For many autistic adults, the path to understanding our neurodivergence follows a familiar pattern: years of seeking help from mental health professionals, receiving various diagnoses and treatments with mixed results, and continuing to struggle with unexplained challenges. And then, finally autism is identified. Suddenly, everything makes sense — our life, our experiences, our difficulties and more.
This journey raises numerous questions: How often is autism missed? How often is it misdiagnosed? How long does it typically take for mental health services to recognize autism in adults who are seeking support? Are there specific autistic traits that lead to this delay? At what age are these autistic adults finally diagnosed? Does it differ for men vs women?
A Study That Sheds Light
A 2021 study (linked below) examined these very issues by analyzing the experiences of a sample of autistic adults who had been referred to mental health services. These individuals, aged 18-43 and had no intellectual disability or verbal impairment. Researchers collected extensive background information for each person (mental health reports, patient and relative interviews etc.) and also had participants complete two standard autism questionnaires.
The findings were striking:
- 75% of participants weren’t diagnosed with autism at their first mental health evaluation.
- Males were, on average, first referred to mental health services at age of 12, versus 21 for females.
- Men were diagnosed with autism at an average age of 20, versus 29 for women.
- The average diagnostic delay — time between first mental health contact and autism diagnosis — was 8 years for both men and women.
Gender Differences
It’s significant that the delay in diagnosis was the same for both genders, yet women were diagnosed nearly a decade later than men. The reason? They generally entered the mental health system much later.
This reflects some important patterns:
- Autistic traits in women and girls can present differently, often going unnoticed for longer. A boy might display obvious behavioural issues; a girl may become a perfectionist weighed down by anxiety.
- Certain autistic traits in women can often be seen as personality traits (such as “sensitive” or “shy”) rather than attributable to autism; or even typical — for example, a love of animals without considering the depth and intensity of the interest.
- Women and girls are better at masking their difficulties, making it harder for others to spot the underlying autism.
Why the Delay Happens
The autism questionnaire results gave clues about which traits were linked to longer delays — and these were different for men and women.
For men, a longer delay was linked to stronger skills in verbal communication, empathy, and flexibility — in other words, less apparent challenges in these areas meant they were harder to identify as autistic.
For women, a longer delay was linked to higher “attention to detail” scores. A later age at diagnosis was associated with greater struggles in verbal communication, intense special interests, and rumination (spending excessive time thinking about the same topic or replaying experiences).
For women, this may seem counter-intuitive — stronger autistic traits leading to later diagnosis — but the study suggests this happens because these traits are often misinterpreted as signs of other mental health conditions.
The Problem of Misdiagnosis
This study shows that 45.5% of the women were initially misdiagnosed versus only 17.9% of the men. The most common misdiagnosis for the females was personality disorders, whilst, for men it was ADHD.
- Attention to detail may be mistaken for obsessive-compulsive traits, perfectionism, or anxiety-related behaviours, rather than recognised as part of an autistic profile.
- Verbal communication struggles, intense interests, and rumination can be reframed as symptoms of borderline personality disorder, anxiety disorders, or obsessive thinking.
- Women in the study who were misdiagnosed showed higher sensory reactivity than men. Sensory overload is linked to self-injurious behaviours in autistic people, which overlaps with how borderline personality disorder is often characterised.
In short, these autistic traits are reframed through a psychiatric lens and autism is overlooked.
What This Means for Autistics
We keep going — often struggling in silence — until cracks appear and life deteriorates enough to seek medical help. But that help may not bring the answers we expect. Instead, we may be given treatments that only partly address our struggles, or worse, receive a diagnosis that doesn’t fit at all.
This can lead to years, even decades, of unnecessary stress, anxiety, depression, physical health issues, and social or work difficulties. Only once autism is identified can we start to truly understand ourselves and get support that fits our needs.
What it Means for Mental Health Service Providers
Mental health professionals need more than just general autism awareness. Training must:
- Highlight the diversity of autism presentations, including how they differ by gender.
- Focus on avoiding the common tendency to misinterpret autistic traits as symptoms of other disorders.
- Cover the frequent co-occurrence of depression, anxiety, and other psychiatric conditions in autistic populations.
A practical first step? Have all adults referred to mental health services complete an autism screening questionnaire. While not perfect, it’s a simple tool that can flag when autism should be seriously considered.
Study: Gender Differences in Misdiagnosis and Delayed Diagnosis among Adults with Autism Spectrum Disorder with No Language or Intellectual Disability