Researchers at the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King’s College London re-analysed UK healthcare records from 2018. They estimate that among middle-aged adults with autism (40–59), 91.45% of men and 79.48% of women are undiagnosed, with an overall underdiagnosis rate of 89.29%. Among those aged 60 to over 70, 96.29% of men and 97.19% of women are undiagnosed, with an overall rate of 96.51%. By comparison, undiagnosed rates are 52.54% for 20–39-year-olds and 23.34% for those under 19.

Dr Gavin Stewart, British Academy postdoctoral research fellow at the IoPPN, said the very high underdiagnosis estimates suggest that many autistic adults will have never been recognised as autistic, and will have not been offered the right support. “These very high underdiagnosis estimates suggest that many autistic adults will have never been recognised as being autistic, and will have not been offered the right support. This could make them more susceptible to age-related problems, for example being socially isolated and having poorer health. The high rates of underdiagnosis also mean that much of our research has systematically overlooked a large proportion of the autistic population, potentially skewing our understanding of how autistic people age, and leaving critical gaps in policy and services.”

Francesca Happe, professor of cognitive neuroscience at the IoPPN, added: “Understanding the needs of autistic people as they age is a pressing global public health concern. As autistic people age, the nature of the challenges they face changes. We must adopt a lifespan approach that funds long-term research, integrates tailored healthcare, and expands social supports so that ageing autistic people can live happy and healthy lives.” Researchers also suggest middle-aged autistic people are more likely to experience higher rates of conditions such as Parkinson’s disease, arthritis and heart disease, and to self-harm. They may face greater barriers to healthcare, lower quality of life and increased social isolation.