Most adults in the UK aged 40 and above who are on the autism spectrum remain undiagnosed, according to new research.
A study from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King’s College London reanalysed healthcare data from 2018 and found that 91.45% of men and 79.48% of women aged 40–59 with autism have not received a formal diagnosis. The overall under-diagnosis rate in this age group is estimated at 89.29%.
The gap widens with age. Among people over 60, 96.29% of men and 97.19% of women with autism are thought to be undiagnosed, equating to an overall rate of 96.51%. By comparison, the rate is significantly lower in younger groups—52.54% among those aged 20–39 and 23.34% for those under 19.
Tim Nicholls, assistant director of policy at the National Autistic Society, said the findings reflect an issue his organisation hears about daily.
“There are high numbers of undiagnosed autistic adults, and going through life without a diagnosis has a major impact on many aspects of their lives,” he said. “Autism assessments can be the first step to understanding people’s needs, and a diagnosis can be life-changing and, in some cases, lifesaving.”
To shed light on how autism may present later in life, clinical psychologist Dr. Lisa Williams, founder of The Autism Service, outlined seven subtle autism symptoms that often go unnoticed in adults over 40:
Reliance on routine – Older autistic adults may cling to structured daily habits, finding comfort in predictability and experiencing stress when routines are disrupted.
Intense, specific interests – Deep, lifelong passions for certain subjects or hobbies may dominate free time and conversations.
Sensory sensitivities – Heightened reactions to noise, light, smells, or textures can persist well into later life, making certain environments uncomfortable.
Struggles with change – Major life transitions, such as moving house or adapting to new technology, can trigger heightened anxiety.
Difficulty with social rules – Challenges in interpreting unwritten norms like eye contact, body language, or humour may leave adults feeling out of step socially.
Relationship challenges – Romantic relationships may be difficult to initiate or maintain, with issues around communication, intimacy, or a preference for independence.
Workplace integration difficulties – While many excel in specialised roles, adapting to office politics, group dynamics, or frequent change can be harder without supportive management.
Experts stress that recognising these signs and seeking assessment is vital, as a diagnosis later in life can provide clarity, support, and improved quality of life.
YOU MAY ALSO LIKE
New Drug Shows Potential to Reverse Autism Symptoms in Mice
