This project focused on the experiences and challenges to older autistic people living in England, exploring diagnosis, and mental and physical health in particular.

• To understand how often autism goes undiagnosed in people aged 50 and over, and whether diagnosis rates differ by gender, socioeconomic status, and ethnicity.  

• To examine the physical and mental health needs of older autistic people, and whether they receive high-quality healthcare.  

• To explore the mental health needs of older autistic people, and how these needs arise.  

Many autistic people in England have never been formally diagnosed with autism, despite significant challenges in their daily lives. This means that large numbers of people are missing out on vital support. Recent research suggests that many autistic adults may be undiagnosed, particularly those aged over 50. 

An autism diagnosis can be life changing because it would make it easier for people to access support and reasonable adjustments in important aspects of their lives, such as healthcare, education, and employment. Without a diagnosis, autistic adults may not receive these adjustments or access to services, which can lead to poorer mental and physical health. The current services are not well designed to support them.  

This project addressed an important gap in research about autism in later life and worked towards reducing barriers for autistic people.  

The project strongly aligned with our Moonshot Vision towards a society that works for autistic people, specifically in its ambition to improve diagnosis and have autistic people’s needs recognised and supported.  

Throughout this project, the researchers worked closely with an advisory group of autistic people and us, the National Autistic Society to make sure the research reflected lived experience and priorities.  

The project included several simultaneous studies. The work focussing on diagnosis consisted of four parts: 

1. Estimate how many people in England have an autism diagnosis  

This study used anonymised NHS primary care data records from more than five million people registered with GP practices in England between 2000 and 2018. From these records, the researchers identified people who had been diagnosed with autism, including autism, Asperger’s syndrome, and pervasive development disorder.   
 

2. Explore who is more or less likely to be diagnosed  

The researchers also looked at demographic information, such as age, gender, intellectual disability diagnosis, and socioeconomic deprivation. This helped the researchers gain a better insight into factors impacting diagnosis rates.  
 

3. Estimate how many autistic people may be undiagnosed 

The researchers compared the number of diagnosed individuals in NHS records with estimates of how common autism was in the general population. They used two different estimates: 

• A lower estimate of around 1% which is commonly used in older community studies.  
• A higher estimate of around 3% based on diagnosis rates seen in young people aged 10-19 in their dataset, as this age group is more likely than others to be identified and diagnosed.  

4. Analyse trends over time and differences across groups 

The researchers calculated how new autism diagnoses changed over time. They looked at trends in diagnosis rates per year and examined how these varied by age, gender, intellectual disability, and socioeconomic deprivation. This helped the researchers understand how these factors influence the likelihood of receiving a diagnosis.  

• There may be approximately 750,000 undiagnosed autistic people aged 20 and above in England. This would make the total autistic population in England over 1.2 million people.  
• Autism diagnoses rates were much higher in children (2.94%) than older adults (0.02%).  
• Autistic people, especially those with an intellectual disability, had higher death rates and shorter life expectancies than non-autistic people. 
• Autistic adults without intellectual disability were more likely to experience self-harm, anxiety, depression, and substance use than non-autistic people. 
• Complementary qualitative work suggested: 
  • Autistic women reported that stigma and stereotypes about autism, along with negative healthcare experiences, reduced their confidence in seeking help and made navigating the healthcare system difficult.  
  • Older autistic adults (65+) reported unique challenges in accessing healthcare because services don’t consider their lifelong experiences of social exclusion, as well as anxiety and sensory overload.  
• The researchers also built on an existing cohort study called PROTECT, which looks at the mental and physical health of 22,000 mid-life and older adults over time. They added measures of autistic traits so that they could study the long-term mental and physical health outcomes of people who don’t have an autism diagnosis but have high autistic traits.  
• Using data from PROTECT, the researchers have started publishing work. For example, one study found that visual working memory does not change more over time for those with high autistic vs nonautistic traits. This suggests that having higher autistic traits was not linked to greater cognitive decline.  

• Joshua Stott (Co-Principal Investigator) is a Clinical Psychologist and Professor at University College London. His research focuses on ageing, autism, and neurodiversity.  
• William Mandy (Co-Principal Investigator) is a Professor at University College London. His research is aimed at helping autistic people live more enjoyable and fulfilling lives.  

The wider project team included collaborators from University College London, Goldsmiths University, Queen Mary University London, University of Exeter, King’s College London, and ourselves.  

Our charity helped to ensure that autistic people’s voices and experiences shaped the project from start to finish. We brought together an advisory group of four autistic people with a range of relevant lived experience. The group met with the research team periodically, shared their insights and guided each stage of the work.  

We also contributed to regular project team discussions, reviewed key documents, and shared project updates and findings.