More autism diagnoses: what fifteen years of data from New Zealand reveal

Maybe you have noticed it in the waiting room, at school or in your own family: autism now comes up in conversations where, a few years ago, it was barely mentioned. More and more children receive a diagnosis, and so do adults who reach it after a lifetime of feeling different without knowing why. Is this a real increase, or a way of looking that has finally learned to recognize it? A New Zealand study published this year offers solid data to think about that question calmly.

What they studied

Ben Beaglehole, Gordon Lu and Chris Frampton, from the University of Otago and the country’s public health service (Health New Zealand – Te Whatu Ora), brought together three large national databases: specialist mental health services, hospital discharges and Socrates, the system that determines who can access disability support. They looked for everyone with an autism diagnosis recorded between 2009 and 2023 and, when someone appeared in more than one database, counted them only once.

So that population growth would not distort the figures, they calculated rates per 100,000 inhabitants using official Stats NZ data. They separated people under 18 from adults, compared by gender, ethnicity and neighborhood deprivation, and tracked year by year who appeared for the first time.

It helps to understand what kind of work this is: it did not examine anyone or look for causes. It counted what was written in public records, which gives it great scale and also limits, which we will see below.

What they found

In total, 30,882 people appeared with an autism diagnosis over those fifteen years. The vast majority, 81%, appeared in Socrates; 84% were under 18, and about a quarter were women or girls.

The headline figure is the pace of growth. Among children and teenagers, the rate rose from 389 per 100,000 inhabitants in 2009 to 1,312 in 2023, that is, from 0.4% to 1.3%. Among adults it rose from 39.6 to 135.3 on the same scale, reaching 0.14%. In both groups, more than threefold.

First-time records followed the same curve: they tripled between 2012 and 2023, with a pause between 2018 and 2021. The average age at diagnosis fell from 14.2 to 11.2 years, and the share of children under five grew from 23% to 28%. Even so, the number of people first diagnosed in adulthood more than doubled by the end of the period.

There were also three striking changes:

• The gender gap is narrowing. Males are still the majority, but among females the increase was fourfold (from 49.6 to 208.3 per 100,000), compared with threefold among males (from 209 to 592).
• Māori went from lower rates to higher ones. In 2009 the rate was 108 per 100,000, compared with 132 for the rest of the population; in 2023, 521 versus 376. It rose almost fivefold.
• Greater presence in neighborhoods with fewer resources. 22.2% of the people identified lived in the most deprived areas, and 17.8% in the least deprived.

Why is this happening? These data cannot tell, and the authors say so. They review the explanations found in the scientific literature: broader criteria since 2013, greater awareness among families and professionals, better-resourced services and support that is only available with a diagnosis. In Australia, according to a recent study they cite, the introduction of a national disability funding scheme raised autism prevalence by 32%. They also mention possible confusion with other conditions, such as ADHD or anxiety, and lowered thresholds. Their final hypothesis points to a mix of social and environmental factors rather than genetic change. And they recall that the evidence overwhelmingly rules out any link with vaccines.

What we still don’t know

The article itself sets out its limits:

• Many adults are missing. Only diagnoses recorded in public specialist services, hospitals and disability support were counted; primary care and private practice are left out. That is why the adult figure (0.14%) is far below the 1% estimated in England by a household survey. Many autistic adults never appear in these records.
• They do not show how much support each person needs. The databases do not include that information, so they cannot tell whether the increase is concentrated among people with fewer support needs.
• They do not explain causes. None of the sources contains information about the origins of autism, so any explanation of the growth is, for now, a hypothesis.
• They do not look at other conditions at the same time. Nor did they analyze whether, for example, the increase coincides with a drop in other diagnoses, which would change how the figures are read.

What they do make clear is that recognition of autism is growing at every age and, in New Zealand, shows no sign of leveling off. The authors call for better-prepared services, especially for adults, where experience in this field has been scarce.

What we can take home

1. A diagnosis is information, not a verdict. Whether it comes in childhood or adulthood, it helps us understand how a person perceives, feels and learns. The figures are growing largely because we have learned to look more carefully, and that allows earlier and more respectful support.
2. Observe and write down what happens at home. The study reminds us that a sound diagnosis needs several sources and a view sustained over time. Your notes on how your child communicates, plays or responds to noise will be valuable to any specialist. Date each entry and describe the specific situation.
3. Don’t wait for a label to begin. While you wait for an appointment with specialists, or even if confirmation never comes, you can support development today: predictable routines, shared playtime and short moments to practice what is still in progress. And if, reading about autism, you recognize traits in yourself or another adult in the family, this study shows it is never too late to understand yourself.

The next step: meet your child at their developmental stage with TAEO | EdTech

This study leaves a lesson we share: autism is increasingly recognized, at any age, and each person who lives it brings their own mix of strengths and challenges. That is why, at TAEO | EdTech, we do not start from a label but from what your child already does. The activities are the same with or without a diagnosis; what changes is the path, which the Skills and Competencies Profile maps out from what it observes across the eight aspects.

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At the TAEO Psychoeducational Organization, we have poured more than sixteen years of experience into TAEO | EdTech so that every family has clear activities and a human team guiding them step by step.

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