Science & research

A large systematic review evaluated studies from 34 countries: as a median across the studies, the figure was about 1 in 100 children. The individual studies, however, come to very different results; the authors attribute this, among other things, to how well known autism is in a region and how well assessment is available. The numbers therefore cannot simply be read as the "true" prevalence.

In detail: How common is autism?

Autism has a strong hereditary component: twin and family studies estimate that differences between people in autism are largely explained by genetic factors. There is no single "autism gene"; rare gene variants with a large effect and common variants with a small effect each contribute to the risk. For the earlier idea that "cold" parenting causes autism, there is no scientific basis.

In detail: Causes of autism: what research knows

In Germany there are two major S3 guidelines on autism: Part 1 on diagnostics and Part 2 on therapy. Both were developed interdisciplinarily and are intended for children, adolescents and adults. According to the overview of the professional society DGKJP, the therapy guideline was valid "until 23.03.2026" and the diagnostics guideline "until 04.04.2021"; both have thus expired. Their contents do not automatically become wrong, but formally they no longer count as the current state.

In detail: The S3 guidelines on autism: content and validity status

A meta-analysis found a ratio of about 4.2 to 1; in high-quality studies it was closer to 3 to 1, and the authors saw indications that girls are less often diagnosed although they meet the criteria. A Swedish register study found that the ratio evens out with increasing age at diagnosis. Why this is so has not been clarified.

In detail: Autism and sex/gender in research