Epidemiological research shows that in recent years the prevalence of Autism Spectrum Disorder (ASD) has been increasing. Boys are diagnosed around four to five times more often than girls.

When looking at different regions of the world, the reported prevalence of autism is approximately 0.4% in Asia, 1% in the Americas, 0.5% in Europe, 1% in Africa and 1.7% in Australia (Salari et al., 2022). Figures can vary greatly between individual countries. For example, reported prevalence ranges from 0.02% in China to 3.66% in Sweden.

It is important to understand that these differences do not necessarily mean there are fewer autistic children in China or more in Sweden. Prevalence rates are influenced by many factors, and numbers alone may not fully reflect the real situation in each country. Several factors affect how autism prevalence is recorded. These include:

1. Diagnostic criteria – Different countries may use different screening and diagnostic tools. Some may apply stricter criteria, meaning only children with more noticeable characteristics receive a formal diagnosis, resulting in lower reported prevalence.
2. Access to healthcare – In countries with well-developed healthcare systems, children are more likely to be identified and diagnosed at an earlier stage. In areas with limited resources, many children may remain undiagnosed.
3. Public awareness – Greater understanding of autism among parents, teachers and healthcare professionals can lead to more children being assessed and supported.

Social and cultural factors also play an important role. In some cultures, developmental differences and mental health remain sensitive topics. Parents may feel hesitant about seeking assessment or support for their child, which can lead to under-reporting. In contrast, in countries where neurodiversity is more widely recognised and accepted, families and schools may be more proactive in identifying and supporting autistic children, leading to higher diagnosis rates.

Cultural expectations can also influence how children's behaviour is interpreted. For example, in some Asian cultures there is a strong emphasis on respecting elders and authority. In contrast, in Western cultures, greater emphasis may be placed on independence and self-expression. A child who is considered quiet, obedient and well-behaved in a Chinese community might be viewed in a Western setting as having social communication differences. Conversely, a child described as lively and outgoing in a Western country might be seen as overly active in a more traditional Asian context.

Regarding age of diagnosis, van't Hof et al. (2021) found that the current average age of autism diagnosis is around five years old. When focusing only on children under the age of ten, the average age of diagnosis is approximately three and a half.

Both research teams emphasised the same key message in their conclusions: early identification is crucial. Recognising autism at an early stage allows children to access support and intervention sooner, giving them the best possible opportunity to thrive.

References

Salari, N., Rasoulpoor, S., Rasoulpoor, S., Shohaimi, S., Jafarpour, S., Abdoli, N., ... & Mohammadi, M. (2022). The global prevalence of autism spectrum disorder: A comprehensive systematic review and meta-analysis. Italian Journal of Pediatrics, 48(1), 1–16.

van't Hof, M., Tisseur, C., van Berckelear-Onnes, I., van Nieuwenhuyzen, A., Daniels, A. M., Deen, M., ... & Ester, W. A. (2021). Age at autism spectrum disorder diagnosis: A systematic review and meta-analysis from 2012 to 2019. Autism, 25(4), 862–873.