Yesterday I lost eleven minutes to the question of whether my photography books should be arranged by height or by photographer. Not idly. With the focused intensity of a man defusing a bomb, or possibly building one. It mattered, in a way I could not have justified to another living soul, and the mattering had me by the collar. Then my phone buzzed, and some older, hungrier part of me abandoned the whole cathedral of the project to go and see what the buzz wanted.
It wanted nothing. A software update. The digital equivalent of a stranger tapping you on the shoulder to tell you they have nothing to say.
So there I stood, holding a Salgado I no longer had a plan for, in the smoking ruins of my own attention, furious out of all proportion and grieving a small ordered world I’d been about three minutes from finishing. That last feeling is the one that matters. Not the anger. The grief. The specific, disproportionate mourning for a tidy shelf that never got to exist.
Because that was one thing happening to one man, not two. And most of the good, kind, popular writing about the autistic-and-ADHD brain walks straight past it.
What Lindsey gets right
I want to start with someone worth reading. Lindsey Mackereth writes a Substack called Complexity Edge, she has a large and devoted following, and she recently published a piece called ‘AuDHD Isn’t Autism + ADHD. It’s a Third Experience.’ If you have AuDHD, or you love someone who does, go and read it. I mean that plainly, before I disagree with a word of it.
She gets the big thing right, and the big thing is the one most people miss. She refuses the arithmetic. The lazy version of AuDHD treats it as simple addition: autism traits in one column, ADHD traits in the other, tot them up and hand the person the bill. Lindsey says no, the combination is more than the sum, a synergy rather than a stack. She is right, and that single instinct is worth more than most of what gets written on the subject.
She also manages the thing good clinical writing is supposed to do and rarely does, which is make the reader feel seen. Her catalogue of the lived collisions is vivid and accurate: the lurch between social withdrawal and blurting; the war between a craving for routine and an itch for novelty; the attention that hyperfocuses like a laser and then shatters at a passing shadow; the sensory afternoons that end in tears; the reward system that works on Monday and has quietly resigned by Thursday; the executive function that turns tidying one room into an unsolvable maze; the nights spent interrogating the ceiling. Anyone living inside an AuDHD nervous system will read that list and exhale, because someone has finally described the weather they live in.
That is real work, and I do not want a word of what follows to sound like knocking it down.
Where I part company, gently
Here is where I keep tugging at the thread, though. Lindsey names seven collisions. Seven is a lot of collisions. And I wonder whether naming seven separate phenomena, however well, leaves the reader holding a weather report when what they need is to know about the front that is producing all the weather. Describe the storms one at a time and each of them is real. Miss the pressure system underneath and you walk away convinced you have seven problems, when you might have one, wearing seven coats.
I also wonder whether some of the seven are collisions at all. A collision needs two things hitting each other. The social lurch qualifies: autistic caution smacking into ADHD impulse. The routine-versus-novelty war is the collision in its purest form. But the sensory overload, the executive collapse, the sleepless nights? Those do not feel to me like autism and ADHD striking each other. They feel like exhaust, the stuff that comes out the back of an engine that has been running too hard, for reasons we are about to get to.
So there is another way to think about this. Not opposed to Lindsey’s. Underneath it.
The two governors
Start with the engine, because everything else is downstream of it.
Autism, on one of the more persuasive accounts, runs attention as a single deep channel. The idea is called monotropism: a mind that pours most of its available processing onto a few things at a time, intensely, and guards that tunnel against interruption with what looks from the outside like sheer bloody-mindedness (Murray, Lesser, & Lawson, 2005). The set-point of the whole system tilts toward depth, sameness, immersion, and staying exactly where it is. Change the plan and something in me genuinely grieves. Not sulks. Grieves. A small bereavement, every time, because a thing I was inside has ended.
ADHD is built facing the other way. One of the sturdier accounts, the dual-pathway model, describes a good part of ADHD as a motivational style organised around escaping delay: a reward system that will do almost anything rather than sit in the flat grey waiting room of the present, and that lunges at whatever is new, bright, loud, and available right now (Sonuga-Barke, 2003). Its set-point tilts toward switching, novelty, speed, and motion. It does not want the tunnel. It wants the next tunnel, and the one after that, ideally both at once.
Now bolt both of those into one nervous system and ask it to get through a Tuesday. One foot flat on the accelerator, the other stamping the brake, and a bewildered passenger in the back seat wondering aloud why the whole car smells of burning. The passenger is you. So is the accelerator. So is the brake. There is nobody else in the vehicle, which is precisely the problem.
The symptoms talk to each other
If AuDHD were honest addition, the two columns would ignore one another, two tenants in one building who never meet on the stairs. They do not behave that way. When a team actually modelled how the traits relate, they did not find two tidy separate lists. They found wiring running between them: impulsivity feeding into trouble reading social situations, hyperactivity feeding into repetitive behaviour, the two conditions plumbed into one another rather than merely sharing an address (Sokolova et al., 2017). The review literature reaches the same place by a different road. Autism and ADHD overlap heavily in how they present, and the combined version is still distinct enough to be its own creature, not a photocopy of either parent (Antshel & Russo, 2019).
It is worth remembering how young this understanding is, and why. Until embarrassingly recently the arithmetic was official. The DSM-IV forbade diagnosing both at once. Autism was an explicit exclusion for ADHD, so the single most common presentation a clinician might actually see was ruled out of existence by the manual on the desk (Leitner, 2014). The DSM-5 lifted the ban in 2013. I am 67. I will let you do the melancholy sum on how long a person can be handed one half of himself while the reference book insists the other half is not permitted to be there. That is not a neutral clerical error. It is the reason a generation of us grew up being called lazy, or difficult, or gifted-but-not-applying-ourselves, according to taste.
So the collapse at my bookshelf was the two governors working together, producing a third thing that neither makes alone: a mind that can want depth and flight in the same breath and be genuinely unable to choose. Nobody running a single neurotype gets that particular weather. Lindsey is right about the third experience. I simply think the third experience has a mechanism, the mechanism has a cost, and the cost is where this stops being interesting and starts being useful.
The bill for running two engines
The part I think the seven-collisions map leaves out is the one that changes what you do on Monday morning. Running two opposed governors all day is not free. It costs something, and the currency is physiological.
Your body is built to handle stress in bursts. Something threatens you, a beautifully engineered system floods you with cortisol and adrenaline, carries you through the moment, then powers down and repairs the damage. Bruce McEwen and Eliot Stellar gave this flexing a name in 1993. The flex itself is allostasis, and it is a marvel of design (McEwen & Stellar, 1993). The trouble is never the single flex. The trouble is the bill for flexing too often, which they called allostatic load: the accumulated wear and tear on a body whose alarm keeps getting switched on with too little quiet in between to reset and repair (McEwen & Stellar, 1993).
And here is the mechanism that matters for us. One of the main ways that load builds, McEwen showed, is the simplest one imaginable: repeated hits, new stressors arriving before the body has recovered from the last (McEwen, 1998). It does not take a monster. It takes a queue. Small thing, small thing, small thing, none of them a catastrophe, each one landing before the one before it has cleared.
Now look again at the two governors. The neurotypical nervous system mostly meets that queue from the outside: the traffic, the deadlines, the difficult emails, the ordinary friction of a day. The AuDHD nervous system meets all of that too, and then, on top of it, runs its own private stressor generator inside the skull, all day, for free. The tunnel wants to stay, the reward system wants to bolt, and the friction between them is a genuine physiological load, not a figure of speech. Every hijacked task, every grieved interruption, every lurch between burrowing and fleeing is one more small hit on a system that never gets its quiet back, because the thing generating the hits is you, and you turn up every day.
When the flexing finally outruns the body’s capacity to keep adapting, you reach what McEwen’s colleagues later named allostatic overload, the point where adaptation itself tips into breakdown (Juster, McEwen, & Lupien, 2010). Which puts Lindsey’s back three collisions in a rather different light. The sensory overload, the executive collapse, the sleepless 2am ceiling: I think we are looking at what allostatic overload does from the inside, rather than at two more fights between autism and ADHD. Not seven collisions. Two collisions and a body presenting the invoice for having refereed them since breakfast.
The word for where this ends
There is a name for where this lands in an autistic life, and it is one of the more important ideas to come out of autistic-led research in the past decade. Studying autistic adults directly, Dora Raymaker and colleagues defined autistic burnout as arising from ‘chronic life stress and a mismatch of expectations and abilities without adequate support’ (Raymaker et al., 2020, p. 133): pervasive exhaustion, a loss of previously reliable skills, and a tolerance for any further input that has simply run out.
Read that definition again with the engine in mind. Chronic stress, no recovery, expectations that keep outrunning a depleted system. That is allostatic overload wearing autism’s clothes. And the AuDHD version runs the deficit faster than either condition alone, because there are two motors draining the same tank. Add masking on top, the daily performance of looking regulated and neurotypical while the referee inside is quietly losing, and you have a system paying a tax it never agreed to, in a currency it is running out of. This is the point in the essay where I should tell you I have never once done this to myself. I have done this to myself for most of my adult life.
None of it is weakness, and none of it is a character flaw, whatever your school report implied. It is the predictable, measurable output of an architecture built with two engines that pull against each other and a body that keeps every receipt.
What actually helps
Which finally changes what help looks like, and here the standard advice does the most damage. You do not fix a two-engine problem with a better morning routine. You certainly do not fix it by trying harder, the counsel reliably dispensed to neurodivergent people by everyone who has never spent an afternoon inside the machine. Willpower is not the missing ingredient. Asking an AuDHD nervous system to try harder is asking a car with one foot on each pedal to solve the problem by pressing both pedals with more conviction.
The set-points are not broken. They do not need sanding down into some obedient neurotypical average. What they need, and what the allostatic frame actually prescribes, is recovery. A body carrying allostatic load does not heal by toughening up. It heals by getting its quiet back, the intervals of real rest the alarm system needs in order to power down and repair (Juster, McEwen, & Lupien, 2010). For a nervous system like mine that has meant treating the environment as medicine rather than decoration. Fewer channels clamouring at the tunnel. Fewer forced switches. A day arranged so the two governors are not both redlined by lunchtime, and the stress system gets the gaps it needs to actually reset.
That is not a cure, and I would not sell it as one. It is load reduction: the unglamorous, badly underrated difference between a nervous system that gets to repair overnight and one that never quite does.
I would love to end this tidily, engine balanced, driver serene, invoice paid in full. I cannot, because as I write this my own tank is low and the city outside the window is doing its considerable best to finish the job it started this morning. What I have instead is smaller and truer than a neat ending. Lindsey drew the map of the storms, and it is a good map, and you should read it. I have simply come to think there is one weather system underneath all seven of them, and it sends a bill. When I read that bill as physiology rather than as personal failure, I stop stacking shame on top of the exhaustion, and shame is the one line item on the invoice I actually get to refuse. The two drivers are still in there. Still pulling. I have just stopped blaming the car, and started paying attention to the road, the quiet, and how much of each I am getting.
References
Antshel, K. M., & Russo, N. (2019). Autism spectrum disorders and ADHD: Overlapping phenomenology, diagnostic issues, and treatment considerations. Current Psychiatry Reports, 21(5), 34. https://doi.org/10.1007/s11920-019-1020-5
Juster, R.-P., McEwen, B. S., & Lupien, S. J. (2010). Allostatic load biomarkers of chronic stress and impact on health and cognition. Neuroscience & Biobehavioral Reviews, 35(1), 2–16. https://doi.org/10.1016/j.neubiorev.2009.10.002
Leitner, Y. (2014). The co-occurrence of autism and attention deficit hyperactivity disorder in children – what do we know? Frontiers in Human Neuroscience, 8, 268. https://doi.org/10.3389/fnhum.2014.00268
McEwen, B. S. (1998). Protective and damaging effects of stress mediators. New England Journal of Medicine, 338(3), 171–179. https://doi.org/10.1056/NEJM199801153380307
McEwen, B. S., & Stellar, E. (1993). Stress and the individual: Mechanisms leading to disease. Archives of Internal Medicine, 153(18), 2093–2101. https://doi.org/10.1001/archinte.1993.00410180039004
Murray, D., Lesser, M., & Lawson, W. (2005). Attention, monotropism and the diagnostic criteria for autism. Autism, 9(2), 139–156. https://doi.org/10.1177/1362361305051398
Raymaker, D. M., Teo, A. R., Steckler, N. A., Lentz, B., Scharer, M., Delos Santos, A., Kapp, S. K., Hunter, M., Joyce, A., & Nicolaidis, C. (2020). “Having all of your internal resources exhausted beyond measure and being left with no clean-up crew”: Defining autistic burnout. Autism in Adulthood, 2(2), 132–143. https://doi.org/10.1089/aut.2019.0079
Sokolova, E., Oerlemans, A. M., Rommelse, N. N., Groot, P., Hartman, C. A., Glennon, J. C., Claassen, T., Heskes, T., & Buitelaar, J. K. (2017). A causal and mediation analysis of the comorbidity between attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD). Journal of Autism and Developmental Disorders, 47(6), 1595–1604. https://doi.org/10.1007/s10803-017-3083-7
Sonuga-Barke, E. J. S. (2003). The dual pathway model of AD/HD: An elaboration of neuro-developmental characteristics. Neuroscience & Biobehavioral Reviews, 27(7), 593–604. https://doi.org/10.1016/j.neubiorev.2003.08.005
Further reading
Mackereth, L. (2026). ‘AuDHD Isn’t Autism + ADHD. It’s a Third Experience.’ Complexity Edge (Substack). https://lindseymackereth.substack.com/p/audhd-isnt-autism-adhd-its-a-third
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