A leading U.K.-based autism researcher is raising the alarm about the potential that a vast number of girls and women with autism may be going undiagnosed, as a result of gender bias.

"We have a bias that autism is a male condition because of all the depictions of autism and all the research that is also very male-dominated," said Dr. Francesca Happé, professor of neuroscience and the director of the Social, Genetic & Developmental Psychiatry Centre at King's College London in England.

That's led to autism going undetected in potentially hundreds of thousands of autistic girls and women. As a result, these women may not be getting the help they need and deserve.

Kelly's story

Happé told Quirks & Quarks that overlooked female autistics tend to be "high functioning" and without intellectual impairments.

But most still struggle with things like social interactions, sensory information and behavioural problems that are frequently mistaken for other maladies, or simply ignored.

Montrealer Kelly Johnson has been living with autism unknowingly for over three decades until she was diagnosed recently. (Photo provided by Kelly Johnson)

Canadian Kelly Johnson lived with autism without knowing it for most of her life.

She's turning 38 this year, and lives in Montreal with her family. Johnson only got diagnosed with autism five years ago, though there were signs all along.

"I would have panic attacks, and what I didn't know was that my anxiety and panic attacks were actually being caused by sensory overload," she explained.

Lighting for her can feel oppressive. She doesn't like noise, and has a hard time telling when she's too cold or too hot.

The sensory overload caused by not being able to cope with these stimuli can cause what she calls a "meltdown."

Johnson did seek various kinds of help, including therapy, but they didn't really work. So she suffered in confusion and distress.

"I kind of blamed myself for these struggles because I didn't know where they were coming from," said Johnson. "I figured it must've been just me, because nobody else was having problems. I figured I was broken."

I figured it must've been just me, because nobody else was having problems. I figured I was broken. - Kelly Johnson

It wasn't until her son was diagnosed with autism that she began to see similarities in their struggles.

She visited an adult autism clinic and, at the age of 32, received an autism diagnosis.

Today, Johnson is a much happier person, because she understands herself — why she's the way she is — and is aware of the strengths, as well as the difficulties, of her condition.

Since her diagnosis, she has joined the board of Autism Canada and founded Completely Inclusive, a business consultancy focused on educating companies about disabilities.

Getting a handle on the numbers for female autism

In 2017, a group of researchers from University College London in the UK published an epidemiological study in an attempt to find the true male-to-female ratio in autism spectrum disorder (ASD). Autism is more common in males, but how much more common was a matter of some dispute.

Dr. Francesca Happé is a leading autism researcher based in the U.K. (King's College London)

The group reviewed 54 studies that included 14 million participants aimed at identifying individuals with autism.

But they found a discrepancy. Different methods predicted quite different numbers for the frequency of autism in women. The discrepancy came from how autism cases are identified in studies, said Dr. Happé.

Some studies simply compared numbers of individuals who had been diagnosed with autism. These studies found that there was about one autistic woman diagnosed for every four autistic men.

Another approach used active screening. Researchers would interview an entire cohort of people. and identify those who might have the condition and follow up with them later. This method captured people who hadn't been diagnosed, and revealed a previously unknown population of autistic women.

This study found a ratio of one autistic woman for ever three autistic men—a considerably higher ratio. This result suggested that there might well be hundreds of thousands of women who haven't been diagnosed.

The female face of autism

The root of the problem, however, comes down to the way autism studies in the past have largely excluded women, said Happé, which has led to misdiagnosis and underdiagnosis in women.

"It's not surprising that we're looking for the male stereotype of autism [in diagnostics]. What we think we know about autism is actually what we know about male autism."

We need to go out there into the general population and really study the natural history of this thing that we call autism. - Francesca Happé

She also pointed out that women tend to camouflage autism more than men,by copying a popular girl's social behaviour in class, for example — mimicking how she dresses, talks and moves.

This, and other coping strategies they employ, makes autistic girls harder to identify, especially if the diagnostic standard is male autistic behaviour.

To get better at spotting autism in girls and women, researchers and clinicians must take a more proactive approach, said Happé.

"We can't just look at those who are currently diagnosed, because that's going to be circular and we're not going to improve our diagnostic criteria to be sensitive to how autism might look different to women and girls." she said. "We need to go out there into the general population and really study the natural history of this thing that we call autism."