Updated 02 October 2019

Youngest in classroom diagnosed more often with ADHD and other problems

Children in the same [school] year as each other can be nearly a whole year apart in terms of age and the younger ones are more likely to be diagnosed with hyperactivity disorders.

If a child can't sit still or blurts out random thoughts in kindergarten or first grade, does the child have attention-deficit/hyperactivity disorder (ADHD)? Or is the youngster just not yet mature enough to sit still?

Both are possibilities, and whichever might be true, new research suggests that the youngest kids in class are being diagnosed with ADHD, intellectual disability and even depression around 30% more often than their oldest classmates.

Just an association

"Children in the same [school] year as each other can be nearly a whole year apart in terms of age. We have known for some time that children who are young in their year at school tend to do less well academically, and are more likely to be diagnosed with hyperactivity disorders," said study co-author Jeremy Brown, from the London School of Hygiene and Tropical Medicine, in England.

Brown noted that this study wasn't designed to determine the cause for these issues, just to find an association. But he said there are a number of potential reasons for the link.

"Younger children may find it harder to concentrate in class, leading to increased diagnoses of hyperactivity. Inferior academic performance and poorer peer relationships could have negative consequences on mental health," he explained.

For the study, the researchers reviewed electronic health care records from more than one million school children in the United Kingdom.

The investigators found that children born in the last quarter of a school year were 36% more likely than kids born in the first quarter of a school year to be diagnosed with ADHD. The youngest kids were 30% more likely to have an intellectual disability and 31% more likely to have depression than their older classmates.

Children born in the second quarter appeared to have a slight disadvantage compared to the older kids in terms of intellectual disability. And, kids born in the third quarter of the year were 20% more likely than the oldest kids to have an intellectual disability, the findings showed.

Solution not clear

Brown said about 800 000 kids start primary school in the United Kingdom each year. "Based on our findings, over the course of their schooling up to age 16 years, we would expect around 500 more of the youngest quarter in the year might be diagnosed with depression, compared to the oldest," he said.

For ADHD, that number was 1 200 more of the youngest children, and for intellectual disability, the difference would be about 500 more of the youngest children with a problem, he added.

Brown said the solution isn't clear, and more research is needed. More support for younger children might be of value, he suggested. It also might help to have a fairer and clearer process for delaying school entry to young and developmentally immature children.

Dr Meg Benningfield, director of the division of child and adolescent psychiatry at Vanderbilt University in Nashville, Tennesee, said, "If you compare a four-year-old to a five-year-old, there's a big difference developmentally. When younger children are held to the same standard as older kids, there's a risk for both overdiagnosis and underdiagnosis." (Just as an over-fidgety kid might be assumed to have ADHD when they don't, the reverse is also true, and teachers might excuse poor behaviour in a child because they're young, when they actually have ADHD.)

Benningfield said that if parents are concerned about their child's behaviour – no matter their age – they should talk with their child's paediatrician or a child and adolescent psychiatrist, if available.

She recommended helping children who are younger than their class peers focus on how they, themselves, are improving. What can you do today that you couldn't do yesterday? How did you do on your spelling test today compared to last week? Teach them to look at how they're growing and getting better, and minimise comparisons to other children.

Surprised by findings

Dr Andrew Adesman is chief of developmental and behavioural paediatrics at Cohen Children's Medical Center in New Hyde Park, New York.

He said that previous studies have shown the connection to ADHD and younger age in a grade. But he was surprised by the findings on intellectual disability. Adesman said that IQ test scoring is adjusted based on a child's exact age, so he wouldn't have expected that difference.

The "findings suggest that more consideration should be given to a child's age relative to his or her classmates when concerns about short attention span, impulsivity or restlessness are first raised."

Adesman also said that a child's birthdate shouldn't be the sole factor in deciding when kids start school. He said that a child's maturity level should also be considered.

The study was published online in JAMA Pediatrics.

Image credit: iStock


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ADHD Expert

Dr Renata Schoeman has been in full-time private practice as a general psychiatrist (child, adolescent and adult psychiatry) since 2008, currently based in Oude Westhof (Bellville). Renata also holds appointments as senior lecturer in Leadership (USB) and as a virtual faculty member of USB Executive Development’s Neuroleadership programme. She serves on the advisory boards of various pharmaceutical companies, as a director of the Psychiatric Management Group (PsychMG) and is the co-convenor of the South African Society of Psychiatrist (SASOP) special interest group for adult ADHD, and co-founder of the Goldilocks and The Bear Foundation ( She is passionate about corporate mental health awareness and uses her neuroscience background to assist leaders in equipping them to become balanced, healthy and dynamic leaders that take their own and their team’s emotional, intellectual, social health and physical needs into account. Renata is academically active and enjoys research and collaborative work, has published in many peer-reviewed journals, and has presented at local and international congresses. She is regularly invited to present at conferences and to engage with the media. During her post-graduate studies, she trained at Harvard, Boston in neurocognition and neuroimaging. Her awards include, amongst others, the Young Minds in Psychiatry award from the American Psychiatric Association, the Discovery Foundation Fellowship award, a Thuthuka award from the NRF, and a MRC Fellowship. She also received the Top MBA student award and the Director’s award from USB for 2015. She was a finalist for the Businesswomen’s Association of South Africa’s Businesswoman of the Year Award for 2016, and received the Excellence in Media Work award from SASOP during 2016.

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