Overview: Research reports that the youngest children in a class are more likely to be diagnosed with ADHD, suggesting that immaturity in an age group may influence the diagnosis.
Source: University of Nottingham
New research with experts from the University of Nottingham shows that children who are younger than their classmates are more likely to receive treatment for Attention Deficit Hyperactivity Disorder (ADHD) within a school year, suggesting immaturity may influence diagnosis.
The study, published in BMC Public Healthlooked at the link between age and ADHD, with experts linking health and education data from more than 1 million children in Scotland and Wales.
The study was led by experts from Swansea University and the University of Glasgow, along with colleagues from the University of Nottingham.
There are indications that worldwide the prevalence of ADHD among school-age children is around three to five percent, fairly uniform. Internationally, however, there are large differences in the rates of clinical diagnosis and treatment.
Previous studies have found a link between age within the school year and ADHD, especially in countries where more children are diagnosed with ADHD. This latest study aimed to see if this is also the case in the UK, where prescribing rates are relatively low.
Another important aim was to examine whether allowing more flexibility around school start dates could reduce the impact of this so-called “relative age effect” – whereby adults could compare the youngest children to their oldest peers in the same age group. age group and immaturity could be misattributed to more serious difficulties.
Scotland and Wales have different school entry closing dates (which are six months apart) and policies to delay children by an academic year. Comparing the two countries, therefore, allows for a useful natural experiment to examine the relationship between age within the school year and ADHD, and whether it is influenced by child restraint policies.
The team of experts matched the education and health records of 1,063,256 primary and secondary school students in Scotland (between 2009 and 2013) and Wales (between 2009 and 2016), to examine the relationships between age within the school year and ADHD treated (i.e., reception of medication for ADHD).
Overall, 0.87% of the children in the study were treated for ADHD. The team found that in Wales, children who were the youngest in their class were more likely to be prescribed medication for ADHD.
In Scotland, however, this effect was masked as there was found to be more flexibility, causing younger children with attention or behavioral problems to be held up for a year earlier in the school year.
Kapil Sayal, professor of child and adolescent psychiatry at the University of Nottingham’s School of Medicine and the Center for ADHD and Neurodevelopmental Disorders Across the Lifespan at the Institute of Mental Health, is a joint senior author of the study.
He said: “The findings of this study have a range of implications for teachers, parents and clinicians. With an age difference of up to 12 months in the same class, teachers and parents can misattribute a child’s immaturity. This can lead to younger children being in the classroom are more likely to be diagnosed with and given medication for ADHD.
“Regardless of your school enrollment date, your month of birth should have no bearing on whether you receive a diagnosis or prescribe medication for ADHD.
“Parents and teachers, as well as clinicians conducting ADHD assessments, should consider the age of the child within the school year. From an educational perspective there should be flexibility with an individualized approach to [what] best suited to the child’s educational and behavioral needs.
“Our research has shown that when there is more flexibility, the youngest are no longer more likely to be treated for ADHD within the school year.”
About this ADHD research news
Original research: Open access.
†Age Within School and Attention Deficit Hyperactivity Disorder in Scotland and Walesby Michael Fleming et al. BMC Public Health
Age Within School and Attention Deficit Hyperactivity Disorder in Scotland and Wales
Previous studies suggest a link between age within the school year and attention deficit hyperactivity disorder (ADHD). Scotland and Wales have different school entry closing dates (six months apart) and child restraint policies. We wish to investigate the association between relative age and treated attention deficit hyperactivity disorder (ADHD) in two countries, taking withheld children into account.
Routine education and health records of 1,063,256 primary and secondary school students in Scotland (2009-2013) and Wales (2009-2016) were linked. Logistic regression was used to examine the relationships between age within the school year and ADHD treated, adjusted for confounders of child, motherhood, and obstetrics.
Of the children in the expected school year, 8,721 (0.87%) had ADHD treated (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 quartile. If the children withheld in the analysis of their expected year were included, the overall prevalence of treated ADHD was 0.93%, increasing across the age quartiles in both countries. More children were detained in Scotland (57,979; 7.66%) than in Wales (2,401; 0.78%). Children who were withheld were more likely to have had ADHD treated (Scotland OR 2.18, 95% CI 2.01-2.36; Wales OR 1.70, 95% CI 1.21-2.31) and 81, 18% of withheld children would be in the youngest quartile of their expected year.
Children younger within the school year are more likely to be treated for ADHD, suggesting immaturity may influence the diagnosis. However, these children are more likely to be held back in countries that allow flexibility, thus attenuating the relative age effect.