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Clinicians and referrers need to need to be aware of non-classic ASD presentations and, in particular, the subtleties of autism in girls, writes Dr Joanna Tsirgiotis.
The importance of a timely diagnosis of autism spectrum disorder (ASD) is well known.
However, increasing evidence shows that ASD is different in girls, and this poses real challenges for timely referral and accurate assessment.
Indeed, robust sex differences have been found in every ASD diagnostic criterion, both in severity and in the manifestation of ASD characteristics.
So, considering girls for an ASD diagnosis is like trying to fit a square peg into a round hole if we don’t understand their presentations.
“She can’t be autistic, she’s too social”
Contrary to the classic understanding of ASD as being aloof and withdrawn, many autistic girls are extremely socially motivated and sometimes preoccupied with the desire to make friends.
There is often a pattern of brief friendships that end suddenly, a preference to play with boys, “bossiness” or passivity in play, and a tendency to become intense and possessive in friendships.
Girls’ social difficulties often emerge later in childhood when the social demands outweigh their skill level.
Until then, girls often get by using superficial social skills, such as mimicking others and camouflaging their unusual characteristics.
Autistic girls have also been shown to have better imagination than autistic boys, possibly enabling this social mimicry.
“She doesn’t have the stereotypical behaviours or obsessive interests!”
Girls’ repetitive behaviours are often more subtle and less strongly associated with autism (eg, spinning, hair twirling, and unusual speech mannerisms such as accent use).
Similarly, special interests are often less developmentally unusual and overlooked as being typical if not unpacked carefully.
For instance, I’ve assessed girls who have been preoccupied with learning the flute, Hannah Montana, and particular children at school – not unusual themes in and of themselves, but certainly far more intense and lasting years longer than their peers.
“She seems to be coping okay at school!”
Unlike autistic boys who tend to show their distress outwardly, girls are more likely to internalise by withdrawing or crying and are therefore less likely to raise teachers’ concerns.
However, wearing a social mask during the school day comes at a cost, often expressed via exhaustion and meltdowns at home.
So, there is often asymmetry in the degree of concerns raised by parents and teachers.
Given the differences in presentations, diagnosticians are much less confident in assessing girls for autism than boys.
Our recent studies have also found evidence of bias in how strongly ASD-related behaviours are linked with diagnosis for girls and boys.
Interestingly, when presented with identical case studies varying only by the gender of the child, diagnosticians had more difficulty with the female case and interpreted the girl’s ASD as more severe.
The use of psychometric tools
When we as diagnosticians are less confident in our clinical assessment, we turn to psychometric tools for validation.
But, given that autism is historically diagnosed more in boys than girls (about 4:1, but estimates up to 10:1 exist), our tools have been constructed based on research about boys.
That means that they are most sensitive to boys’ difficulties and do not adequately capture how girls tend to present.
We showed this in a recent article examining two commonly used tools: the Childhood Autism Rating Scale 2 (CARS2) and the Gilliam Autism Rating Scale 3 (GARS-3).
Similarly, studies using the Autism Diagnostic Observation Schedule (ADOS) have shown that autistic girls score lower overall and in particular domains such as repetitive behaviours and obsessive interests.
There is a limited number of psychometric assessment tools designed for girls, based on small samples, at this stage probably best used qualitatively with other measures: Questionnaire for Autism Spectrum Conditions (Q-ASC), modified for use in women (GQ-ASC).
The Camouflaging Autistic Traits Questionnaire (CAT-Q) is another useful tool to measure social compensatory behaviours and supplement assessment.
Finally, the Social Responsiveness Scale 2 (SRS-2) is one of the few tools with separate norms for girls.
The issue with current tools
The issue is that these tools have recruited diagnosed autistic girls from which the scores have been standardised.
It is possible that girls who most embody the female presentation are yet to be diagnosed, thus not included in standardising the tools, and therefore do not reach the clinically significant threshold.
Not having a diagnosis leads to limited, inappropriate or a complete absence of supports.
Many late diagnosed women have described feeling completely “alien” and “defective” trying to navigate a neurotypical world with a neurodivergent brain – and having no idea why.
Sadly, this is a perfect storm for developing anxiety and mood disorders and poor coping strategies, as well as unrelenting self-criticism that takes years of effort to reduce.
Where to from here?
The main task is to increase clinicians’ and referrers’ awareness of non-classic ASD presentations.
Assessors should invest in the concerns raised by parents even if these are not shared by others and conduct their own naturalistic observations across different settings.
We may need to accept a lower threshold of clinical significance in girls, with the awareness that gender norms and the pattern of difficulties shown by girls may have an impact on the how we perceive girls’ difficulties.
Finally, we await robust diagnostic tools standardised to the female ASD presentation.
Dr Joanna Tsirgiotis is a psychologist specialising in ASD assessment. Her PhD examined sex differences in ASD and underdiagnosis in girls through Flinders University. She is also a third-year medical student at the University of Queensland.
The statements or opinions expressed in this article reflect the views of the authors and do not necessarily represent the official policy of the AMA, the MJA or InSight+ unless so stated.
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