Experts argue that ADHD is 'overdiagnosed'
An article published by the British Medical Journal, claiming that attention-deficit hyperactivity disorder (ADHD) is being overdiagnosed, has been reported in some of the papers
The Daily Mail warned that some children diagnosed with ADHD were being given “needless and possibly harmful” treatment. The Independent talked about “Hyperactive UK” as prescriptions for drugs used in ADHD, such as Ritalin, have “soared” 50% in five years.
It is important to stress that these headlines are not prompted by new research or updated guidelines. The article is in fact an opinion piece by three health professionals.
The writers argue that the definition of ADHD in doctors’ guidelines has broadened in recent years. And this has contributed to a steep rise in diagnosis of and drug prescriptions for the disorder, particularly among children. This may mean “unnecessary and possibly harmful medical treatment” for some individuals. In the UK, estimated drug costs for the disorder are now £200m.
The authors call for a more cautious diagnostic approach to help reduce the risk of overdiagnosis.
What is ADHD?
Attention deficit hyperactivity disorder (ADHD) is a group of behavioural symptoms that include inattentiveness, hyperactivity and impulsiveness. Common symptoms of ADHD include:
- a short attention span
- restlessness or constant fidgeting
- being easily distracted
ADHD can occur in people of any intellectual ability. However, many people with ADHD also have learning difficulties. They may also have additional problems such as sleep disorders.
Symptoms of ADHD are often noticed at an early age, and may become more noticeable when a child’s circumstances change, such as when they start school.
A person with ADHD usually has symptoms characteristic of one of the three subtypes of the condition. The subtypes are:
- ADHD mainly inattentive – problems with attention span and concentration
- ADHD mainly hyperactive-impulsive – problems with behaviour and impulse control
- ADHD combined – problems with all of the above
ADHD combined is the most common subtype of ADHD.
There is increasing evidence that ADHD is not just a childhood disease and many adults may also be affected by it.
How is ADHD diagnosed?
There are several criteria which must be met for a child to be diagnosed with ADHD. The criteria are outlined in the “psychiatrists bible” , the Diagnostic and Statistical manual of Mental Disorders (DSM-5). (For more information on the DSM-5 see Behind the Headlines’ special report on the ‘psych bible’).
To be diagnosed with ADHD a child or adult must meet the diagnostic criteria outlined in the DSM-5. This is used around the world to classify mental disorders and is regularly updated, DSM-5 being the most recent edition. Diagnostic criteria for ADHD in The International Classification of Diseases (ICD-10) (a type of classification used by the World Health Organization as well as the NHS) are also used but less widely.
To be diagnosed with ADHD, a child must have six or more symptoms of inattentiveness, or six or more symptoms of hyperactivity and impulsiveness. A child must also fulfill other criteria, for example they must have:
- been displaying symptoms continuously for at least six months
- been showing symptoms in at least two different settings – for example, at home and at school
- symptoms that make their lives considerably more difficult, on a social, academic or occupational level
Adults are harder to diagnose because there is no definitive set of age-appropriate symptoms.
If a GP suspects a child may have ADHD he or she will be referred to a specialist for a more detailed assessment.
Where is the new article published and who wrote it?
It is by researchers and academics from Bond University and the University of Queensland, both in Australia and from University of Groningen in the Netherlands.
What does the article say?
The article says that diagnoses of ADHD have risen steeply over the past decade, partly in response to concerns about underdiagnosis and undertreatment. In parallel, prescribing rates for commonly used drugs such as methylphenidate (Ritalin) have also increased, in the hope that treating more people with ADHD will improve their quality of life.
In the UK for example, prescription of these same medications increased twofold for children and adolescents between 2003 and 2008 and fourfold for adults.
The authors point out that about 86% of children diagnosed with ADHD are described as having “mild or moderate” disorder, yet the DSM-5 and other guidelines do not include any definitions that differentiate mild or moderate from severe ADHD. (In the UK, NHS guidelines define mild but not moderate ADHD). While severe cases are obvious, there is a risk of subjective opinion varying about less severe cases.
One important cause of increasing diagnosis, they say, are the changes to the diagnostic criteria for ADHD. In recent editions of the DSM, the definitions of ADHD having been successively broadened. They predict that prevalence is again expected to rise with the adoption of DSM-5, which further widens the definition of ADHD.
These changes are a cause for concern because they increase the risk of confusing ADHD with normal development processes, they argue.
Other factors which may lead to over diagnosis include commercial interests – for example, they report that among the group advisers for ADHD on DSM-5, 78% disclosed links to drug companies as a potential financial conflict of interest. Patient advocacy groups are often financially supported by drug companies and are not immune from potential bias either, they argue.
The potential harms of over-diagnosis include the “unnecessary and possibly harmful” treatment for some individuals. Medications for ADHD can cause adverse reactions such as weight loss, liver problems and thoughts of suicide, while the long term effects on growth are unknown.
In addition the ADHD “label” may cause psychological harm and lower academic expectations and achievement.
They also argue that reducing the threshold for diagnosing ADHD “devalues the diagnosis in those with serious problems”.
What recommendations does it make?
For cases of mild to moderate ADHD they call for a more conservative, stepped approach to diagnosis, similar to that recommended by UK guidelines, to help reduce the risk of overdiagnosis. These advocate a watchful waiting period of 10 weeks, referral to a parent training programme (without the need for a diagnosis), and then referral to secondary care if symptoms do not improve. The goal is to reduce unnecessary diagnoses without risking undertreatment of those who really need psychiatric help.
They make the case that medication should be a ‘treatment of last report’ in most cases; only used when a child (or adult) fails to respond to other types of treatment.
What evidence is this report looking at?
The article is not a research paper but an opinion piece, based on references to diagnoses of ADHD, prevalence of ADHD, drug prescription rates, and changes in the definitions of this disorder.
What about the UK?
As the authors point out, the UK guidelines (PDF, 217Kb) from the National Institute for Health and Care Excellence (NICE) already recommend a “stepped” approach and that psychological treatment is given priority over drug treatment.
How accurate is the media’s reporting of the study?
Reporting was fair, with both The Independent and the Mail reporting comments from an independent expert in the UK.
This is a well written and argued piece. But it should not be taken as a summary of expert consensus on the current state of thinking about ADHD.
Individual views by experts in the field vary widely. Many argue that the increase in prescriptions is not due to overdiagnosis, or drug company lobbying, but is driven by a better understanding of the condition.
As with many complex topics, there appear to be no simple answers about the best way to care for people affected by ADHD.
If your child, or yourself, is affected by the condition, then your best option is to find out as much as you can about the condition so you can make an informed decision about treatment choices.
The NHS Choices A-Z topic on ADHD provides a useful starting point about learning more about the condition.