ADHD and ASD part of the same?

When I was training in paediatrics, most of the behavioural disorders taught about and seen were lumped into Attention Deficit Hyperactivity Disorder (ADHD), with a few of severely affected children having Autism Spectrum Disorder (ASD), but never the twain would meet.


As I grew into my paediatric consultancy, I began to see that it was not always that easy to differentiate between the two.  Given ASD is a spectrum of symptoms, I began to question what I was hearing from families about presentations that seemed to have some overlap with ADHD.  Recently I have reviewed the development of these two disorders to help clarify my interpretation of what I see clinically, and how it fits within the DSM diagnostic criteria as this is now used as the standard in most of the world.


In 1968 overactive children were diagnosed with Hyperkinetic Reaction of Childhood under the DSM-II criteria.  In 1980 the focus was on poor attention and impulsivity and with the release of the DSM-III this was renamed Attention Deficit Disorder (ADD).  Later, in the revision or DSM-IIIR, terminology changed to include hyperactivity again, or ADHD.  In 1994 as DSM-IV was released, ADHD now came with three subtypes of; inattention, hyperactivity/impulsivity and combined.


It wasn’t until 2013 that DSM-V was published with some fine tuning of the definitions of ADHD, moving away from subtypes and focusing more on presentations recognising that the symptoms of ADHD are fluid and part of a continuum, more like the spectrum of ASD symptoms.  The other important step was the removal of ASD as an exclusion, so that now both diagnostic labels (ADHD and ASD) are able to co-exist.


What this has demonstrated to me, is that these categories of behavioural symptoms are fluid, cross over and don’t always fall into discrete little diagnoses.  Symptoms are subject to the environment, which is changing and developing within our society that is constantly reshaping its definition of normal.  The DSM is a useful tool to help us clarify what is going on and when intervention may be helpful, but children remain their own distinct personality.


It is therefore my opinion that close questioning of the symptoms presenting and particularly their environmental context which will inform diagnosis.  Like anything new (ASD and ADHD co-existing) there is a lag time for professionals to catch up within the medical, but also educational field.  However, I still believe if we have a patient focused diagnostic approach, we can help to address these symptoms.  The label or diagnoses used to describe what is happening in my view does not change the patient centred approach.  It may however help us to gain understanding about what is happening for that child, or access to support in education or health.



People are complex and come from even more complex environments.  Let’s face it, none of us likes to be fully pigeonholed into a box, though we do like to find our tribe to help us understand how we function and make sense of our world.  Exercising caution before attaching a label is important, the key therefore is in careful listening and considering the wider context.  Sometimes it is just a case of watching or waiting, and in our impatient society that is never easy.


So, it is not straightforward separating out ADHD from ASD, in fact they may be extremes of behavioural traits all on the same continuum.  I am sure the next DSM will have further changes, but people remain the same.