Study finds UK autism diagnoses shifting towards people with mental health conditions

The study, conducted by researchers from the University of Bristol and Avon and Wiltshire Mental Health Partnership NHS Trust in collaboration with Swedish colleagues, analysed records of 24.5 million UK adults. It found the proportion of newly diagnosed autistic adults with prior epilepsy fell from 10 per cent in 2010 to 4 per cent in 2023. Over the same period, those with a history of anxiety rose from 28.7 per cent to 58.3 per cent.

The rise was most pronounced among 16 to 20 year olds and women, and among white people compared to other ethnicities. The researchers said the increase in female diagnoses “may indicate an improved recognition of female presentations of autism, including the use of masking and camouflaging behaviours, addressing historic underdiagnosis”.

The team outlined several potential explanations for the changing profile. They noted that conditions like anxiety have also increasingly been diagnosed among adults without prior autism diagnoses. They said changes in diagnostic manuals may make clinicians more willing to recognise co-occurring conditions, and that it is possible there is greater appreciation of nuanced forms of autism that may previously have been labelled as other conditions. However, the team said a greater tendency to misattribute features that are typical of other conditions to autism cannot be ruled out.

Dr Monique Botha, associate professor in social and developmental psychology at Durham University, said the trends may reflect “the cumulative consequences of historical diagnostic inequalities rather than changing diagnostic boundaries”. She said the study demonstrates “a changing diagnosed population, not declining diagnostic validity, and these conclusions should not be conflated”. Botha said autistic adults are more likely to have depression and anxiety, and that these difficulties cannot be considered independently of social determinants including discrimination and exclusion.

The study lands in the wake of a UK Government-ordered review published last month that warned the country is at a “tipping point” over the misdiagnosis of ADHD and autism. That review’s chairman, Professor Peter Fonagy of UCL, pointed to pressure from private providers and argued that overdiagnosis risked “over-medicalisation” of ordinary life experiences. He said “life has become harder” for young people, driven by uncertainty and reduced belonging.

Whatever the cause of the trends, the research team stressed that “efforts will need to be made to recognise and address the needs (of autistic people) with appropriate support”.