A Million Young People and a Number I Can't Stop Thinking About

I've noticed something in ADHD spaces over the years. Wander into an online ADHD group or a meetup and a striking share of the room isn't straight. Or isn't the gender they were born with. I'd half assumed that was simply who turns up to that sort of thing. The people who've already spent years working out what makes them different.

Then in August 2026 a study landed that put a number on it. Not a survey of a few hundred volunteers. Every person aged 5 to 24 in New Zealand. And the number was surprising.

What the New Zealand researchers did

A team led from the University of Otago took the 2023 New Zealand census and matched it against the country's health records. Hospital admissions. Mental health services. Disability support. Pharmacy dispensing. That gave them 1,266,456 young people and a record of who had ever been diagnosed with or treated for ADHD.

The census also asks people how they describe their gender and their sexuality. So for the first time anyone could line those two things up across an entire nation rather than a sample of it.

Overall 3.4 percent of young New Zealanders had ADHD on their records. Among transgender young people it was 9.9 percent. Among 15 to 24 year olds who described themselves as anything other than heterosexual it was 8.0 percent against 3.6 percent for their heterosexual peers. After allowing for age and ethnicity and how well off their neighbourhood was, being gay or bi or otherwise not straight went with roughly double the rate of ADHD.

So what does that mean for you? If you're LGBTQ+ and you've always suspected your brain runs on a different operating system the odds have just shifted in your favour. Roughly one in twelve rather than one in thirty. That's not a rounding error. That's a pattern.

This isn't a one-off

A single study is a single study, however big. So I did some research into the scientific literature to find out whether this had been researched elsewhere.

A 2025 survey of 72,288 first-year university students across 18 countries found that non-heterosexual and transgender students had the highest rates of most mental health conditions on the list, ADHD among them. In the United States a study of 269,947 adults using medical records rather than questionnaires found ADHD running at more than twice the rate among gender diverse adults. A smaller Canadian study of 639 undergraduates found non-heterosexual students were more than four times as likely to score in the top tenth for ADHD symptoms. Even Taiwan's national health insurance records show ADHD turning up more often among children questioning their gender.

Different countries. Different cultures. Different ways of measuring. Same direction every time. Whatever is going on here it isn't a quirk of New Zealand.

But here's the thing

There's one study in this pile that does something none of the others can, and it points somewhere unexpected.

Comparing gay teenagers with straight teenagers has a flaw. The two groups differ in loads of other ways too. Different families, different schools, different genes, different childhoods. Any of those could be the real reason for the gap and you'd never know.

Swedish researchers found a way round it. Sweden keeps records on every pair of twins born in the country, and the team followed 4,898 of them to age 18. First they did the ordinary comparison and gay and bi teenagers reported more ADHD symptoms than straight teenagers they weren't related to. So far, no surprise.

Then they went looking for pairs where one twin was gay or bi and the other was straight. That is a gift to a scientist. Two people who grew up in the same house with the same parents, went to the same schools and share a big chunk of their DNA. Nearly everything that normally muddies a comparison is held still. So they asked the question again, inside each pair. Does the gay twin have more ADHD symptoms than their own straight twin?

Barely. The gap that looked large between strangers almost completely disappeared between twins.

Think about what that means. If being gay itself pushed up ADHD symptoms, through stress or anything else, the gay twin should still have scored higher. They lived the same life apart from that one difference. They didn't. So being gay, on its own, isn't doing much.

What's left is whatever the twins share. Their genes and their home. Something in that mix seems to raise the odds of both things at once.

Here's a way to picture it. Suppose kids who own skateboards break more bones than kids who don't. You'd blame the skateboards. Then you find brothers and sisters where one has a board and one doesn't, and the skateboarder breaks bones at about the same rate as their sibling. Suddenly the board isn't the explanation. Something about those families, maybe a taste for risk the parents pass down, produces both the skateboard and the broken bones.

That's what the twins are saying. The link between sexuality and ADHD is real. But sexuality looks like the skateboard.

So why does the pattern keep showing up?

Nobody knows yet and I'd be wary of anyone who says they do. But there are a few honest candidates.

The first is stress. Growing up different in a world built for the default is exhausting. Hiding parts of yourself takes brainpower and constant low-level pressure is known to make focus and impulse control worse. On this view the ADHD symptoms are partly a tax on being a minority.

The second is simpler and a bit uncomfortable. The New Zealand study counted people who reached a service. Young LGBTQ+ people are already in front of counsellors and doctors more often than their straight peers, and once someone is properly assessed for one thing the ADHD gets spotted too. Some of this doubling may be about who gets looked at rather than who has it.

The third is what the twins are pointing at. A shared root in family and biology that shows up as both traits.

There's a wrinkle worth knowing too. The census question on sexuality relies on people being willing to answer it. In some families and some cultures that's not a small ask. Anyone who kept quiet got counted as straight. That probably makes the true gap a bit bigger than 8 percent versus 3.6 percent rather than smaller, because it waters down the heterosexual group with people who don't belong in it.

What I'd actually do with this

If you're gay or bi or trans and you recognise yourself in the ADHD descriptions you've read, stop treating that as a coincidence. Take the six-question adult ADHD self-report screener, the one clinicians use, and take the result to your doctor. Say plainly that ADHD is around twice as common in people like you and you'd like a proper assessment rather than a shrug. The New Zealand authors' whole point was that the services need to catch up with this. You can speed that along by asking.

If you already have ADHD and you've wondered why so many of your closest friends turned out to be queer, now you know it wasn't your imagination. Same wiring finds same wiring.

And if you're reading this as a parent or a partner, the takeaway is gentler. A young person who is working out their identity and also can't keep track of their keys or their homework isn't two separate problems.

The bottom line

Being LGBTQ+ goes with roughly double the rate of ADHD, in a study of over a million young people and in every other decent dataset I could find. It doesn't mean one causes the other. The twin research suggests they grow from shared roots. What it does mean is that if you're gay or bi or trans and you've suspected ADHD for years the odds say you're right to wonder. Do the six-question screener today and book the conversation with your doctor this week. The longer that assessment waits the more of your life it costs you.

Photo by Altin Ferreira on Unsplash.