Why is ADHD so under-diagnosed and treated?

The child and adolescent component of the 2000 National Mental Health Survey reported a rate of Attention Deficit Hyperactivity Disorder (ADHD) of about 6%, essentially identical to a recent analysis of data from throughout the world.Yet the highest rates of medication for ADHD in Australia are no more than about 1.5%. What is happening to the other 75% of young people whose lives and those of their families are impaired by ADHD? Are they even being identified, far less receiving behavioural or other intervention?

Even worse, have their families fallen victim to some of the profitable programs which claim to "cure" ADHD?  For example some 12,000 Australian families have paid their $5,000 for the now bankrupt Dore program, marketed as a non-drug approach to ADHD and reading disability among other disorders.

There is no doubt the first form of intervention except in the most serious cases should be behavioural, but where are families going to find the necessary expert and can they afford her or him? And can they be sure there is a good evidence base for the intervention they are receiving?

Misconceptions

Firstly, there are many common misconceptions about ADHD, one of which is that it is a "modern disease".  It was actually really well described by an English paediatrician, George Still back in 1902 though he called it "defective moral control"!

Secondly, ADHD is difficult to diagnose as there is no biological test for it.  In fact there is no biological test for any child or adult behavioural disorder and ADHD is actually probably easier to diagnose than depression, which no one would argue exists. The symptoms of ADHD are external and easy to see. The symptoms of depression are internal and often may be unknown to others.

The third common complaint is that ADHD does not exist as all of us sometimes show common symptoms of ADHD such as being inattentive or fidgeting. That’s true, because ADHD is a continuum through the population as are symptoms of depression or our blood pressure. But we have to draw the line somewhere in terms of deciding when someone needs treatment for their depression or high blood pressure. ADHD is no different.

In fact when the most recent diagnostic criteria for ADHD were developed in the USA in the mid-1990s, they set the bar pretty high in terms of the number of symptoms you had to have. Essentially all these people would have impairment at home or school or work or in personal relationships, etc. You could say the threshold is arbitrary but we accept many such decisions – try using the same argument with the police officer who stops you for speeding or being over the blood alcohol level! These cut-offs are equally as arbitrary.

‘Good news is no news’

Is ADHD being over-diagnosed? There have been very few reports in the media on the NSW audit of ADHD which came out in February 2008. Asking clinicians about their diagnostic practices and actually going to some 30 practices and going through their records showed that almost all practitioners were thorough in their assessment. This got no media coverage while if it had been the opposite and negative about ADHD, it would have been on the front page of every paper! Good news is no news.

What causes ADHD? 

Since about 1990 I have been fortunate enough to have worked with Professor Florence Levy from Sydney, developing the Australian Twin ADHD Project which is now one of the world’s largest studies into the causes of ADHD. I have worked in the area of behaviour genetics since 1968 and ADHD would have one of the largest genetic components I have ever encountered. This is not just our work but has been found throughout the world.

There have been specific genes identified for ADHD, mainly involving dopamine, the chemical messenger in the brain which is most affected by stimulant medication. Many of the environmental risk factors which have been found to contribute to ADHD may actually reflect the genetic background. So while maternal smoking during pregnancy is one such factor, is it the nicotine or the fact that only women who are high risk-takers continue to smoke during pregnancy? And people with ADHD are such risk-takers. US studies show they have much higher rates of everything from traffic accidents to teenage pregnancy. Obviously this has implications for parent training programs, if parents have problems with disorganisation or impulsive behaviour.

One of the main outcomes of our work on ADHD has been a much greater appreciation of comorbid conditions, the other problems which people with ADHD may have. Many have learning problems which pose extra challenges for the education system. Many are what used to be called clumsy – the new term is developmental co-ordination disorder. And one consequence is poor self-esteem. You are not doing well at school or at sports and your inattention to social cues or your habit of butting-in to conversations because of your impulsivity doesn’t get you many friends.

Families deserve a better deal

What of adult ADHD? The diagnosis is more controversial though improving. Not helped by Time Magazine which claimed Bill Clinton has ADHD – which is one explanation for some of his indiscretions! We are now recognising that some, perhaps half of those with ADHD do not grow out of it and there is increasing evidence that they may not succeed in their careers as well as other people and their relationships may be subject to more tension.

Many people relate ADHD to substance abuse and that is true. A recent Dutch study indicated a rate of some 20% among substance abusers and one of my students found a rate closer to 45% in those using the needle-exchanges in Perth and who are therefore pretty serious users. But what is rarely pointed out, is that there have been 11 studies that showed there is one way to reduce this risk – take stimulant medication. Such medication does reduce the risk of starting to abuse licit or illicit substances and actually helps get the person back on a more even keel to approach the challenges in their life.

Families with ADHD deserve a better deal than they are get

Families with depression get great support from the community, the media and especially politicians. Jeff Kennett is a great advocate for the understanding of depression. Those with ADHD deserve the same and to live in a world where there are more votes in supporting well-evidenced practice in the diagnosis and management of ADHD than in bagging the entire disorder.

Professor David Hay is a professor of psychology at Curtin University of Technology, WA. He is a member of the group drawing up new national guidelines on ADHD, but is writing here in a personal capacity. Professor Hay discloses that he accepts travel expenses from pharmaceutical companies in order to speak at conferences, in adherence with his employer’s guidelines, but does not accept fees from such companies.

(Source: ADDults with ADHD (NSW) Inc: January 2009.)