate consumption in France.

RESULTS

The ADHD diagnosis among children and adolescents increased by 96% between 2010 and 2019. ADHD diagnosis affects more boys than girls. About 50.6% of children hospitalized with a diagnosis of ADHD in 2017 also had another psychiatric diagnosis. The rate of children hospitalized with an ADHD diagnosis and treated with MPH varied between 56.4 and 60.1%. The median duration of MPH treatment for a 6-year-old ADHD child initiated in 2011 is 7.1 years. In 2018, 62% of ADHD children were receiving at least one psychotropic medication. Between 2010 and 2019, methylphenidate prescription increased by +56% for incidence and +116% for prevalence. The prevalence of methylphenidate prescription reached between 0.61 and 0.75% in 2019. Boys are predominantly medicated. The median duration of treatment among 6-year-olds in 2011 was 5.5 years. The youngest children received the longest treatment duration. Diagnoses associated with methylphenidate prescription did not always correspond to the marketing authorization. Among children receiving the first prescription of methylphenidate, 22.8% also received one or more other psychotropic drugs during the same year. A quarter of initiations and half of renewals were made outside governmental recommendations. Educational and psychotherapeutic follow-up decreased from 4.1% in 2010 to 0.8% in 2019. French children and adolescents, who were the youngest in their class were more likely to be diagnosed (55%) and prescribed methylphenidate (54%). Children from disadvantaged families had an increased risk of ADHD diagnosis (41.4% in 2019) and methylphenidate medication (25.7% in 2019).

Evaluating the Neuroimaging-Genetic Prediction of Symptom Changes in Individuals with ADHD

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder that could persist into adulthood with known abnormalities in brain structure. Genetics also play an important role in the etiology of the disorder and could affect the disorder trajectory. In this study, we investigated the prediction power of brain image and genomic features for symptom change in 77 individuals with ADHD as part of NeuroIMAGE cohort. Gray matter components and working memory assessments at baseline, as well as gene scores of interest, were used to predict the changes in the two symptom domains: inattentive and hyperactive/impulsive, an average of 4 years. A linear regression model coupled with various feature selection approaches, including leave-one-out-cross-validation (LOOCV), stability selection with resampling, and permutation tests, was implemented to mitigate the overtraining potential caused by small sample sizes. Results showed that traditional LOOCV overestimated the prediction power. We proposed a novel stability selection with the threshold set by permutation tests, which provided more objective assessment. Using our proposed procedure, we identified a statistical promising prediction model for inattention symptom change; the consistent correlation between predicted values and measured values during model training, validating and hold out testing (r=0.64, 0.53, 0.46, respectively), but the p value is not significant in the holdout test. The selected features include age, gray matter in the insula, genes OSBPL1A, CTNNB1, PRPSAP2, ACADM, and polygenic risk score of education attainment, which have been previously reported to be associated with ADHD. We speculate that significant associations may be observed with a large sample size.

Relative age and specific learning disorder diagnoses: A Finnish population-based cohort study

Background

Being among the youngest in class has previously been associated with attention-deficit/hyperactivity disorder (ADHD) and academic disadvantage, but the relative age effect on learning disorders is less well understood. This study examined whether relatively young children are more likely to be diagnosed with specific learning disorders than their older peers.

Methods

The setting included all 388,650 children born singleton in Finland from 1996 to 2002. Cases diagnosed with specific learning disorders in specialized health care by the age of 10 were identified from national registers. Cumulative incidences of specific learning disorders and the corresponding incidence rate ratios (IRRs) and 95% confidence intervals (CIs) were calculated for each birth month compared to January.

Results

During follow-up, 3162 (0.8% of 388,650) children were diagnosed with a specific learning disorder. Children born in December displayed higher cumulative incidences for specific learning disorders than children born in January (IRR: 1.77, 95% CI: 1.50-2.11). The findings were similar for girls (IRR: 2.01, 1.44-2.83) and boys (IRR: 1.70, 1.39-2.08). ADHD did not explain the association, as the IRR for the youngest children with specific learning disorders and ADHD was 1.59 (1.13-2.26) compared to those without ADHD (IRR: 1.84, 1.51-2.24).

Conclusions

Relatively younger children in Finnish schools were more likely to be diagnosed with a specific learning disorder by the age of 10. Increased awareness of how relative age differences affect the likelihood for children to be diagnosed with specific learning disorders is needed among parents, clinicians, and teachers.

Overdiagnosis of Attention-Deficit/Hyperactivity Disorder in Children and Adolescents: A Systematic Scoping Review

IMPORTANCE

Reported increases in attention-deficit/hyperactivity disorder (ADHD) diagnoses are accompanied by growing debate about the underlying factors. Although overdiagnosis is often suggested, no comprehensive evaluation of evidence for or against overdiagnosis has ever been undertaken and is urgently needed to enable evidence-based, patient-centered diagnosis and treatment of ADHD in contemporary health services.

OBJECTIVE

To systematically identify, appraise, and synthesize the evidence on overdiagnosis of ADHD in children and adolescents using a published 5-question framework for detecting overdiagnosis in noncancer conditions.

EVIDENCE REVIEW

This systematic scoping review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) Extension for Scoping Reviews and Joanna Briggs Methodology, including the PRISMA-ScR Checklist. MEDLINE, Embase, PsychINFO, and the Cochrane Library databases were searched for studies published in English between January 1, 1979, and August 21, 2020. Studies of children and adolescents (aged ≤18 years) with ADHD that focused on overdiagnosis plus studies that could be mapped to 1 or more framework question were included. Two researchers independently reviewed all abstracts and full-text articles, and all included studies were assessed for quality.

FINDINGS

Of the 12 267 potentially relevant studies retrieved, 334 (2.7%) were included. Of the 334 studies, 61 (18.3%) were secondary and 273 (81.7%) were primary research articles. Substantial evidence of a reservoir of ADHD was found in 104 studies, providing a potential for diagnoses to increase (question 1). Evidence that actual ADHD diagnosis had increased was found in 45 studies (question 2). Twenty-five studies showed that these additional cases may be on the milder end of the ADHD spectrum (question 3), and 83 studies showed that pharmacological treatment of ADHD was increasing (question 4). A total of 151 studies reported on outcomes of diagnosis and pharmacological treatment (question 5). However, only 5 studies evaluated the critical issue of benefits and harms among the additional, milder cases. These studies supported a hypothesis of diminishing returns in which the harms may outweigh the benefits for youths with milder symptoms.

CONCLUSIONS AND RELEVANCE

This review found evidence of ADHD overdiagnosis and overtreatment in children and adolescents. Evidence gaps remain and future research is needed, in particular research on the long-term benefits and harms of diagnosing and treating ADHD in youths with milder symptoms; therefore, practitioners should be mindful of these knowledge gaps, especially when identifying these individuals and to ensure safe and equitable practice and policy.

Relative age is associated with bullying victimisation and perpetration among children aged eight to nine

AIM

To assess whether relative age was associated with bullying involvement and whether the associations were independent of child psychiatric symptoms.

METHODS

Bullying was assessed among 8576 children in the second grade, aged 8 years, by using four cross-sectional population-based studies with identical methodology completed by children, parents and teachers in 1989 (response rate 97%), 1999 (93%), 2005 (90%) and 2013 (86%). The main outcomes were bullying victimisation and perpetration. Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated with the relatively oldest as the reference group and adjusted for child psychiatric symptoms.

RESULTS

The relatively youngest children, born September to December, were compared with the relatively oldest, born January to April. The youngest children had increased odds of being victims according to child (OR 1.2, 95% CI 1.1-1.4) and parent reports (OR 1.2 95% CI 1.008-1.4). The youngest also had decreased odds of being perpetrators according to child (OR 0.8, 95% CI 0.7-0.96) and teacher reports (OR 0.8, 95% CI 0.7-0.95). These findings were independent of psychiatric symptoms.

CONCLUSION

The relative age effects which were found in bullying involvement were independent of psychiatric symptoms. Considering this newly recognised risk factor for victimisation is important within anti-bullying practices.

Children's Relative Age and ADHD Medication Use: A Finnish Population-Based Study

OBJECTIVES

The youngest children in a classroom are at increased risk of being medicated for attention-deficit/hyperactivity disorder (ADHD). We examined the association between children's birth month and ADHD medication rates in Finland.

METHODS

Using a population-based study, we analyzed ADHD medication use among children born in 2005 to 2007. Cases (n = 7054) were identified from the first purchase of medication for ADHD. Cox proportional hazard models and hazard ratios (HRs) were examined by birth month and sex. Finnish children start first grade in the year of their seventh birthday. The cutoff date is December 31.

RESULTS

Risk of ADHD medication use increased throughout the year by birth month (ie, January through April to May through August to September through December). Among boys born in September to December, the association remained stable across cohorts (HR: 1.3; 95% confidence interval [CI]: 1.1-1.5). Among girls born in September to December, the HR in the 2005 cohort was 1.4 (95% CI: 1.1-1.8), whereas in the 2007 cohort it was 1.7 (95% CI: 1.3-2.2). In a restricted follow-up, which ended at the end of the year of the children's eighth birthday, the HRs for boys and girls born in September to December 2007 were 1.5 (95% CI: 1.3-1.7) and 2.0 (95% CI: 1.5-2.8), respectively.

CONCLUSIONS

Relative immaturity increases the likelihood of ADHD medication use in Finland. The association was more pronounced during the first school years. Increased awareness of this association is needed among clinicians and teachers.

Gender- and age-stratified analyses of ADHD medication use in children and adolescents in Finland using population-based longitudinal data, 2008-2018

Aims: This study examined medication use for attention-deficit/hyperactivity disorder (ADHD) among children and adolescents by gender in Finland during 2008-2018. Methods: Aggregated data on medication use for ADHD from 2008 to 2018 were extracted from the nationwide register on reimbursed prescriptions. The annual prevalence of ADHD medication use was calculated as the number of children (6-12 years) and adolescents (13-17 years) per calendar year with at least one ADHD medication purchase divided by the number of children and adolescents in the population. Population prevalence for children was also examined by birth month. Results: In 2008, the prevalence rates for males were 1.26% in children and 0.93% in adolescents, and for females 0.21% and 0.14%, respectively. In 2018, the prevalence rates for males were 4.42% in children and 4.21% in adolescents, and for females 0.99% and 1.28%, respectively. Male-to-female ratios decreased during the study period from 6.0:1 to 4.5:1 (children) and from 6.6:1 to 3.3:1 (adolescents). ADHD medication use was more common among males and females (aged 6-12 years) born in May-August or September-December than among males and females born in January-April. Conclusions: The prevalence of ADHD medication use has continued to increase in Finland. Although use has increased more rapidly among females resulting in lower male-to-female ratios, medication use among females is considerably lower compared with males. Consequently, gender discrepancy in 2018 was relatively large, particularly among children. Future studies should also consider reporting annual prevalence by children's birth month.