James Scott

THE proposed diagnostic criteria for attention deficit hyperactivity disorder to be included in the next edition of the Diagnostic and statistical manual of mental disorders have attracted media attention and some criticism.

Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental syndrome characterised by inattention, impulsivity and hyperactivity. In DSM-5, due to be published in May 2013, an ADHD diagnosis requires that “symptoms have persisted for at least 6 months to a degree that is inconsistent with developmental level and that impact directly on social and academic/occupational activities”.

But it is the symptoms of ADHD proposed by the DSM-5 that have attracted the most criticism. For example: “Finds it difficult to resist temptations or opportunities, even if it means taking risks (A child may grab toys off a store shelf or play with dangerous objects)” is reported to be such a common childhood behaviour that it is invalid as a symptom of ADHD.

The criticisms of the DSM-5 criteria for ADHD arise for several reasons. First, DSM-5 continues to dichotomise mental disorders as either present or absent.

Doctors know that mental health problems occur on a continuum in the population and the exact threshold where a person meets criteria for a disorder is debatable.

Many children have attentional weaknesses, and impulsive and hyperkinetic behaviours. Whether these cause impairment will depend on the expectations of those around them and the environment in which they live. For example, a hyperkinetic child living in an apartment in the city is far more likely to be considered “impaired” than the same child growing up in a rural setting.

This dichotomisation of the continuum of human experiences is a widely recognised weakness of the DSM classification system.

A second source of criticism of the DSM is that its checklist of symptoms can easily be misused and misquoted by people who lack clinical experience. The checklist for ADHD, when applied to children, is very non-specific. Many of the symptoms do occur in many children.

However, the requirement that relevant symptoms are present for 6 months or more, along with the number of symptoms and the caveat of impairment, help reduce the likelihood of overdiagnosing children with ADHD.

Doctors who undertake a detailed history and examination of a child and consider information from parents and school can identify those children struggling with developmental milestones.

Perhaps the greatest problem for psychiatry is the use of symptoms alone to diagnose illness. Psychiatry remains a very inexact science as it does not have genes, biomarkers, or structural or functional brain or electrophysiological changes to confirm a diagnosis.

Although there have been great advances in neurophysiology and neuroanatomy, the brain continues to guard its secrets carefully. In the future, translational research from animal models may be the key to unlocking some of the mysteries of the brain.

The diagnosis of ADHD should be made judiciously, following careful consideration of all available information. In addition to a detailed clinical assessment of the patient and their family, reports from school or work, educational and psychometric assessment and the use of second opinions from specialist colleagues are all valuable aids in the diagnostic process.

Once made, the diagnosis of ADHD will stay with the patient for an extended period of time and medical practitioners should be careful in reaching their conclusions.

Although the DSM-5 has many of the same limitations as previous editions, it is useful to complement rather than replace astute clinical judgement.

Dr James Scott is a consultant psychiatrist at the Royal Brisbane and Women’s Hospital and the University of Queensland Centre for Clinical Research. Mr Michael Duhig is a research officer at the Queensland Centre for Mental Health Research.

Posted 5 September 2011