Why ADHD, Dyslexia, and Dyscalculia Love to Hang Out Together (and What It Means for Families)

Tuesday, March 25, 2025.

As a family therapist, I’ve seen the same question echo through the minds of exhausted parents and overwhelmed kids: Why does my child struggle with everything at once?

When one diagnosis pops up—ADHD, for example—others often follow, like a conga line of learning challenges: dyslexia, dyscalculia, executive function disorder, anxiety. Is it just bad luck?

A landmark study out of the Netherlands offers a compelling (and slightly comforting) answer: it’s in the genes.

The Hidden Family Resemblance Among Learning Differences

In a study involving over 19,000 Dutch twins, researchers confirmed what many clinicians and parents have long suspected: ADHD, dyslexia, and dyscalculia often occur together because they share the same genetic underpinnings.

That’s right.

These learning differences aren’t ganging up on your child out of spite or poor parenting.

They’re genetically linked. Like cousins who show up uninvited to the same holiday party, ADHD, dyslexia, and dyscalculia tend to cluster together, not because one causes the other, but because they’re wired to cohabitate.

Published in Psychological Science, the study demonstrates that shared genes explain much of the overlap—not poor classroom behavior, screen time, or even (gasp) parenting.

That doesn’t mean the environment doesn’t matter. It absolutely does. But the genetic architecture lays the groundwork.

Decoding the Triple Threat: What Are We Talking About?

Let’s briefly define our cast of characters:

• ADHD affects attention, impulse control, and hyperactivity. Think: mental popcorn machine.

• Dyslexia interferes with reading and spelling. Think: letters doing the Macarena.

• Dyscalculia disrupts understanding of numbers and math. Think: math class as an alien language.

The study found that if a child has ADHD, they’re 2.7 times more likely to have dyslexia and 2.1 times more likely to have dyscalculia. That’s more than coincidence—it’s a shared vulnerability.

One Diagnosis Does Not Explain It All

Many families assume causation when they see co-occurring conditions. For example, “My child can’t sit still, so of course he struggles to read.” Or, “She hates math because she’s impulsive and skips steps.”

But this study throws a wrench into those assumptions.

The research team—led by Dr. Elsje van Bergen at Vrije Universiteit Amsterdam—used twin data to untangle cause from correlation. Their analysis showed that it’s not one condition causing the other, but rather a shared set of genetic risk factors fueling all three.

In plain English: your child didn’t get ADHD and then flunk reading. They were genetically preloaded for both.

The Power (and Limits) of Heritability

The researchers estimate that around 75% of the differences in how children develop ADHD symptoms—or struggle with reading, spelling, and math—are genetically driven. That’s a big number. But it doesn’t mean these conditions are fixed, permanent, or unchangeable.

“Children learn these skills because of high-quality education,” van Bergen reminds us. Even with a genetic headwind, good teaching and early intervention can dramatically change a child’s trajectory.

And for the record, at least in this study, not every child with one condition has another. In fact, 77% of kids with ADHD, dyslexia, or dyscalculia didn’t have a detectable second or third diagnosis. So we should be cautious about assuming that the over-clustering of symptoms is always the norm, and turning kids into bundles of pathology.

Why This Matters in Real Life (Especially for Families)

Let’s step back for a moment.

If you’re the parent of a child with ADHD who’s also struggling in math and reading, this research offers more than just a genetic explanation—it provides validation and clarity. You didn’t miss something. Your child isn’t lazy. You’re not failing.

What this research does change is how we approach support.

• Don’t Expect a Magic Bullet. Treating ADHD alone might not fix reading or math challenges.

• Support each Challenge Individually. Tailored interventions for reading (like Orton-Gillingham) or math (like Number Sense tutoring) are still necessary, even if ADHD is being treated.

• Educate the Educators. Schools need to understand that comorbidity isn’t always behavioral—it’s biological.

• Know Your Family History. If learning struggles run in your family, early screening and support are gold.

What This Means for Therapists and Clinicians

As a marriage and family therapist working in both Public Health, and Private Practice, I see this research as a call to ditch the linear thinking.

Too often we treat symptoms in isolation. We try to "fix" the child’s behavior without exploring the learning environment or underlying wiring. Or we treat school failure as a side effect of distraction without screening for dyslexia or dyscalculia.

We also tend to underestimate the emotional toll these overlapping conditions create. Kids with multiple learning difficulties often internalize failure. They’re misread as careless, oppositional, or unmotivated. In truth, they’re trying harder than anyone else in the classroom—just to stay afloat.

Therapy must acknowledge both the neurobiology and the emotional landscape.

A Word About Genes, Labels, and the Human Spirit

Dr. van Bergen makes an important point: recognizing genetic influences isn’t about labeling kids. It’s about understanding what they need—so we can stop shaming them and start helping them thrive.

Genes load the gun, as the old saying goes, but environment pulls the trigger—or holsters it. The earlier we understand a child’s learning profile, the more effectively we can shape the environment to meet their needs.

That’s not destiny. That’s hope.

Final Thought: Families Are Also Wired Differently

Just as kids are neurologically diverse, so are families.

If your child is struggling, you may be too.

Many parents of kids with ADHD or dyslexia share those traits themselves—and have gone undiagnosed. So this is your reminder: getting support for your child often means getting a second look at your own learning and attention habits. If you’ve read this far, I can help with that.

In family therapy, we call that a systems perspective—recognizing that we’re all part of a larger, intertwined picture. Genes connect us. So do patience, creativity, and relentless love.

Be Well, Stay Kind, and Godspeed.

REFERENCES:

van Bergen, E., de Zeeuw, E. L., Hart, S. A., Boomsma, D. I., de Geus, E. J. C., & Kan, K.-J. (2024). Co-Occurrence and Causality Among ADHD, Dyslexia, and Dyscalculia. Psychological Science.