ADHD underdiagnosis in New Zealand revealed in landmark study
Byron Rangiwai has been called bright for as long as he can remember.
His school reports said so, in almost exactly those words: “Byron is a bright child but needs to focus”. His teachers could see his intelligence, but they couldn’t see that his struggles were more than his behaviour and choices.
He wasn’t choosing anything. He was masking, often by being a class clown, unable to achieve, and slowly internalising the belief that something was fundamentally wrong with him.
Rangiwai (Ngāti Manawa, Ngāti Whare, Ngāti Porou, Ngāi Tūhoe) is now an associate professor of Māori and Indigenous Research at Unitec (Te Whare Wānanga o Wairaka) and holds two PhDs. He was diagnosed with ADHD at 43.
It was only after his diagnosis that he understood what drove him to complete both degrees.
“Before my diagnosis, I’d say I did two PhDs because it was fun,” he says.
“After my diagnosis, I know it was because I still didn’t feel good enough. I knew when I did the second degree, and I still didn’t feel enough, that nothing I achieved was ever going to give me that.”
For many adults who receive a late ADHD diagnosis, this is a familiar feeling. While the labels accumulate, so does the self-doubt and the belief that you are simply not quite right.
“People who are diagnosed when they’re older seem to mourn,” Rangiwai says.
“They go through a grieving of things that could have been. I’m over that now. But I really felt a deep sense of lost potential.”
According to a new, landmark report, stories like his continue to play out across Aotearoa.
A fresh picture of neurodevelopmental conditions in Aotearoa, The Kanorau ā-roro Report, meaning “the many faces of the mind”, was released this year by the New Zealand Child and Youth Epidemiology Service (NZCYES) based at the University of Otago.
Previous data on neurodevelopmental conditions in New Zealand have come in regional pieces; this report is the first nationally linked picture, drawing on health, disability, pharmaceutical and mental health datasets from across the motu.
It covers ADHD, autism, intellectual disability, Fetal Alcohol Spectrum Disorder (FASD) and other disorders in children and young people up to the age of 24.
The report shows that internationally, around 8% of children and adolescents meet criteria for ADHD. In New Zealand, the rate sits between 2% and 4%.
Researchers say this is not because fewer New Zealand children have ADHD, but because the data only captures children who have reached services and received a diagnosis. The report is explicit: this is likely a substantial undercount of the true numbers.
“This report is a landmark first step in identifying prevalence within the health system, but we know these figures are just the tip of the iceberg,” says Sonja Crone, president of the Paediatric Society of New Zealand Te Kāhui Mātai Arotamariki o Aotearoa (PSNZ), who commissioned the report with Health New Zealand.
“Further research is vital to ensure we can direct the right support to every child, allowing them the opportunity to flourish.”
The report also found that for tamariki Māori and Pacific children, the greater the socioeconomic disadvantage, the less likely a child is to be identified as having ADHD, reflecting unequal access to diagnosis and support, layered onto communities already carrying the weight of systemic underinvestment.
“Missed identification can often leave children asking ‘What is wrong with me?’ rather than ‘How does my brain work?” Crone says.
“That distinction is where we see the most significant clinical impact on self-esteem and long-term mental health. In an Aotearoa context, ensuring equitable access to diagnosis means acknowledging that many tamariki are currently being overlooked. If we want every child to reach their full potential, we have to remove the systemic hurdles that make support a privilege rather than a right.”
Unidentified and unsupported ADHD can be a risk factor for poor mental health, school disengagement, difficulty in employment and relationships, and increased involvement with the justice system.
Global estimates put the rate of ADHD at anywhere between 25% to 55% in the adult prison population and 30% to 66% in the youth justice population.
For Rangiwai, the cost of not knowing he had ADHD was decades of feeling like he was struggling.
He left high school with only a school qualification in English, a marginal pass in the one subject he could write his way through. Everything else, he failed. He eventually went to university as a mature student, and continued to struggle. At one point, he walked into an exam, wrote down his name, waited out the clock and left. He accumulated debt. He started and abandoned courses.
“My dream was to be a lawyer,” he says. “I know now that being a lawyer shouldn’t have been out of my reach; I could excel at that job, but I just couldn’t get through the study. With the right support, I know that could have been a possibility for me; that’s the worst thing about it.”
He eventually found his academic voice at Te Whare Wānanga o Awanuiarangi in Whakatāne where, for the first time, he says he was in a learning environment shaped by Kaupapa Māori values.
“If someone had said at primary school, ‘this kid’s got ADHD, let’s get the treatments, the pedagogy, the scaffolding all around him’, maybe I’d be a lawyer right now. It would have made all the difference.”
Rangiwai is part of a wave of adults across the world seeking and receiving ADHD diagnoses. Many are finding, often for the first time, the language for things they have experienced their whole lives and the realisation that everyone’s brain doesn’t operate like theirs.
Rangiwai’s academic work has focused on developing Māori frameworks for understanding ADHD, to exist alongside clinical knowledge, including the Pīwakawaka Framework, which draws on the behaviour of the fantail as a culturally grounded way of understanding ADHD.
Where clinical language sees deficit, the pīwakawaka offers a different lens: a bird known for its quick movement, curiosity and ability to change direction mid-flight. Qualities that in a Māori worldview are not symptoms to be managed but traits to be understood and valued.
“Western deficit models define ADHD only as a disorder,” Rangiwai says.
“Māori need frameworks that reframe neurodivergence as strength, not weakness. Undiagnosed, untreated, unsupported ADHD is having serious consequences for our people. But the diagnosis itself also needs to be decolonised.”
The Kanorau ā-roro report does not identify failings in any single part of the system. The pathways through which children are identified or not identified as having ADHD run through primary care, schools, early childhood services, community organisations, whānau and specialist services.
“It has to be an all-systems approach,” Rangiwai says.
“If you think about some scholars estimating 20% of the population as neurodivergent, that’s a lot of people who could be doing things differently, or just struggling unnecessarily, in every part of life: education, justice, employment, and health. The justice system and ADHD rates in prison perfectly illustrate what early intervention could prevent.”
Rangiwai thinks back to his early years and remembers the clever, struggling kid in Murupara who couldn’t sit still, couldn’t concentrate, and was still being hit across the knuckles with a wooden ruler for it. He thinks of that child with compassion.
“[If I could talk to him now] I’d tell him he’s enough. Right now, as he is, he’s enough.”
Ruth Dryfhout works for the Paediatric Society of New Zealand | Te Kāhui Mātai Arotamariki o Aotearoa