Autism diagnoses have risen sharply—by eightfold in the UK from 1998 to 2018—but this doesn’t necessarily mean more people are autistic now. Instead, the increase reflects changes in how autism is defined and diagnosed, especially broader diagnostic criteria and greater awareness.
Historically, autism was narrowly defined and seen mostly in boys with high support needs. But since the 1990s, the definition has expanded to include conditions like Asperger’s syndrome and PDD-NOS, now all grouped under autism spectrum disorder (ASD). This wider “autism net” captures more people, especially women, girls, and adults with fewer visible support needs, many of whom were previously misdiagnosed with conditions like anxiety or OCD.
The diagnosis surge among women and adults reflects decades of underdiagnosis and growing recognition of traits like masking (hiding symptoms to fit in). Research now acknowledges that many lived undiagnosed for years due to outdated assumptions.
Why this matters:
- Raises awareness of autism’s broad spectrum, especially in underrepresented groups.
- Reduces stigma by showing many autistic people live undiagnosed for years, not that there’s a “sudden epidemic.”
- Promotes early support, especially for women and adults who were previously overlooked.
- Encourages accurate diagnosis, avoiding mislabels like anxiety or borderline personality disorder.