Note: This is mainly put together from blog posts from 2012, but since no-one read those, I thought it was worth putting the stuff out again.
There has been a peak of interest in over-diagnosis recently, for instance http://theconversation.edu.au/over-diagnosis-the-view-from-inside-primary-care-8889/ It’s all been interesting stuff, but what I think is not always made clear is where the specific harms of over-diagnosis are to be found. ADHD has been at the forefront of this debate, which dovetailes with a general critique of psychiatric diagnosis, so this seems a good place to start.
We’re not saying that there is a distinct biological process going on here, like there is in Parkinson’s, for instance. Most people in the field think that ADHD people lie on a spectrum from the ‘normal’, with no ‘clear blue water’ between the two. That’s not to say that ADHD doesn’t have a biological basis, we’re finding stuff all the time, but usually by comparing a “definitely not ADHD” population with a “definitely ADHD” one. Things are much less clear in the grey, messy clinical world.
I believe that for the children whose ADHD-ishness (technical term) is sufficiently pervasive and impairing to cause them problems socially and in their day to day function, then it is of benefit. There are effective interventions available, both pharmacological and non-pharmacological.
When I commented on Twitter that my patients seem to be less stigmatised after they receive an ADHD diagnosis than before, other people were skeptical. This interested me, so I thought I would record my thoughts on this.
Here’s my narrative:
When kids arrive at the point of being assessed, they have typically been labelled as ‘naughty’; they are frequently described in school reports as ‘choosing to behave’ in a particular way. Their behaviour is ascribed by schools to their parents’ lax discipline or other shortcomings, about which schools can do very little.
When I explain ADHD, I talk about the distribution across the population of ‘ADHD-ishness’, at the top end of which the child starts to run into problems, an
Once the diagnosis is made, I find that teachers see the chiIld in a more positive light, as finding it hard to conform rather than ‘choosing’ not to, and as someone who can be helped to engage better with education. Parents feel relieved of the burden of having caused the child’s difficulties, although they do now take on a significant therapeutic responsibility (which not all are delighted by….). Children also seem to benefit from the positivity.
It’s important to note that none of this requires medication- i prefer to discuss this after other interventions have been put in place.
There is another narrative, of course:
Child makes trouble at school, and is sent to a paediatrician for ‘sorting out’. Checklists seem to show ADHD, so the child is told they have an incurable brain disorder and needs to be on medication for life. Teachers give up on him as a lost cause. Parents understanding is that there is something ‘wrong’ with the child, nothing to do with them, and that they have no responsibility for helping the child, as the medication will take care of it.
I’m not sure that this second narrative is entirely wrong, and unfortunately it may be highly accurate in some cases. I try hard to avoid the pitfalls of the second narrative, but I’d be interested to know anyone else’s thoughts/ experiences on this.
So yes, there are potential harms in over-diagnosing ADHD, but they might not be the ones that those arguing against increasing diagnosis rates are thinking of.
Why does this matter? Well, I wanted to build an robust argument for not broadening diagnostic boundaries, as DSM-V seems to intend. And because I think that we will need it in the next few years to stop the UK drifting towards the US model for ADHD.
So how do we keep diagnosis rates at a reasonable level? I’m going to be a bit didactic for the sake of brevity. Apologies if it makes me seem a bit of an arse. Please feel free to disagree.
1. Start with an open mind
I slightly wince when services set up ADHD diagnostic clinics; doctors sometimes forget that we are as prone to cognitive bias as anyone else, and seeing a patient who may have ADHD in an ‘ADHD clinic’ seems a good way of ensuring over-diagnosis. I’m a bit of a purist about this- I won’t allow ADHD-specific questionnaires to be completed until we’ve had a chance to see the child- some schools and some parents are keen enough on the diagnosis already, without allowing them to present it to us as a fait accompli!
2. Beware incentives to diagnose
The most obvious incentive occurs when the person who is paying for the assessment wants a diagnosis. I’m not making allegations, but I’ve never known a family go private and not get the diagnosis that they want, even if several NHS teams have denied them. It seems possible that this is an engine of the US explosion in diagnosis.
But even within the public sector, we need to be careful. If a child needs you to keep them on in your clinic, managers should not make this dependent on them having a diagnosis. Obviously if, say, the government farmed out ADHD services to private contractors who had a clear interest in diagnosing, medicating and following up large numbers of children, that would be a terrible in so many ways… but it’s never going to happen SO THAT’S OK, and anyone who accuses the government of the break-up and privatisation of the NHS is scare-mongering.
Outside health, education authorities need to bear in mind the clear central guidance that provision should be based on need, not diagnosis. Finally, decent quality parenting intervention should be universally available, not just to diagnosed cases (as per NICE guidance).
3. Impairment not symptom counts!
I like criteria- they help keep everything consistent. But the DSM and ICD symptom checklists can contribute to over-diagnosis. Let’s look at the DSM on ‘Hyperactivity’ (you need 6 from this and impulsivity for diagnosis)
- often fidgets with hands or feet or squirms in seat
- often leaves seat in classroom or in other situations in which remaining seated is expected
- often runs about or climbs excessively in situations in which it is inappropriate (in adolescents or adults, may be limited to subjective feelings of restlessness)
- often has difficulty playing or engaging in leisure activities quietly
- often talks excessively
- is often ‘on the go’ or often acts as if ‘driven by a motor
Useful questions, every one. But what does ‘often’ mean here? These are behaviours that many children exhibit from time to time, and it seems to me that an exasperated parent may well answer these in the positive even if they are not the main problem causing the exasperation. So a consistently defiant and slightly lively child can look on this checklist like someone with ADHD.
What I think is important is to try to quantify the degree of ‘ADHDishness’*, this is not easy, but rating scales combined with careful qualitative interpretation of reported behaviours helps. You then look at impairment (can they go to the supermarket, go on a bus, eat a meal with their family etc) and if:
a) the ADHDishness is real, significant (I prefer to see 2 standard deviations above the mean) and inconsistent with developmental level.
b) the impairment is significant, long-standing and pervades several settings
c) the impairment can be attributed to the ADHDishness
Then I’m happy to diagnose.
*: I know this is a) not a single dimension and b) much more complex than I make out.