We assume that diagnosis is good. If there’s something wrong, surely it’s best to know that there’s something wrong. Then you can do something about it.
So if you have ADHD, surely it’s best to get a diagnosis?
Apparently not.
In 2022 Australian Luise Kazda and her colleagues published research that found teenagers who were diagnosed with ADHD fared worse than teenagers exhibiting the same behaviours, but not diagnosed with ADHD.
The Longitudinal Study of Australian Children identified 393 adolescents who had been diagnosed with ADHD in earlier years, and matched them with 393 similar adolescents who had shown the same ADHD behaviours but had not been given a formal diagnosis of ADHD at the time. The adolescents who had been given a formal diagnosis felt less accepted and included at school, said they did worse academically, displayed more negative social behaviours, and were more likely to harm themselves. On no measure did the diagnosed teenagers rate themselves as better than the undiagnosed teenagers.
Kazda’s finding was the opposite of her expectation that Australian teenagers would benefit from a diagnosis of ADHD and the consequent treatment. In fact although the teenagers’ behaviours had been the same, those diagnosed with ADHD did worse.
This study would be intriguing, even if it were the only one signalling that worse outcomes from ADHD diagnoses were possible. But there are others: an Irish study by Cliodhna O’Connor and Fiona McNicholas found the same effect.
When O’Connor and McNicholas analysed data from Growing Up in Ireland – the National Longitudinal Study of Children, they found that by age 13, those who had been given an ADHD diagnosis at 9 years old were doing worse than those who had the same behaviours at 9, but who had not been given a diagnosis. Diagnosed children showed more emotional and peer relationship problems, displayed less prosocial behaviour, and reported poorer self concept. For example, they believed they caused trouble and couldn’t comply with adult expectations.
We need to pay attention.
Here we have similar results from two independent longitudinal studies, examining different people in different places. In both studies, ADHD diagnoses resulted in worse outcomes for the children the diagnoses were supposed to help. In contrast, no longitudinal study shows that children do better with ADHD diagnoses than without.
Can we trust these studies?
As has been documented extensively, such as here and here, ADHD research is at high risk of bias. So we need to look carefully at the quality of the studies and possible sources of bias.
Firstly, these studies did not receive industry funding, which we know affects the design, outcomes and recommendations of mental health research. The lack of industry funding makes the findings likely to be reliable.
Secondly, Kazda’s team predicted:
that children and adolescents [would] benefit from an ADHD diagnosis and that this may result in better Quality of Life.
They expected that the diagnosed children would do better - but found the opposite. And still, they published the surprising outcome.
Publishing this unexpected result is important in itself because of psychology’s "publication bias". Research findings that are predicted or show a substantial difference are more likely to be published than studies with unexpected or non-significant results. Unexpected and non-significant outcomes are often ‘filed away’ without publication. This creates a systemic bias in published research. When writers summarise what we know, they can only ‘see’ what is published. They can’t ‘see’ the studies sitting in researchers’ filing cabinets. And so summaries don’t include all studies that have been done, leading to false conclusions. Kazda’s publication of a study with unexpected outcomes strengthens the assurance we can have in its findings.
Thirdly, one author of the Irish study, Fiona McNicholas, has received industry funding and has published research in line with common ADHD views. She has been a member of a Shire Pharmaceuticals advisory board and has received funding from Ortho-McNeil-Janssen Pharmaceuticals, although not specifically for this study. Despite these industry connections, McNicholas still published a result that didn’t match the expectations of the ADHD orthodoxy. In this case, sharing results that don’t fit the normal narrative, increases the confidence we can have in this study.
So we should take the results of these studies seriously because unlike most ADHD research, in these studies there is little risk of bias.
Why might diagnosis be harmful?
Although both Kazda’s and O’Connor’s studies indicate there are risks for children diagnosed with ADHD, they can’t explain how diagnosis has this effect. Why would diagnosis make children’s lives worse rather than better? These studies don’t answer this question directly. But some possibilities are:
Firstly, the diagnosed group of children might be different from the not-diagnosed children in some way that isn’t yet obvious. This is unlikely because both studies looked extensively but didn’t find differences between the groups at the point of diagnosis - aside from their ADHD diagnosis status. Instead, the studies found that children became different between diagnosis and being re-evaluated as teenagers.
Another possibility is that labelling children’s attention and activity levels as “disorders” - that is, giving children ADHD diagnoses - leads those children to develop negative views of themselves or to understand themselves as broken. We already know that biological explanations of mental illness are associated with increased stigma or negative attitudes towards mental illness and can dissuade people from seeking help in order to avoid labels and stigma. In contrast, teenagers who drop self-labels have been found to have improved self esteem. So, diagnosis may lead to worse outcomes because of the meaning a person makes of being diagnosed, labelled or marked ‘different’ from peers.
Lastly, ADHD diagnoses might change how parents, teachers and others think about and treat children, contributing to poorer outcomes in diagnosed children. It’s possible that children internalise negative responses or lowered expectations from others as a result of diagnosis, contributing to a cycle of lowered self-worth and achievement.
Where does this leave us?
In the long term, children are better off without an ADHD diagnosis - even if they show all the behaviours that could lead to a diagnosis. The two longitudinal studies are reliable, but don’t explain why diagnosis makes things worse for diagnosed teenagers.
How does this information help us? Based on these findings:
Parents, teachers and clinicians need to know that there are risks from ADHD diagnoses.
Clinicians should be cautious about diagnosing ADHD in children, especially when behaviours are mild. Any harms associated with an ADHD diagnosis need to be carefully weighed with the potential benefits.
Parents and clinicians can address concerns about children’s behaviours without seeking diagnoses, by supporting parents to help their children and by supporting children to understand themselves and what helps them thrive.
Clinicians, teachers and schools can support children who exhibit ADHD behaviours to thrive in school.
It seems preferable to speak in terms of variation and difference than in terms of deviation and disorder (Batstra & Timimi).
Laura Batstra and Sami Timimi’s wise words are a good place to close. Perhaps many mental “disorders”, including ADHD, would be better thought of as variation and difference between people. Labelling variation as deficit and disorder can make things worse. Maybe we can support people better by talking them through the effects of this variation on themselves and others, and helping them and their communities decide whether and how they want to do accommodate or change it.
Kazda L, McGeechan K, Bell K, et al. (2022). Association of Attention-Deficit/Hyperactivity Disorder Diagnosis With Adolescent Quality of Life. JAMA network open, 5(10), e2236364. https://doi.org/10.1001/jamanetworkopen.2022.36364
O'Connor C, & McNicholas F. (2020). What Differentiates Children with ADHD Symptoms Who Do and Do Not Receive a Formal Diagnosis? Results from a Prospective Longitudinal Cohort Study. Child psychiatry and human development, 51(1), 138–150. https://doi.org/10.1007/s10578-019-00917-1