Introduction
For many years, autism was viewed primarily as a childhood condition. As a result, countless people reached adulthood—and even older age—without ever receiving an autism diagnosis. Today, increasing awareness of how autism presents across the lifespan means that more people are being identified in their 40s, 50s, 60s, 70s and beyond.
The simple answer is yes, you can be diagnosed with autism in later life. In fact, research suggests that a substantial number of older autistic adults remain undiagnosed, meaning that many people are only now beginning to understand themselves through the lens of autism.
Autism Is a Lifelong Neurodevelopmental Condition
Autism Spectrum Disorder (ASD) is a neurodevelopmental condition characterised by:
- Persistent differences in social communication and interaction
- Restricted or repetitive patterns of behaviour, interests or activities
- Sensory differences
- Symptoms that have been present since early development, even if they were not recognised at the time
Although autism begins in early childhood, it may not always be identified during childhood. Some people learn ways to compensate for their differences, whilst others are mistakenly diagnosed with anxiety, depression, personality disorders, obsessive-compulsive disorder (OCD), eating disorders or other conditions.
A diagnosis may therefore not occur until much later in life.
How Common Is Late Diagnosis?
Recent research from the Institute of Psychiatry, Psychology & Neuroscience at King’s College London suggests that late diagnosis is extremely common among older adults.
A 2025 review of ageing and autism found that:
- Approximately 89% of autistic adults aged 40–59 in the UK are estimated to be undiagnosed
- Approximately 97% of autistic adults aged 60 years and over are estimated to be undiagnosed
- Overall, between 89% and 97% of autistic adults aged over 40 may not have received a formal diagnosis
These findings suggest that thousands of older autistic adults may have spent most of their lives without understanding the reasons behind their experiences.
Researchers from King’s College London noted that this high level of underdiagnosis may leave many autistic adults without access to appropriate support, reasonable adjustments or autism-informed healthcare.
Why Was Autism Missed in Older Generations?
Autism Was Understood Differently:
Until relatively recently, autism was associated primarily with children who had significant speech delays or learning disabilities.
Earlier diagnostic criteria did not adequately recognise:
- People with average or above-average intelligence
- Women and girls
- Individuals who developed speech on time
- People who were able to mask their difficulties
Many older adults simply did not fit the stereotypes that existed when they were growing up.
Masking and Camouflaging:
A growing body of research shows that many autistic people consciously or unconsciously learn to hide their differences.
Common masking strategies include:
- Copying other people’s behaviours
- Rehearsing conversations before social situations
- Forcing eye contact
- Suppressing stimming behaviours
- Closely observing social rules without fully understanding them
Masking can make autism less visible to professionals, family members and teachers, particularly in academically able individuals.
Co-Occurring Mental Health Difficulties:
Many autistic adults first seek professional help because of:
- Anxiety
- Depression
- Burnout
- Chronic stress
- Social difficulties
- Relationship problems
For some, these conditions are treated for years before anyone considers whether autism may be underlying their difficulties.
What Leads Someone to Seek a Diagnosis Later in Life?
Many adults describe a specific event or life stage that prompts them to explore autism.
Common triggers include:
Having an Autistic Child:
One of the most common pathways to diagnosis occurs when a parent learns about autism through their child’s assessment and begins recognising the same traits in themselves.
Workplace Difficulties:
Increasing workplace demands may expose difficulties with:
- Sensory environments
- Social expectations
- Organisational change
- Unwritten workplace rules
This can lead individuals to question why they seem to struggle with situations that others manage more easily.
Relationship Challenges:
Some people seek assessment after difficulties in:
- Romantic relationships
- Friendships
- Family interactions
A diagnosis may help explain lifelong misunderstandings and communication differences.
Menopause and Perimenopause:
Research and clinical experience suggest that some autistic women first recognise their autistic traits during perimenopause or menopause.
The reduction in energy available for masking, alongside hormonal changes and increased sensory sensitivity, can make long-standing autistic differences more noticeable.
Retirement or Major Life Changes:
Later-life transitions such as:
- Retirement
- Bereavement
- Ill health
- Changes in routine
can reduce established coping strategies and reveal autistic traits that were previously managed successfully.
What Are the Signs of Autism in Older Adults?
Although every autistic person is different, commonly reported experiences include:
Social Differences:
- Feeling different throughout life
- Difficulty understanding social expectations
- Feeling exhausted after social interaction
- Preferring smaller groups or one-to-one conversations
- Struggling with small talk
Communication Differences:
- Being perceived as direct or blunt
- Difficulty interpreting sarcasm or implied meanings
- Preferring clear and unambiguous communication
- Rehearsing conversations in advance
Sensory Differences:
- Sensitivity to noise, light, smells or textures
- Becoming overwhelmed in busy environments
- Needing quiet recovery time after sensory overload
Preference for Predictability:
- Feeling uncomfortable with unexpected change
- Strong routines and habits
- Extensive planning before events
Intense Interests:
- Long-standing interests pursued with exceptional depth and enthusiasm
- Acquiring expert-level knowledge in specific subject areas
What Does an Autism Assessment Look Like in Later Life?
There is no upper age limit for an autism assessment.
A comprehensive adult assessment typically involves:
- A detailed developmental history
- Discussion of childhood experiences
- Exploration of current strengths and difficulties
- Semi-structured clinical interviews
- Multidisciplinary diagnostic review
Because autism must be present from early development, clinicians will often explore childhood experiences wherever possible. However, the absence of school reports or living relatives does not automatically prevent assessment.
Experienced clinicians can often gather sufficient information through interviews and collateral evidence.
What Are the Benefits of a Later-Life Diagnosis?
Many adults describe their diagnosis as transformative.
Common benefits include:
Greater Self-Understanding:
Many people report finally understanding:
- Why they felt different
- Why social interactions have been difficult
- Why they experience certain sensory challenges
Reduced Self-Blame:
A diagnosis can shift someone’s perspective from:
“What’s wrong with me?”
to
“This is how my brain works.”
Improved Mental Health
Research suggests that receiving a diagnosis can promote:
- Self-acceptance
- Improved identity development
- Better understanding of personal needs
- More appropriate support
Access to Adjustments and Support:
A diagnosis may facilitate:
- Workplace adjustments
- Access to support services
- Autism-informed therapy
- Improved healthcare interactions
Validation of Lifelong Experiences:
Many adults describe the greatest benefit as simply having an explanation that makes sense of decades of experiences.
Is It Ever Too Late to Be Diagnosed?
No.
Autism does not disappear with age, and there is no point at which assessment becomes “too late”.
Whether someone is 25, 55 or 85, a diagnosis can still provide valuable insight into lifelong patterns of thinking, communicating and experiencing the world.
The growing evidence from King’s College London showing that up to 90% of autistic adults over 40 remain undiagnosed highlights how many people may still benefit from assessment and support later in life.
Conclusion
Autism is a lifelong neurodevelopmental condition, but many autistic people were not recognised when they were growing up. Greater awareness of masking, female presentations of autism and adult autism has led to increasing numbers of later-life diagnoses.
Research from King’s College London suggests that the majority of autistic adults over 40 may remain undiagnosed, meaning there are many people whose experiences have never been properly understood. For these individuals, an autism assessment can provide clarity, self-understanding and access to support that may have been unavailable for much of their lives.
References
American Psychiatric Association (2022) Diagnostic and Statistical Manual of Mental Disorders (5th ed., text rev.). Washington, DC: American Psychiatric Publishing.
Happé, F. and Stewart, G.R. (2025) Ageing Across the Autism Spectrum. Annual Review of Developmental Psychology, 7, pp. 4.1–4.24.
O’Nions, E., Petersen, I., Buckley, C., et al. (2023) ‘Autism diagnosis rates and age-related identification patterns in the UK population’, Journal of Child Psychology and Psychiatry, 64(10), pp. 1452–1463.
Stewart, G.R. and Happé, F. (2025) ‘Ageing across the autism spectrum: A narrative review’, Annual Review of Developmental Psychology, 7, pp. 4.1–4.24.
World Health Organization (2023) International Classification of Diseases 11th Revision (ICD-11). Geneva: WHO.
