Why you need to know about conditions that often show up with ADHD

Why you need to know about conditions that often show up with ADHD

ADHD often shows up with an entourage of co-occuring conditions that can complicate diagnosis and treatment. Common co-occurring conditons include autism, Generalised Anxiety Disorder, Specific Learning Disorders, epilepsy, eating disorders and migraines.

ADHD & its entourage

There’s an old joke that if you just have an ADHD diagnosis then you’re not looking hard enough.  You see, it’s more common than not to have ADHD and one or more conditions to manage.

ADHD often shows up with an entourage of co-occurring conditions. Or as a psychologist called them “groupies”, who are going to hang around for the long haul. 

Ughhh, who else hates the word co-morbidities? It just sounds so … morbid?  Yes, let’s not use that one hey?  Co-existing or co-occurring conditions … much better in my humble opinion.

Anyway, co-occurring conditions are conditions that are present with other conditions. 

So you're telling me there's more?

Yes, along with our beautifully neurodivergent brains we can often experience other conditions.  This is not to freak you out that you have even MORE to deal with.

Instead knowledge means you can be aware of all the links and how they interact.

It can also help you to advocate for your child to ensure all co-existing conditions are identified and supported, quickly.

As Neurodiversity Campaigner and Chair of Developmental Disorders at the University of South Wales Professor Amanda Kirby writes: 

“Services often operate in different professional services.  The diagnoses people receive may often reflect the professionals that they have seen, rather than the actual difficulties that they may have.  

“Even if all of an individual’s diagnoses are, eventually made, working in silos means delays may be exacerbated”.  


Common co-occuring conditions with ADHD include anxiety, autism and Developmental Coordination Disorder (DCD).

Common co-occurring conditions

This is not an exhaustive list, but here are some of the more commonly occurring or recognised conditions that can be present with ADHD:

♾️ Autism

♾️ Auditory Processing Disorder

♾️ Developmental Coordination Disorder (DCD, also known as Dyspraxia)

♾️ Developmental Language Disorder (DLD)

♾️ Generalised Anxiety Disorder

♾️ Depressive Disorders

♾️ Specific Learning Disorders (e.g. Dyslexia, Dysgraphia, Dyscalculia)

♾️ Tic Disorders (including Tourette’s Syndrome and Chronic Tic Disorder)

♾️ Postural Orthostatic Tachycardia Syndrome (POTS)

♾️ Ehlers-Danlos Syndromes (EDS)

♾️ Hypermobility Spectrum Disorders (HSD)

♾️ Congenital Heart Disease (CHD)

♾️ Feeding and eating disorders including Anorexia Nervosa, Binge Eating Disorder (BED), Bulimia Nervosa and Avoidant Restrictive Food Intake Disorder (ARFID)

♾️ Migraines

♾️ Vision Loss

♾️ Hearing Loss

♾️ Sleep Disorders including Insomnia

♾️ Gastrointestinal Disorders (GI) including constipation, diahorrea, not eating, nausea, painful bowel movements, stomach aches and vomiting

♾️ Epilepsy/seisures

♾️ Obesity

♾️ Oppositional Defiant Disorder (ODD)

♾️ Obsessive Compulsive Disorder (OCD)

♾️ Bipolar Disorder

♾️ Substance use


This great graphic from Professor Amanda Kirby shows the many linkages between neurodivergent characteristics and conditions.

Why it can help to be in the know

Conditions like anxiety or Specific Learning Disorders you may think, ahhhh that makes sense.

Others, like Ehlers-Danlos Syndromes or Hypermobility Spectrum Disorders you may not have heard of, or considered the link with ADHD.

Here’s an example of why it can be helpful to understand the possible co-occurring conditions and their impact on your child.

The hypermobility example

Lots of kids are very bendy.  Some people have what’s called benign hypermobility – they’re bendy but without pain or functional issues.

Those with Hypermobility Spectrum Disorders (HSD) have a disorder of the connective tissue, which is not just around your joints but is ALL through your body, including your gastrointestinal system (GI).

HSD can be linked to constipation and slow transit of fecal matter through the GI system causing stomach pain.  So those stomach aches – are they anxiety, school refusal or are they related to the HSD?  

Those headaches or migraines – are they anxiety?  Or are they vascular or abdominal migraines again linked to the connective tissue through the GI system?

Are those after school meltdowns challenges around emotional regulation?  Or are they the sign of a child whose body is so fatigued because it has been working that much harder than other students just to keep them upright at a desk or on the mat?

Is the messy handwriting because they struggle to hold and manipulate a pencil as their little hands are bendier than others? 

Why is this important?

Oh, I’m so glad you asked!  Co-occurring conditions can make diagnosis more complex: they can mask other conditions or be mistaken for ADHD.

They are often why it takes time and experienced specialists to unpack what is the primary condition and what may be secondary.

You see, some conditions like to hide behind others and may become more obvious once treatment is initiated.

I often hear parents describe how once their child commenced treatment for ADHD, their autism traits were more pronounced and obvious to them.  

You can download the poster that Clinical Psychologist Michelle Mitchelson presented at the 2023 AADPA Conference on "What is It Like to be an AuDHD-er? (Co-occurring autism)" from her website: moniquemitchelson.com.au

Conditions that can be mistaken for ADHD

Similarly, there are several conditions that can also be mistaken for ADHD including epilepsy, anaemia, thyroid conditions, hearing or vision loss.

You really don’t want to be waiting on a two-year waiting list to find out that what you thought was ADHD was actually low iron.

I kid you not.  It happens. 

Inattention, distractability, difficulty in initiating or completing a task, daydreaming, not paying attention.  

All sound like hallmarks of Inattentive ADHD right?  Well, they can also be symptoms of anaemia.  

A test that could have saved a 2-year wait

A local psychiatrist gave me an example of a child she saw who didn’t have ADHD.  What they did have was a thyroid condition that could have been picked up through a simple blood test.

Once that was treated, all the other symptoms and issues disappeared.  A great outcome, eventually.  But that child had waited a loooooong time to get to her. 

What a waste, in something that could have been picked and treated much, much earlier.   

And what a waste of resources for a psychiatrist to be the one to pick that up.  When that happens it delays that child getting the help they need while they wait to get to the top of a very long waitlist.

It also stops children who really need psychiatric help from accessing one of the few child and adolescent psychiatrists we have in WA.n

Pre-referral guidelines

Melbourne’s Royal Children’s Hospital publish referral guidelines that require GPs to complete an initial work up prior to referring children for development concerns.

They won’t accept referrals without this information.  

Given the referrals I have been sent it would probably be a great standard to enforce here too.  Although I’m not aware of it locally, but it may exist.

Too many referrals I see just say “Mum is concerned about ASD/ADHD, please review and provide opinion”.  

The RCH required initial work up includes: 

1. taking a history of the concerns, their onset and family history, 

2. a developmental and neurological examination, 

3. an auditory assessment (especially if there is speech delay) and

4. optometry or opthamology assessment if screening by the Child Health Nurse or GP are abnormal.

You can read the RCH pre-referral guidelines here.

What I suggest

So I suggest to any friends to get some basic tests done through their GP before or as part of their referral to a specialist.

Make sure the child can see, can hear and rule out thyroid conditions or low iron.  

You would be surprised how many have come back to me and said how low their child’s iron was and how once addressed all was OK.  

One poor Mum had worried that her daughter had Dyslexia, but again it turned out to be low iron affecting her ability to concentrate. 

Complicating treatment

Coexisting conditions can also complicate treatment.

Some co-existing conditions need to be stabilised before using ADHD medications.  

Some symptoms are from untreated ADHD and the impacts may fade away once the underlying condition is treated.

Some need to be treated together.

How some conditions interact

Anxiety for instance can be worsened in some children by stimulant medication.  It may need to be stabilised before stimulant medications can be trialled.

For eating disorders such as anorexia nervosa, some practitioners will not treat ADHD with stimulant medications until the eating disorder is stable for fear of suppressing appetite.  

Others believe that treating the ADHD actually helps with the treatment of the eating disorder, if ADHD is the primary condition.  

Similarly with substance abuse, which for many may seem counterintuitive to treat drug or alcohol abuse with stimulant medication.   

Victorian Psychiatrist Dr Diana Grocott is so convinced of the link that she suggests that we should screen every drug user for ADHD and screen everyone with ADHD for drug use.  

At the My Spirited Child WA ADHD Conference Dr Grocott said that while 4% of adults have ADHD, approximately 20% of substance users have ADHD.   

She said that most addiction services ignore ADHD.  Her perspective was that ADHD is not hard to treat and treating ADHD improves substance use disorder outcomes so why ignore it?


Treat ADHD first, then whatever is left

Some doctors believe that your treat the ADHD first and then treat whatever is left.  

In the case of Specific Learning Disorders, some suggest that the symptoms of these will melt away once the child’s ADHD is treated and they can concentrate in class.

I have to say, this does concern me a little because – what if they don’t?

Let’s look at the timeline.

1. Wait up to two years to get a diagnosis

2. Spend up to six months of titrating to a suitable medication and dose 

That equals up to 2.5 years … and then you decide the SLD is not fading away?

So then you need: six months of targeted intervention required before you can get an SLD diagnosis.  


Up to three years before SLDs are diagnosed and then supported through the required interventions and accommodations.

With so many students seeming to be referred around year 3 or 4 – often when academic expectations increase beyond their natural intelligence that has allowed them to previously get by – that means they could likely be entering high school without adequate foundational learning.  

Imagine the impact that’s also having on their self esteem.  

I figure that unless I was getting into a paed ASAP and starting treatment, I would be ruling in or out and starting support for SLDs just in case.  

I don’t think it could hurt, but waiting could.


Your doctor

As always, be guided by your treating doctor as to what is most appropriate for your situation.  

I’ve found it never hurts to do a bit of research myself, but make sure your sources are reputable and not the opinions of others from a Facebook group.  

Google Scholar can be a great place to start for free access to reputable medical journals.

Over to you

What’s your experience been of co-existing conditions?  Share your comments below.


Biderman, J. (2021). ADHD Comborbidity with Autism Spectrum Disorder and Burden of Traits of Autism Spectrum Disorder in ADHD. Journal of the Amercian Academy of Child & Adolescent Psychiatry, 60(105), 125-126. https://doi.org/10.1016/j.jaac.2021.07.504 


Bougeard, C., Picarel-Blanchot F., Schmid R., Campbell R., and Buitelaar J., (2021). Prevalence of Autism Spectrum Disorder and Co-morbidities in Children and Adolescents: A Systematic Literature Review.  Frontiers in Psychiatry, https://doi.org/10.3389/fpsyt.2021.744709


Glans, M., Thielin, N., Humble, M., Elwin, M., Bejerot, S. (2021). Association between adult attention defecit hyperactivity disorder and generalised joint hypermobility: A cross-sectional case control comparison.  Journal of Psychiatric Research,  143, 334-340,  https://doi.org/10.1016/j.jpsychires.2021.07.006


Keshen, A., Bartel, S., Frank, G. K. W., Svedlund, N. E., Nunes, A., Dixon, L., Ali, S. I., Kaplan, A. S., Hay, P., Touyz, S., Romo-Nava, F., & McElroy, S. L. (2021). The potential role of stimulants in treating eating disorders.  International Journal of Eating Disorders.  55(3), 318-331. https://doi.org/10.1002/eat.23650


Melbourne Children’s Hospital.  Pre-referral guidelines.  Accessed 29 July 2023: Primary Care Liaison : Developmental problems (rch.org.au)


Pennell, A., Couturier, J., Grant, C., Johnson, N. (2016) Severe Avoidant / Restrictive Food Intake Disorder and Coexisting Stimulant Treated Attention Hyperactivity Disorder.  International Journal of Eating Disorders.  49(11), 1036-1039.  


Pruccoli, J., Giulia, G., La Tempa, A., Valeriani, B., Chiavarino, F., Parmeggiani, A. (2023) Food and Development: Children and Adolescents with Neurodevelopmental and Comorbid Eating Disorders—A Case Series. Journal of Behavioual Sciences. 2023, 13, 499. https://doi.org/10.3390/bs13060499 



Villa, F., et. al. (2021) ADHD and eating disorders in childhood and adolescence: An updated minireview.  Journal of Affective Disorders, 321, 265-271. https://doi.org/10.1016/j.jad.2022.10.016

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