A new University of Otago study reveals a threefold increase in autism spectrum disorder diagnoses in New Zealand since 2009, highlighting pressure on healthcare services and significant rises among Māori and adults.
A University of Otago study has found that autism spectrum disorder diagnoses in New Zealand have more than tripled in 15 years, a rise the researchers say will put continuing pressure on health and disability services. Published in the Australian and New Zealand Journal of Psychiatry, the analysis is the first to track diagnosis trends across both children and adults using three national health and disability databases from 2009 to 2023.
The study identified more than 30,800 people with an autism diagnosis during that period. By 2023, 1.3% of New Zealand children and 0.14% of adults had a recorded diagnosis, with increases seen across all age groups, genders and ethnicities. Associate Professor Ben Beaglehole, who led the work, said the pattern mirrored international trends and did not appear to be slowing.
The researchers said there was unlikely to be a single explanation for the increase. Greater awareness, broader diagnostic criteria, improved access to assessment and changes in health care practice were all likely contributors. Beaglehole also said broader environmental and social influences could not be ruled out, while the team concluded the trend was unlikely to be explained by genetics alone. The study also found that more pre-school children were being diagnosed, suggesting earlier recognition.
Beaglehole said the growth in adult diagnoses was especially significant because autism has often been treated as a childhood condition. He argued that adult services now need more expertise and capacity, while child and family services will also need better workforce planning. The study found autism remained more common among males, but diagnoses in females rose faster over the 15-year period.
The most striking shift was among Māori. Diagnosis rates, which were lower than those for non-Māori in 2009, rose almost fivefold and had overtaken non-Māori by 2023. Separately, the University of Otago says its Quantitative Social Science Research Group is running a wider study of autism prevalence and health service use among autistic young people in Aotearoa, with a focus on ethnic disparities and the needs of gender-diverse populations.
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