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PM - Research project studies ADHD diagnostic methods
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http://www.abc.net.au/pm/content/2003/s1013097.htm]
PM - Thursday, 18 December , 2003 18:42:00
Reporter: Nance Haxton
MARK COLVIN: Even in the medical community, the question of Attention Deficit
Hyperactivity Disorder is hotly debated. Some say the disorder is increasingly
prevalent among Australian children, some say it's just being diagnosed more
often, and there's been fierce controversy over whether drugs such as Ritalin
are being over-prescribed as a result.
Now a new national research project may go some way to settling the arguments.
At present, doctors have to rely heavily on their observation of a child's
behaviour when they diagnose ADHD. But the research project aims to find a more
reliable diagnostic method, based on biological functions in the brain.
Associate Professor Richard Clark from the Flinders University School of
Psychology spoke to Nance Haxton.
RICHARD CLARK: In the case of ADHD what you see essentially are children who
have disruptive behaviour, report problems with memory and concentration, and
the ability to attend… focus their attention in a solid and consistent way.
The trouble is that in doing a formal clinical diagnosis of ADHD, those sort of
presentations are consistent not only with ADHD, but they're also consistent
with other sorts of disorders.
And the difficulty is to try and find a sensitive and specific marker or set of
markers of ADHD that are biologically based and which will allow you to say
with a high degree of reliability whether or not the behaviour you observe is
in fact ADHD or whether it's something else.
NANCE HAXTON: Certainly that's been probably one of the controversial aspects
of ADHD in the past years, is the emphasis on Ritalin and other amphetamines as
a treatment. How will you be looking at that?
RICHARD CLARK: The problem with the use of Ritalin and other amphetamines in
the treatment of ADHD is the concern that the drugs may be being used in cases
of misdiagnosis. And of course with the current clinical methods and
behavioural methods of assessing, it's very difficult to be clear.
It is a difficulty for clinicians and most clinician I'm sure will acknowledge
that, and I'm sure most clinicians will be very keen to get more discriminating
measures of dysfunction.
So the problem with treatment with stimulants is not that they don't work in
the right cases, in fact they seem to be very effective in the right cases. The
trouble is using them in the wrong cases.
And so what we're hoping to do is look at the effect of treatment, Ritalin
treatment on children who are diagnosed with ADHD, and look at the effect
Ritalin has on their brain functioning as well as behavioural functioning, and
see how that compares with the brain and behavioural functioning before they
started that treatment.
NANCE HAXTON: Could it be that the treatment to a degree is actually masking
the actual… the underlying cause of that behaviour?
RICHARD CLARK: Well, certainly, if it's the case that Ritalin, or whatever
stimulant is being used modifies aspects of brain function that are not
abnormal in the first place, then a reasonable conclusion would be, well, what
we're doing is we're modifying other aspects of brain function to compensate
for those that are not working properly. That would be one interpretation you
could make. And perhaps that would be a matter of concern. I suspect it might
be.
NANCE HAXTON: At this stage is it too soon to possibly look at what the
conclusions may be as to what exactly ADHD is?
RICHARD CLARK: Well, it's certainly too soon now, probably in about 18 months
time when we've completed the study, yes, we'll be able to make more definitive
statements. I mean, part of the issue is the extent to which ADHD is a single
thing, or whether it's a syndrome of brain dysfunctioning.
I mean, this is the case of many psychopathologies. I mean, if you look at
schizophrenia that is not just one thing, it's a cluster of different problems.
And it's likely to be the case it's the same sort of thing in ADHD. In fact,
that's already been recognised by a number of sub-types of ADHD in the clinical
categorisation.
So part of what we're really hoping to get out of this study is to see if we
can definitively identify different sub-groups in ADHD and to look at the
differential treatment of Ritalin in these different sub-groups.
In some sub-groups the treatment may work, in other sub-groups it may not. And
that's going to be very, very important information for the clinician in
deciding about what treatment program they would use for their patients.
MARK COLVIN: Associate Professor Richard Clark, from the Flinders University
School of Psychology, with Nance Haxton.