Around 90% of middle-aged and older autistic adults are undiagnosed in the UK, new review finds

89 to 97 per cent of autistic adults aged 40+ years are undiagnosed in the UK, according to the largest review of its kind which was conducted at the Institute of Psychiatry, Psychology & Neuroscience at King’s College London. The review indicated 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.

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 researchers collated the research to date and conducted a narrative review to understand whether autistic people have different ageing patterns to the general population.

The review, published in the Annual Review of Developmental Psychology, provides a summary of research in this area, highlighting the critical need for more studies to find ways to improve outcomes for this population.

The review was supported by the British Academy and National Institute for Health and Care Research (NIHR) Maudsley Biomedical Research Centre. It highlights substantial challenges for autistic adults in midlife and older age across multiple areas, and identifies barriers to receiving appropriate healthcare support in older adulthood.

Over 89 per cent of autistic adults aged 40+ are undiagnosed

Although people do not ‘grow out’ of autism, there is a large discrepancy in diagnosis rates between younger and older generations. The authors of the review re-analysed previous research on UK healthcare record data from 2018 and found that 89 per cent of people age 40-59 years and 97 per cent of people age 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.”

Higher risk of almost all physical and mental health conditions

The review emphasised a variety of challenges autistic adults in midlife and older age face. The collated evidence shows that middle-aged and older autistic adults have higher rates of almost all physical and mental health conditions compared to non-autistic adults. These include 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.

Particularly concerning findings indicate that older adults with high autistic traits are six times more likely to experience suicidal ideation, thoughts of self-harm, and self-harm. The collated findings also suggest that autistic adults were four-times as likely to have a diagnosis of early onset dementia compared to non-autistic people. Average life expectancy differed by six years, with autistic people living to age 75 years compared to 81 years for non-autistic people. The authors warn that these figures may be skewed due to high rates of underdiagnoses.

The review noted autistic adults experience barriers to receiving healthcare support, having to navigate systems 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.

In addition to health-related outcomes, poorer outcomes were also seen across employment prior to retirement, relationships and quality of life. There were high rates of social isolation among adults with autism, and the research indicates that strong social support is linked to better quality of life.

Professor Francesca Happé, Professor of Cognitive Neuroscience at the IoPPN and co-author of the review, said:

“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.”

The review particularly highlighted a lack of longitudinal research which follows autistic people over time to directly measure effects of ageing. The researchers emphasise that more research is needed to better understand the experiences of autistic people in midlife and older age, with the aim of improving outcomes for autistic adults as they age.

Ends

“Ageing across the Autism Spectrum – A narrative review” (Gavin Stewart and Francesca Happé) was published in the Annual Review of Developmental Psychology. DOI: 10.1146/annurev-devpsych-111323-090813.

For more information, please contact Franca Davenport (Senior Communications and Engagement Manager at NIHR Maudsley Biomedical Research Centre). Em: franca.davenport@kcl.ac.uk, mob: +44 (0) 7976 918968

Notes to editors

About King’s College London and the Institute of Psychiatry, Psychology & Neuroscience 

King’s College London is amongst the top 35 universities in the world and top 10 in Europe (THE World University Rankings 2023), and one of England’s oldest and most prestigious universities.

With an outstanding reputation for world-class teaching and cutting-edge research, King’s maintained its sixth position for ‘research power’ in the UK (2021 Research Excellence Framework).

King's has more than 33,000 students (including more than 12,800 postgraduates) from some 150 countries worldwide, and some 8,500 staff. The Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King’s is a leading centre for mental health and neuroscience research in Europe. It produces more highly cited outputs (top 1% citations) on psychiatry and mental health than any other centre (SciVal 2021), and on this metric has risen from 16th (2014) to 4th (2021) in the world for highly cited neuroscience outputs. In the 2021 Research Excellence Framework (REF), 90% of research at the IoPPN was deemed ‘world leading’ or ‘internationally excellent’ (3* and 4*). World-leading research from the IoPPN has made, and continues to make, an impact on how we understand, prevent and treat mental illness, neurological conditions, and other conditions that affect the brain.

www.kcl.ac.uk/ioppn | Follow @KingsIoPPN on Twitter, Instagram, Facebook and LinkedIn

The National Institute for Health and Care Research (NIHR)

The mission of the National Institute for Health and Care Research (NIHR) is to improve the health and wealth of the nation through research. We do this by:

• Funding high quality, timely research that benefits the NHS, public health and social care;
• Investing in world-class expertise, facilities and a skilled delivery workforce to translate discoveries into improved treatments and services;
• Partnering with patients, service users, carers and communities, improving the relevance, quality and impact of our research;
• Attracting, training and supporting the best researchers to tackle complex health and social care challenges;
• Collaborating with other public funders, charities and industry to help shape a cohesive and globally competitive research system;
• Funding applied global health research and training to meet the needs of the poorest people in low and middle income countries.

NIHR is funded by the Department of Health and Social Care. Its work in low and middle income countries is principally funded through UK Aid from the UK government.

The British Academy

The British Academy is the UK’s national academy for the humanities and social sciences. We mobilise these disciplines to understand the world and shape a brighter future. We invest in researchers and projects across the UK and overseas, engage the public with fresh thinking and debates, and bring together scholars, government, business and civil society to influence policy for the benefit of everyone.  

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