NZ epidemiological study of neurodevelopmental disorders
What is the prevalence of ADHD, autism, ID, LD, and other disorders?
Researchers in New Zealand published the results of an epidemiological study of disabilities in that country, called “Aotearoa” in the aboriginal Maori language. The report, authored by Karen Tustin, Judith Adams, Nick Bowden, Helena McAnally, Andrew Wicken, Barry Taylor, and Fiona Turnbull of the University of Otago, was entitled “Kanorau ā-roro Neurodevelopmental conditions in children and young people in Aotearoa.”
Professor Turnbull’s team integrated data from national data bases about children and youths in New Zealand who had any of the following DSM diagnoses: (a) Attention deficit/hyperactivity disorder (ADHD), (b) Autism spectrum disorder (ASD), (c ) Intellectual disability (ID), (d) Foetal alcohol spectrum disorder (FASD), (e) Communication or language disorders (CLD), (f) Specific learning disorders (in reading, mathematics, or writing; SLD), and (g) Motor disorders (also referred to as developmental coordination disorder). They analyzed demographic data from March 2025 to ascertain estimated prevalence of the disorders by sex, age, geographic location, etc.
The report included this summary of its key findings:
Patterns of identified diagnoses of neurodevelopmental conditions in Aotearoa [New Zeland] broadly mirror those observed in other high-income countries, with an increasing apparent prevalence rate driven mostly by rising rates of ADHD and autism. International studies suggest that 8% of children and adolescents meet criteria for ADHD and 1–2% for autism, although reported prevalence varies widely depending on diagnostic practices, service access, and cultural context. Aotearoa’s service-identified rates of ADHD (2–4%) and autism (1%) in children and young people are lower than international estimates, reflecting that the data measure only children who come into contact with health or disability services. This under-ascertainment is particularly evident for FASD and CLD.
The median age of children’s first recorded diagnosis of a neurodevelopmental condition is 6 years, with nearly 70% diagnosed between the ages of 3 and 8 years. Autism is typically identified earlier than are ADHD or ID.
In keeping with data shown elsewhere, apparent prevalence is highest among boys, who are nearly three times as likely as are girls to have a recorded diagnosis, particularly in the cases of ADHD and autism. Apparent prevalence is also influenced by socioeconomic factors. Children living in more socioeconomically deprived areas have higher recorded apparent prevalence rates than do those in wealthier areas and are also more likely to be diagnosed at younger ages, likely because only more severe cases reach services. That only the most severe cases are likely to be diagnosed suggests that, in reality, the gradient by deprivation is likely to be even steeper than we have shown.
What distinguishes Aotearoa from other countries is the marked ethnic gradient, highlighting inequities in access to assessment that are not always as visible in other jurisdictions. European children are most likely to have recorded diagnoses of neurodevelopmental conditions, while Pacific, Asian, and MELAA children are least likely. Tamariki Māori have intermediate levels of recorded diagnoses but are identified at slightly younger ages than are European children.
ADHD is the most common neurodevelopmental condition and accounts for approximately two-thirds of all recorded cases, but co-occurring conditions are common. Around one in four children and young people with recorded diagnoses of neurodevelopmental conditions live with two or more conditions. The most common combinations in younger children (0–14-year-olds) are ADHD and autism or autism and SLD. In young people (15–24-year-olds) they are ADHD and autism or ADHD and ID. Pacific and Asian children are more likely than are European children or tamariki Māori to have recorded diagnoses of multiple neurodevelopmental conditions.
This quotation represents only a part of the executive summary for the report. That summary continued with sections on “regional differences.,” “best practice—what works,” and “implications.” Please see the original report for those topics.
This overall report is accompanied by “snapshots” focused on individual DSM disorders. The admirable series of reports prepared by Professor Turnbull and her colleagues is available from Otago University, which has an archive listing them, and most of them are open access.
Professor Turnbull, the senior scientist on the report, has conducted extensive studies about neurodevelopmental disorders. See her faculty page from Otago University.
Readers may be interested in other coverage of the report:
The Paediatric Society of New Zealand published coverage in Scoop on 13 July 2026 under the headline, “Landmark Report Maps A National Picture Of Neurodevelopmental Conditions In Aotearoa.”
Writing for the New Zealand Herald on 12 July 2026, Ruth Dryfhout published “ADHD underdiagnosis in New Zealand revealed in landmark study” (paywalled).
Press release of 13 July 2026 from Newswire entitled “New Zealand’s first national report on ADHD and autism finds thousands of children are being missed.”
Reference
Tustin K, Adams J, Bowden N, McAnally H, Wicken A, Taylor B, & Turnbull F. (2025). Kanorau ā-roro: Neurodevelopmental conditions in children and young people in Aotearoa. New Zealand Child and Youth Epidemiology Service, University of Otago. https://www.otago.ac.nz/nzcyes