Autism and ADHD: More Connected Than You Might Think

If you've recently received a diagnosis — or are in the process of exploring one — and find yourself wondering whether what you're experiencing is autism, ADHD, or both, you're asking exactly the right question. And the honest answer is: it's often both, and that's not a coincidence.

A brief overview

Autism is characterized by differences in social interaction and communication, and a tendency to self-regulate through repetition, routine, and predictability. ADHD is characterized by differences in attention regulation and impulse control. For a long time, these two were treated as mutually exclusive: if you had one, you couldn't be diagnosed with the other. Thankfully, that changed with the DSM-5, which now allows both diagnoses to co-exist. But the reality is that the overlap between them is so significant that many researchers believe they share a common genetic origin.

The numbers are striking: between 22% and 83% of autistic children meet the criteria for ADHD, and between 30% and 65% of children with ADHD have significant autistic traits (Sokolova et al., 2017). Studies of twins consistently show a 50-72% overlap in contributing genetic factors. These aren't small numbers. They're telling us something fundamental about how these neurotypes relate to each other.

As Neurodivergent Insights puts it, "pure autism" or "pure ADHD" may be the exception rather than the norm, and from everything I've seen, I think that's right. Through years of supporting autistic and neurodivergent people, both in the Latin American community and, more recently, in classrooms here in Canada, I've seen again and again that trying to fit a neurodivergent person into a single diagnosis rarely holds up when it comes to building support that actually works. Most of the people I meet live somewhere in the overlap, carrying traits from both to varying degrees, whether or not they meet the full criteria for each diagnosis. And that matters: if you've been diagnosed with one and feel like something still isn't being captured, you may well be right.

When two neurotypes share one nervous system

I see this up close in my own life. My partner is both autistic and has ADHD, and watching him navigate the world has given me a window into something that is genuinely hard to put into words, but I'll try.

The autistic nervous system tends to find safety in predictability. Routine, structure, and knowing what comes next aren't preferences, they're regulatory tools. The ADHD nervous system regulates in the opposite direction: it's drawn toward novelty, movement, and stimulation, and can disengage quickly from what feels repetitive, not from carelessness, but because under-stimulation is its own kind of dysregulation. That pull toward the new isn't restlessness or a lack of discipline; it's how an interest-based nervous system activates and engages. Where the autistic system reaches for the familiar to steady itself, the ADHD system reaches for the new. When these two neurotypes coexist in the same person, they can pull in opposite directions in ways that are exhausting and deeply confusing from the inside.

That inner tension between the part that needs everything to stay the same and the part that needs everything to be new can look a lot like depression, low motivation, or emotional dysregulation from the outside. And it often gets misread as exactly that. Research confirms that people with both autism and ADHD are at significantly increased risk of being diagnosed with depression and anxiety, a vulnerability that frequently stems not from autism or ADHD themselves, but from living in a world that doesn't understand or accommodate them (Capp et al., 2025). Executive functioning, in particular, can become a real site of struggle: not because the person lacks intelligence or drive, but because the two systems are working against each other in the same brain.

What makes this even more complex is that people who are both autistic and ADHD often wait the longest to receive an accurate diagnosis because the autism masks some of the ADHD, and the ADHD changes how the autism presents (Langan & Cira, as cited in Wright, 2026). Each neurotype obscures the other, making the full picture harder to see.

This misunderstanding carries a real cost, and it falls disproportionately on women. Many spend years on a diagnostic journey, treated for depression or anxiety, accumulating strategies and medications that never quite work, before discovering that the origin lay in their neurodivergence. A study from the Netherlands with over 1,200 autistic adults found that one in three autistic women reported having received at least one prior psychiatric diagnosis they felt didn't fit, most often personality, anxiety, and mood disorders (Kentrou et al., 2024). The pattern repeats with ADHD: women are roughly twice as likely as men to have received a depression or anxiety diagnosis in the year before their ADHD is finally recognized (Siddiqui et al., 2024). And when both neurotypes coexist, the confusion deepens: research with AuDHD women describes living undiagnosed as a confusing and exhausting experience, often marked by years of treatment focused on their anxiety or mood rather than their neurology (Wills & Chakraborty, 2026). 

What it actually feels like

My brother was recently diagnosed with ADHD. When he tried to explain what it was like from the inside, he described it as having different mini versions of himself in his head, all competing to take control of his attention, and through that, his actions. Since his diagnosis, and with the support of medication and therapy, he says he feels like he has more agency. Like he can choose which "mini him" gets to hold the attention rather than being pulled wherever the loudest one goes.

I found that description remarkable. Not just as a metaphor, but as a window into something that neuroscience is still working to fully understand, the experience of an attention system that doesn't filter and prioritize the way neurotypical brains do, and what it costs a person to live inside that every day.

What this means in practice

If you are autistic and have ever wondered why the strategies that are supposed to help you — routines, structure, clear expectations — sometimes feel simultaneously essential and suffocating, the ADHD piece may be part of that picture. If you have ADHD and have ever felt like your sensory experience, your social exhaustion, or your need for predictability doesn't quite fit the ADHD narrative alone, it may be worth exploring whether autism is also part of your story.

These are not two separate things happening at the same time. They are two expressions of a neurodivergent nervous system that are deeply intertwined genetically, neurobiologically, and in lived experience. Understanding both, together, is the only way to build support that actually fits.

References

• Capp, S., De Burca, A., Aydin, Ü., Agnew-Blais, J., Lautarescu, A., Ronald, A., Happé, F., & McLoughlin, G. (2025). Depression and anxiety are increased in autism and ADHD: Evidence from a young adult community-based sample. JCPP Advances, e70003. https://doi.org/10.1002/jcv2.70003 
• Kentrou, V., Livingston, L. A., Grove, R., Hoekstra, R. A., & Begeer, S. (2024). Perceived misdiagnosis of psychiatric conditions in autistic adults. eClinicalMedicine, 71, 102586. https://doi.org/10.1016/j.eclinm.2024.102586
• Siddiqui, U., Conover, M. M., Voss, E. A., Kern, D. M., Litvak, M., & Antunes, J. (2024). Sex differences in diagnosis and treatment timing of comorbid depression/anxiety and disease subtypes in patients with ADHD: A database study. Journal of Attention Disorders, 28(10), 1347–1356. https://doi.org/10.1177/10870547241251738
• Sokolova, E., et al. (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
• Wills, V., & Chakraborty, R. (2026). A qualitative study on the experiences of adult females with late diagnosis of ASD and ADHD in the UK. Healthcare, 14(2), 209. https://doi.org/10.3390/healthcare14020209
• Wright, K. (2026, March 18). Scientists are starting to understand how autism and ADHD can overlap. National Geographic. https://www.nationalgeographic.com/health/article/what-is-audhd-adhd-autism-overlap-adults

This post also draws on the original article by Neurodivergent Insights: ADHD vs Autism

 

Image: Neurodivergent Insights

*I use identity-first language for autism and person-first for ADHD, following each community's prevailing preference