What Percentage of Adults Receive a Late Autism Diagnosis?

PostedNovember 6, 2025

UpdatedNovember 6, 2025

ByMy Patient Advice

Author: Beatrice Holloway, MSc | Reviewed by: Dr. Rebecca Fernandez, MBBS

The percentage of late autism diagnoses in adults is increasing, with more individuals recognising autism traits later in life. Recent studies suggest that up to one in three adults receive an autism diagnosis after the age of 18. This highlights a shift in understanding and diagnosis, as more adults seek assessment after years of living without a clear explanation for their challenges. This adult diagnosis stat reflects the growing awareness of autism in adulthood, where symptoms often present differently compared to childhood.

This rise in late diagnoses is partly due to greater prevalence data around adult autism and a wider recognition that autism can manifest in subtler ways in adulthood. Many adults may have been misdiagnosed or missed entirely during childhood, with symptoms overlooked or misattributed to other conditions.

Common Symptoms of Late Autism Diagnosis

In addition to social communication issues and sensory sensitivities, adults diagnosed later in life may also experience:

Difficulty with Change or Transitions:

Many adults with autism find it challenging to adapt to unexpected changes in routines or environments. This can cause anxiety or distress. Cognitive and behavioural strategies can help individuals manage these feelings and increase flexibility in their daily lives.

Intense Focus or Special Interests:

Adults with autism often develop deep, intense interests in specific topics. While this can be a strength, it may interfere with work or relationships if not properly managed. Support balancing these interests with everyday responsibilities can be helpful.

If you suspect you might be experiencing some of these signs, visit providers like Autism Detect for personal consultations to explore your options.

For a deeper dive into the science, diagnosis, and full treatment landscape, read our complete guide to late diagnosis in adults.

Beatrice Holloway, MSc

Author

Beatrice Holloway is a clinical psychologist with a Master’s in Clinical Psychology and a BS in Applied Psychology. She specialises in CBT, psychological testing, and applied behaviour therapy, working with children with autism spectrum disorder (ASD), developmental delays, and learning disabilities, as well as adults with bipolar disorder, schizophrenia, anxiety, OCD, and substance use disorders. Holloway creates personalised treatment plans to support emotional regulation, social skills, and academic progress in children, and delivers evidence-based therapy to improve mental health and well-being across all ages.

All qualifications and professional experience stated above are authentic and verified by our editorial team. However, pseudonym and image likeness are used to protect the author's privacy.

Dr. Rebecca Fernandez, MBBS

Reviewer

Dr. Rebecca Fernandez is a UK-trained physician with an MBBS and experience in general surgery, cardiology, internal medicine, gynecology, intensive care, and emergency medicine. She has managed critically ill patients, stabilised acute trauma cases, and provided comprehensive inpatient and outpatient care. In psychiatry, Dr. Fernandez has worked with psychotic, mood, anxiety, and substance use disorders, applying evidence-based approaches such as CBT, ACT, and mindfulness-based therapies. Her skills span patient assessment, treatment planning, and the integration of digital health solutions to support mental well-being.

All qualifications and professional experience stated above are authentic and verified by our editorial team. However, pseudonym and image likeness are used to protect the reviewer's privacy.