Children are being wrongly diagnosed with mild or moderate levels of attention-deficit-hyperactivity disorder (ADHD) because medical rules have been softened, according to major international research.
The numbers of children diagnosed with ADHD globally have “risen steeply over the last decade”, according to the joint Australian-Dutch research.
However, they warn that the numbers being diagnosed could jump even more significantly following changes to international medical diagnostic rules introduced earlier this year.
The paper, published today by the British Medical Journal, is written by Rae Thomas from Bond University, Australia; Prof Geoffrey Mitchell from the University of Queensland and Laura Batstra, assistant professor at the University of Groningen in the Netherlands.
“Severe cases of ADHD are obvious, but in mild and moderate cases – which constitute the bulk of all ADHD diagnoses – subjective opinions of clinicians differ,” they write.
Urging “conservative diagnosis”, the team recommended guidelines operating in Britain, which advocate “a watchful waiting period of 10 weeks”, followed by a parent training programme and then referral onwards if symptoms do not improve.
Calling for changes, they said that reductions in the “threshold for diagnosing ADHD devalues the diagnosis in those with serious problems”.
Children are diagnosed according to criteria laid down in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), or in the International Classifications of Diseases (ICD-10).
The rules laid down by ICD-10 are “more restrictive”, say the researchers, but “most practitioners use DSM” – but the latter has been broadened even further in its scope.
Despite extensive research, medical science is “no closer to understanding the cause or causes” of ADHD.
“The broadening of the diagnostic criteria in DSM-5 is likely to increase what is already a significant concern about overdiagnosis.
“It risks resulting in a diagnosis of ADHD being regarded with scepticism to the harm of those with severe problems who unquestionably need sensitive, skilled specialist help and support,” the three declared.
The latest changes to the DSM-5 guidelines widen “the definition of ADHD by expanding behavioural descriptions to include more examples and increasing the maximum age of symptom onset from seven to 12 years.
“These changes are a cause for concern because they increase the risk of confusing ADHD with normal development processes, such as pubertal restlessness and distractibility.”
Furthermore, the researchers warn that the DSM-5 wording to be used to describe impaired functioning has changed from "clinically significant" to something that interferes "with or reduce the quality of social, academic, or occupational functioning."
Prevalence of ADHD
The reported prevalence of ADHD in the United States rose by nearly 50 per cent between 1997 and 2007: "It is likely that clinicians are better at detecting and diagnosing ADHD – but it is also thought that some of the rise reflects overdiagnosis or misdiagnosis."
In the United States, 86 per cent of children said to have ADHD are described as being mildly, or moderately affected by the disorder, which causes hyperactivity, impulsivity and intention.
In Australia, the amount of drugs prescribed to treat children rose by 72 per cent between 2001 and 2001, while in Britain prescriptions doubled for children and adolescents and jumped four-fold for adults between 2003 and 2008.
Research so far offers “differing conclusions” about the benefits of drug treatments “in the short term, and few studies have examined long-term benefits”.