A major review from King’s College London has revealed that most autistic adults over the age of 40 have never received a diagnosis, with the proportion even higher among those over 60. The research, published in the Annual Review of Developmental Psychology, found that older autistic people are at greater risk of poor mental and physical health compared to their non-autistic peers, as well as facing difficulties with relationships, work and general wellbeing.

The findings suggest that undiagnosed autistic adults are far more likely to struggle with depression, anxiety and other health problems. Those with high autistic traits were also reported to be six times more likely to have suicidal thoughts or engage in self-harm. Alongside this, older autistic adults were found to encounter more barriers in accessing healthcare, often due to systems not being designed with their needs in mind, including communication differences, sensory sensitivities and inconsistent support from professionals.

The review also highlighted higher rates of chronic conditions such as cardiovascular disease, immune disorders, neurological problems and gastrointestinal issues. These challenges are compounded by risks linked to ageing, including Parkinson’s disease, arthritis, cognitive decline and dementia. Social isolation, limited networks and a lack of tailored resources further affect quality of life.

Researchers stressed that underdiagnosis has left many autistic adults without appropriate recognition or support throughout their lives, making them particularly vulnerable as they age. They argue that autism needs to be fully integrated into ageing research, with greater involvement from autistic communities to ensure services and policies reflect their lived experiences.