Nervous System Dysregulation – ASD vs ADHD

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Sad boy sick of autism. Plays with yellow toy car while his mother is looking at him royalty free stock photography

I’m not an expert on ASD and ADHD – but there seems to be a lot of misunderstanding out there around the connections and differences between these conditions, so thought I’d put forward my 2 cents.

This is just my opinion based on what I’ve read and observed. Observations on ASD courtesy of myself and my son, and those on ADHD based on my (possibly undiagnosed ADHD) daughter and her (definitely ADHD) boyfriend.

So one connection between these conditions is they both involve nervous system dysregulation – but they differ in the details.

Let’s not get too technical. For one thing, I always get confused myself between the sympathetic and parasympathetic nervous systems. And where does autonomic nervous system fit in? Or the somatic? Better limit myself to one paragraph of explanation here.

So our nervous system is what allows our brain to find out what’s going on in the rest of our body and control how we respond. What I’ll be talking about here is the Autonomic Nervous System (ANS). “Auto” is the same root as in “automatic” and “autonomous” – it regulates involuntary processes like heart rate, blood pressure, digestion, and breathing (and yes, we can also exert control over breathing – more on this later*). Oh darn, I need another paragraph. Bear with me…

I’m going to talk about hyperarousal and hypoarousal. “Hyper” refers to an excess and “hypo” refers to a deficit (just like in diabetes, but referring to nervous system activation instead of blood sugar). This is to avoid talking too much about the 3 types of autonomic nervous system: parasympathetic (PNS), sympathetic (SNS) and enteric (ENS? – no idea). Because I figure we’re not doctors, we don’t need to know how it all works, we just need to know how it makes us feel and what it makes us do, right? Oh dear, I need one more paragraph. Or maybe two. But this will be the last technical bit, I promise.

To quote wikipedia:  the sympathetic nervous system is often considered the “fight or flight” system… it is a “quick response mobilizing system”. So when I’m talking about hyperarousal, that generally means the SNS is activated. (See why I’m confused? Why would a system that causes me so much trouble be called “sympathetic”, instead of “uncaring”, or even “downright nasty”?)

Wikipedia again: The parasympathetic nervous system is often considered the “rest and digest” or “feed and breed” system… it is  is a “more slowly activated  dampening system”. So the PNS brings us down from “OMG I nearly crashed the car!” to “let’s vegetate in front of the TV with a bag of crisps”. Hypoarousal would be when the the body stays in this resting state instead of upping its game when needed.

(P.S. “crisps” is “chips” to you Aussies. No, Brits, we don’t mean your kind of chips – those are “hot chips” here. Or “chippies”, which also refers to carpenters, just to make things absolutely clear. So I don’t mean hot chips, otherwise known as french fries, which are actually pommes frites, I mean chips which are cold and come in bags – and just because y’all call them chips doesn’t mean they’re not crisps to me. Glad we got that sorted. Don’t get me started on how to pronounce “yoghurt”.)

So if you’re still here, it seems like the dysregulation in ADHD is easy to understand. Basically, ADHDers spend most of the time in a state of nervous system hypoarousal. So don’t expect the best from them doing a mundane desk job or something repetitive, as they’re going to be hopping from one task to another, or else hopping from one foot to the other, trying to activate their SNS enough to maintain their attention. They probably won’t finish the task but it’s not their fault – it’s the way their brain is wired.

From my observations, it seems like ADHDers can up their attention levels and achieve good performance with a combination of:

  • stimulant drugs or caffeine. These may have a reverse, calming effect on behaviour
  • doing tasks with an active, physical component
  • doing tasks with a stimulating, social component
  • working when motivated by the stress of an approaching deadline, or
  • when intensely interested in the activity

I’ve also found that they crave sugary drinks and snacks – to their detriment, as the sugar rush they need will be followed by a whopping crash. (But try telling teenagers that).

Dysregulation in ASD seems to be a little more complex. I think we can exhibit hypoarousal similar to in ADHD, which is why there can be misdiagnosis, or confusion over whether a dual diagnosis would be applicable. But the difference is that we will also suffer hyperarousal under conditions that stimulate the nervous system. That’s why autistics are prone to meltdowns or shutdowns under conditions of stress or overwhelm. (This is not just my opinion – there’ve been scientific studies showing ANS dysfunction in autistics based on measurement of heart rate and the stress hormone cortisol).

As a personal example, my reaction to caffeine varies depending on the state of my nervous system. Typically I can handle a modest amount of coffee and it usually helps with concentration, but if I am in a hyperaroused state the caffeine will boost the SNS further and make things decidedly uncomfortable.

Autistics generally use repetitive body movements to help regulate our nervous systems. I don’t like the term “stims” (short for “self-stimulatory behaviours”) because it’s a misnomer – the movements may be used either to stimulate or to soothe; they are “regulatory behaviours” (“regs”? “lates”?). For instance, when I’m getting overwhelmed at work I will get up and walk around – but I might also get up and walk around to stimulate myself when I’m feeling bored. I play with my fingers when I’m nervous but might also do so when I’m trying to concentrate. I may not even know whether I’m hypo- or hyper-aroused, I just know that I don’t feel comfortable sitting still at that moment.

You can see that the nature of nervous system dysregulation in ASD means we have different (and often opposite) requirements to ADHDers to achieve good outcomes:

  • avoiding stimulants and caffeine, especially when stressed, angry or upset
  • doing tasks with an active, physical component – for short periods with calming rest breaks in between
  • avoiding or limiting tasks with a stimulating, social component
  • working without the stress of an approaching deadline

The only common factor to achievement within both groups is:

  • being intensely interested in the activity

In other words, whatever your neurotype, do what you enjoy!

*A final word, as promised, on the matter of respiration. Breathing is one of the few processes controlled by the ANS over which we can also exert conscious control. This works both ways – meaning we can use breath control to influence the state of our nervous system. Think of it as respiratory “stimming” (“regging”? “lating”? Hm, I need a better term). That’s why breathing is such an important part of practices such as meditation and yoga – and recommended for anyone who suffers any kind of hyperarousal such as anxiety or panic attacks or PTSD, as well as autism.

That’s all for now; hope this post provided a bit of intellectual stimulation (without triggering too much pacing!)

2 thoughts on “Nervous System Dysregulation – ASD vs ADHD”

  1. You have a very good grasp on the technicalities. Knowing these things doesn’t mean they are handled as such. I was wondering how does this translate into daily life. For instance what should happen in a household you discuss in order for the people concerned to grow and comfortably live their lives. Let’s face facts. We all need to be equipped to earn a living and to live within a community.
    Having taught a classroom of mixed “diagnosis” I had to have strategies in place in order to give the students the best possible chance to not only succeed but to interpret the strategy and modify it in other situations outside the classroom. On a daily basis what would work for you? What are your suggestions for a household and can you share as I firmly believe it would benefit others. We too often don’t know how to help if we don’t know.

    Liked by 1 person

    1. That’s a good question. To be honest, in my household we just sort of muddle along. Certainly there are times when the needs of the autistics clash with the needs of the ADHDers and vice versa. The main thing is to try to be patient and understanding of each others’ needs and difficulties.
      Some strategies for my situation have been: helping my ASD son with expressing his needs, and reassuring him that he has a right to be heard and understood. He’s now getting help with work skills through one-on-one coaching funded by the NDIS. For my daughter, it’s more about teaching her patience, and helping her with academic and organisational skills. School wasn’t working for her because of dyslexia and other issues, so she’s been doing certificate courses under the government-funded “Get set for work” program, and is getting work experience through that. So one thing I would say is that government-funded programs to help school leavers with disabilities and/or mental health issues have been a godsend for us.
      But everyone is different, I’m sure other people have different needs and strategies. The main thing is to actually ask people what their difficulties are and what they need rather than making assumptions.


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