Diagnoses of adult autism in Britain have increased tenfold since 2010, according to one of the largest studies of its kind, published in BMJ Mental Health. Researchers analyzed health records for over 33 million adults across the UK and Sweden between 2010 and 2023.
The study found that the rate of new autism diagnoses rose from 0.6 to 6.4 per 10,000 person-years during the study period. This equates to an increase from fewer than one in 10,000 adults receiving a new diagnosis at the start of the study to more than six in 10,000 by its end. In the UK specifically, nearly 4% of 16 to 20-year-olds received an autism diagnosis, a figure higher than previous estimates.
The trend appears to be largely driven by young women, with newly diagnosed adults being significantly more likely to have a history of mental health conditions. In the UK, the proportion of those diagnosed with autism who also had a previous diagnosis of anxiety rose from approximately 29% in 2010 to 58% in 2023. Rates of depression and ADHD among the newly diagnosed also increased.
Concurrently, conditions traditionally associated with autism, such as epilepsy and intellectual disability, became less common among those receiving new diagnoses, suggesting a shift in the characteristics of adults being diagnosed. The researchers noted that the profile of adults receiving an autism diagnosis has "changed dramatically" since 2010.
Experts are divided on the reasons behind this surge. Some suggest it reflects cultural shifts in the understanding and application of the autism label, while others argue it indicates a greater recognition and improved diagnostic practices, particularly for women who may have previously been overlooked. Professor Dame Uta Frith, an autism research pioneer, indicated that the rise might hint at cultural changes rather than biological ones. Conversely, others, like Rachel Moseley, principal academic in psychology at Bournemouth University, believe the study highlights evolving diagnostic practices and that this does not necessarily imply overdiagnosis.
The researchers themselves proposed that the increase could be attributed to better awareness, public discussion, and changes in how autism is diagnosed. However, concerns have also been raised about the influence of private clinics and their marketing strategies potentially leading to unnecessary diagnoses in vulnerable adults seeking self-understanding. Despite these concerns, specialists emphasize that many autistic adults genuinely require a diagnosis to access necessary support for their intertwined mental health and developmental conditions.