This year, in honour of World Autism Acceptance Month, we’re spreading awareness about late-diagnosed autism. Check out the "further information and resources" section at the end of this article, which includes links to content on how to get an autism diagnosis in British Columbia.

autistic pride flag
Autistic pride flag

Often thought of as a “disorder” of childhood, autism is a lifelong neurodevelopmental condition impacting the way a person processes sensory, social, emotional and cognitive information. While some research has indicated that the average age of autism diagnosis is slowly decreasing over time thanks to increased awareness and improvements in diagnostic measures and tools, a considerable number of autistic individuals are not diagnosed until their teens, early adulthood or even much later.

Autism diagnoses are currently categorized into levels 1 through 3, with level 1 indicating low support needs, level 2 indicating substantial support needs, and level 3 indicating very substantial support needs.

While a large body of evidence indicates that autism is genetic or hereditary, autism is highly heterogeneous. This means that autistic traits vary widely from person to person and can arise from different etiological or causal factors. As commonly stated in the autism community, “if you’ve met one autistic person, you’ve met one autistic person.”

Children with more pronounced autistic traits or with co-occurring intellectual disability tend to be diagnosed earlier, usually by the age of five. Additionally, male autistic individuals tend to be diagnosed earlier than their female autistic peers. Many who exhibit less pronounced autistic traits — or signs of level 1 autism (formerly known as high-functioning autism or Asperger syndrome) — are often not diagnosed in childhood. This delay in diagnosis can be associated with an increase in psychiatric misdiagnoses, unnecessary medication, and confusion and distress for both the individual and their families.

Why is autism missed?

Many autistic children and teens with average to high IQ may develop compensatory, “camouflaging” or “masking” behaviours to hide their difficulties with certain aspects of socializing and to downplay their sensory challenges. This process of compensating makes the individual appear neurotypical — another word for non-autistic — and involves the use of different neural or brain-based routes and psychological strategies to demonstrate typical or expected social skills and behaviours. A child or youth with compensatory behaviours may not know that they are compensating and, if asked, may say that they thought everyone engages in the same strategies to fit in.

Masking or camouflaging behaviours can include:

  • forcing oneself to make eye contact
  • suppressing repetitive physical movements (aka “stims”)
  • purposely not talking about one’s special interests with others
  • mimicking others’ behaviours, gestures and body language
  • creating scripts for small talk, though most autistics do not like small talk

“I’m really good at masking and people tell me that all the time whether they know it or not. When someone says to me that they never would’ve known that I was autistic if I hadn’t told them, or that I don’t seem autistic, what they’re really telling me is that I’m good at masking,” says Kate Kahle, an autistic college student who recently presented on autism in women and girls.

However, these compensatory behaviours can be so developed and habitual in some autistic individuals that even psychologists well-trained to detect autistic traits would not be able to tell. While compensatory behaviours tend to correspond with living independently, successfully attending school and maintaining careers, studies have shown that they may also result in poor mental health over time. The act of masking autistic traits requires a lot of cognitive energy and can be stressful to keep up.

“Autism is a part of us. It colours the way we think, interact with others and see the world throughout our life,” adds Kate.

“This isn’t something that can be turned off with masking. It simply gets pushed down to a level below that at which other people can see it. This ‘pushing down’ of our true self takes a lot of work.”

Moving away from the deficit model and embracing a strengths-based approach

While autism has historically been discussed from the deficit model or deficit-based approach, where the focus is on the difficulties and challenges experienced by autistic individuals, the neurodiversity movement and autism self-advocates have turned attention to the strengths that come with being autistic. Some experts now avoid calling autism a disorder, for example, and instead prefer “condition” or even “neurotype.”

“My brain isn’t broken. It’s just running on a different operating system,” says Kip Chow, an autistic educator. “There isn’t something inherently wrong with us. We’re just different.”

This paradigm shift has led to a re-evaluation of common autism therapies that some say promote compensatory behaviours and toward a stance of inclusivity, full acceptance and embracing difference. As a result of these changes, increased awareness about the various ways autism can present and updates to diagnostic criteria, autism diagnoses have greatly increased in recent years. In the UK alone, there was a documented 787 per cent exponential increase in autism incidence between 1998 and 2018.

Although a lot has been accomplished in reducing myths and misconceptions about autism and autistic people, there’s still a long way to go. Autistic people continue to confront a great deal of stigma, prejudice and misunderstanding, including when interacting with health-care professionals.

Further information and resources

Many late-diagnosed autistic teens and adults have taken to YouTube and other social media to talk about their experiences. They discuss life before and after diagnosis, the autism assessment process and various insights they’ve had throughout their journey.

Here are some resources to get you started:

Autism and late diagnosis: Q&A with two autistic adults

What women with autism want you to know

Behind the mask: Autism for women and girls

I'm autistic: Being diagnosed with autism at 23

Autism Q&A: Autism assessment in BC (covers how to seek assessment when over the age of 18)

ASD diagnosis for adults

Global prevalence of autism: A systematic review update

U.S. and Canadian autism rates on the rise, studies show


Do you have a question about this article or other BCCHR news?

Contact BCCHR Research Communications