What is really driving skyrocketing diagnoses of ADHD and autism

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By Michael Marshall

Is it an epidemic of overdiagnosis, or do the dramatic rises in autism and ADHD cases reflect the healthcare system – and society – starting to catch up to the reality of neurodivergence?

The numbers of people diagnosed with autism and attention deficit hyperactivity disorder (ADHD) have increased enormously over the last few decades.

The raw numbers are staggering. In the UK, the recorded number of autism diagnoses increased by 787% between 1998 and 2018, according to a study published in 2021. Likewise, UK diagnoses of ADHD shot up between 2000 and 2020, according to a 2023 study. Rates quadrupled among females under 18 and increased almost 20-fold in males aged over 18.

What explains these incredible rises in diagnosis? There is no evidence that either condition is becoming more common. While there may be some isolated overdiagnosis, overall the evidence suggests that both conditions actually remain underdiagnosed despite the growing numbers. Instead, the healthcare system, and society itself, are catching up to the reality of neurodivergence.