A dual diagnosis of autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) — what are the implications?

Kathy carter
Jun 18 · 8 min read

A dual diagnosis of autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD), both neurodevelopmental differences, is becoming more prevalent now, due to clinicians’ ability to diagnose both conditions under the latest diagnostic criteria. (The older DSM-4 for example specified that an ASD diagnosis was an ‘exclusion criterion’ for ADHD, thereby limiting research in the field — source — Leitner.) The reason why the two conditions may co-occur is unknown, however there’s thought to be some common underlying etiology, as yet unconfirmed.

It does require a very experienced clinician or multi-disciplinary team to carry out the assessment and subsequent diagnosis, as the two conditions presenting together can make diagnosis much harder. But why is it harder to spot an individual with an autism spectrum condition (ASC) AND ADHD — for example, if you’re a teacher or family member? Here’s a theory — is it as if the two extremes of each condition can be softened, or can become less noticeable to outsiders? (Inside, the challenges and conflicts the individual experiences can of course be considerable — but the outer ‘presentation’ can perhaps sometimes appear more typical.) An example of this theory is that autists may typically prefer sticking to their routines and their limitations, whereas those with ADHD may be more impulsive and fearless — the two extremes can potentially mean the individual’s choice at a given time (eg. to climb a high and unknown tree) sits more in the middle; they may be less likely to avoid the activity as it is out of their ‘safe’ and ‘known’ remit of ‘sameness’ (relating to ASC), but also less likely to take a big risk (relating to ADHD / impulsivity).

Autism may be missed if an ADHD diagnosis is given first

It is said that some children with both conditions are unfortunately having their autism missed, if they get an ADHD diagnosis first. In a study in the journal ‘Paediatrics’, researchers looked at around 1,500 autistic children. They found that those who got an ADHD diagnosis before an autism diagnosis were diagnosed with autism an average of three years later than those who got the autism diagnosis first. They were 30 times more likely to get the autism diagnosis when they were aged six or older. (Source — Harvard University).

Let’s look at the key factors of each condition — autism and ADHD

(1)ADHD is defined by impaired functioning in the areas of attention, hyperactivity, and impulsivity. Often, children with ADHD have difficulty focusing on one activity or task; they may be easily distracted; they are often physically unable to sit still. The ‘attention deficit’ wording may be misleading, as this element could be described as an ‘interest’ deficit — eg. the individual can hold their attention easily on something, if they’re interested in it. As with ASC, children with ADHD often have difficulty moving their attention to other activities, when they are asked to do so. (Source — Children and Adults with Attention-Deficit/Hyperactivity Disorder, or CHADD).

(2)Autism is characterised by social and communicative dysfunction, restrictive-repetitive behaviours and sensory challenges. Children with ASD are most likely to have hyper-focus, and may be unable to shift their attention to the next task. They are often inflexible when it comes to their routines, with low tolerance for change. Many are highly sensitive or insensitive to sensory input, like light, noise and touch. They may ‘stim’ eg. make gestures such as repeated arm flapping, or oral stims like tongue sucking. (Source — CHADD). (Read our blog on stimming below.)

(3)Autistic symptoms are said to be more ‘stable’ than those of ADHD behaviours, which show greater variability in their presentation. (Source — Pourcain et al. (2011). It would therefore be normal for someone diagnosed with both autism and ADHD to present completely differently on different days, and of course to feel very different on different days, depending on which condition is dominant and what external factors are present (eg. nutrition / sleep / sensory challenges).

(4)Both conditions/disorders affect the central nervous system, which is responsible for movement, language, memory, and social and focusing skills. (Source — CHADD).

(5)Studies show that up to 50% of individuals with ASD also manifest ADHD symptoms (particularly at pre-school age). Similarly, estimates suggest two-thirds of individuals with ADHD show features of ASD — source — Leitner.)

(6)Anxiety and mood disorders, although highly prevalent in those with ASC alone, are even more prevalent in individuals who have ADHD. (Source — Lipkin et al).

A dual diagnosis

The issue in terms of diagnosis is that both autism and ADHD often include difficulties in attention, communication with peers, impulsivity, and various degrees of restlessness or hyperactivity. Both conditions can cause significant behavioural, academic, emotional, and adaptive problems in all settings.

However in our minds here at Spectra.blog, having both conditions does not necessarily equate to twice the challenges. Maybe just a different set of challenges! There are perhaps positives to be gleaned from having autism AND ADHD, over having autism on its own, in terms of some of the restrictive and limiting elements of autism being potentially reduced at certain times, when the more impulsive and sociable elements of ADHD are dominant.

Warding off anxiety

We must be upfront. It is proposed that there’s a risk for ‘increased severity of psycho-social problems’ (depression and anxiety etc), with a dual diagnosis of ASC and ADHD. (Source — Gadow et al., 2004; Yerys et al., 2009). However, having an understanding about the conditions at an early age (for the individual) surely helps families and educators (and the autist themselves) to manage their challenges, in order to ward off such problems? (Eg. talking therapies like CBT, mindfulness techniques, dietary support or management, and skills training to help cope with daily life, eg. ‘social skills’ training via a school programme.)

In a study titled ‘Anxiety and Mood Disorder in Children With Autism Spectrum Disorder and ADHD’, it was reported that anxiety disorder and mood disorder, while very common in ASD, are even more common when children also have ADHD. Knowing in advance that anxiety and mood disorders are a big risk factor for individuals with ASC and ADHD means interventions and supports can be given in advance, to help promote good mental health. Adaptions can be made and demands can be reduced, in order to prevent anxiety in the individual. It is a good idea for the autist themselves to gain an understanding of their conditions, how they present on different days (eg. which condition is more dominant, and how that feels), and also what external factors (food, sleep etc) are contributory.

Medication

Medication to help readdress the chemical imbalances of ADHD in older children or adults may be suggested/prescribed, however it is said to have the potential to be LESS effective for individuals with ASC AND ADHD, and may cause more side effects, including social withdrawal, depression, and irritability, as opposed to when the medications were used to treat ADHD alone. (Source — CHADD). The National Institute for Health and Care Excellence (NICE) recommends that the first steps in treatment for ADHD for young people include help with behaviour and stress management as well as educational support — children under school age should not be given medication for ADHD, they advise. (Source — NAS.)

Does having ASC and ADHD ‘buffer’ the conditions somehow?

We would have to collate opinions of individuals with both conditions, in order for us to comment fairly (and we actively invite them to — if you have autism and ADHD, please comment, or get in touch!). But surely this duality of ASD and ADHD has the potential to provide some kind of ‘buffering’ effect, in terms of reducing extreme or unsafe behaviours? In ADHD children, when the hyperactivity and impulsivity would be more noticeable, this ‘buffering’ element could perhaps be beneficial to an individual’s safety; eg. if the impulsivity of ADHD was offset somehow by a more rational and logical mindset.

Having both conditions, autism and ADHD, can however mean that outsiders like educators and extended family members can’t initially see that the behaviours the person has are atypical. Eg. a dual diagnosis of ASC and ADHD can presumably mean the individual could present more like a neurotypical (NT or non-autistic) person. It doesn’t mean they feel NT inside of course, or that their challenges are reduced.

ADHD, like ASD, is widely said to be a lifelong condition, however the characteristics may alter with age, eg. the hyperactivity element is said to be much more common in children than in adults. Some adults report a large decrease in symptoms of ADHD as a person ages, however this could be due to their own management of their challenges. This reduction in overt signs leads some experts to propose that ADHD isn’t lifelong; however the general consensus is that ADHD DOESN’T GO AWAY.

What is the benefit of clinicians being able to diagnose ASC and ADHD?

A dual diagnosis of ASC and ADHD potentially allows for more efficient clinical management of such individuals, and ‘clears the way for a more precise scientific understanding of the overlap of these two disorders’ — source — Leitner.

As we have described, it allows the individual to gain an understanding of their neurology, in a way that many NTs do not have — after all, anxiety and depression are prevalent across the population, eg. across all neurologies. Perhaps understanding one’s own neurology, in the way that many autists do, is a benefit in terms of safeguarding mental health and knowing how to administer ‘self-care’? (Read our blog on the Spoons Theory, for more info).

Lining toys up can be linked to autistic traits.

If any parent or educator is concerned that a child is exhibiting disproportionate levels of anxiety, plus a kind of ‘double-sided personality’, with moods that are very cyclical, as well as the usual signs of autism like social and communicative issues, repetitive behaviours (like lining toys up, in our photo),and sensory challenges, it may be worth investigating the possibility of a co-morbid ADHD diagnosis too.

Or at least, initially keeping a diary of signs and behaviours, and external factors.

A little disclaimer — here at Spectra.blog we don’t claim to be experts about Autism Spectrum Neurologies / Disorders / Conditions.

The information we post here is based purely on our own exposure and experiences. We’d also love your feedback on our posts!

Read more on co-morbid autism conditions here -


Originally published at Spectra Blog.

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