Nearly 90% of autistic adults over 40 years are undiagnosed

The majority of autistic adults aged over 40 remain undiagnosed, with the numbers even higher in the over-60 population, according to new research from King’s College London.

In the largest review of its kind, the researchers also found that middle-aged and older autistic adults are facing higher rates of mental and physical health conditions than non-autistic adults of the same age, alongside challenges with employment, relationships and wellbeing.

Older adults with high autistic traits are also six times more likely to experience suicidal ideation, thoughts of self-harm, and self-harm.

The review, published in the Annual Review of Developmental Psychology, re-analysed previous research on UK healthcare record data from 2018 and conducted a narrative review to understand whether autistic people have different ageing patterns from the general population.

Greater healthcare barriers for older autistic people

It found that middle-aged and older autistic people are likely to experience greater healthcare barriers, increased early mortality, and more challenges with life transitions. They also experience more adverse life events, more cognitive difficulties, potential dementia risk, lower quality of life, greater social isolation, and lower social support.

They also face barriers to receiving healthcare support, as they must navigate systems that are not designed for them. These barriers included aspects associated with autistic traits, such as communication differences and sensory sensitivities, as well as concerns about continuity of care, uncertainty about which services to access, and limited clinician understanding of autism in adulthood.

This is despite increased physical problems, including immune diseases, cardiovascular disease, neurological disorders, gastrointestinal disorders, anxiety and depression, as well as conditions associated with older age, such as Parkinson’s disease, cognitive disorders, osteoporosis and arthritis.

The authors said that while cohort effects and high rates of underdiagnosis may influence these findings, it is evident that ageing autistic people likely require tailored support to improve their outcomes.

They added that the review identifies key areas for future research, proposing an improved conceptual framework that better integrates autism into the field of ageing research. It also highlights the importance of meaningful engagement with the autistic community and stakeholders in developing effective resources for this historically underserved population.

Many autistic adults have never received the proper support

Although research on ageing in autistic populations has increased nearly fourfold since 2012, only 0.4 per cent of research on autism since 1980 has focused on people in midlife or older age. The review found that 89% of people aged 40-59 years and 97% of people aged 60+ are estimated to be undiagnosed.

Dr Gavin Stewart, British Academy Postdoctoral Research Fellow at the IoPPN and lead author of the review, said: “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.”

Alison Bloomer

Alison Bloomer is Editor of Learning Disability Today.

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