Girls with autism tend to be diagnosed later than boys, largely because they can present with different characteristics than those classically related to autism. This means that they may not receive the supports they need.
Researchers at Flinders University have found that under-detection of autism in girls may be partly driven by differences in the way they typically present compared to boys. In addition, clinicians have a restricted conceptualisation of how autism can be expressed, often using tools designed around a male presentation.
"Tools currently being used to measure ASD (Autism Spectrum Disorder) traits are based on research based on male participants, meaning that they are not sensitive to how girls present," says lead researcher Dr Joanna Tsirgiotis, from the College of Education, Psychology and Social Work at Flinders University.
"We need to better understand the unique challenges of girls so that we can improve our diagnostic assessment processes, ensuring they are appropriate for them."
Dr Tsirgiotis says the research demonstrated that autistic females may have less obviously unusual intense interests and fewer repetitive behaviours, and are often highly socially motivated and eager for friendships, unlike what is often assumed about children with autism.
In addition, females often had better imaginative and social mimicry skills which may allow them to copy the behaviours of others and therefore camouflage their difficulties, resulting in diagnosis being overlooked.
"This is important because without a diagnosis, they likely will not receive the support that they may need," says Dr Tsirgiotis.
To investigate specific behaviours in which differences lie, the Flinders researchers analysed profiles of 777 children using two commonly used diagnostic tools measuring ASD traits. This provided insight into how ASD presentations may differ between diagnosed male and female children.
They found that differences between boys and girls identified in this study, both in symptom type and severity, may render the female presentation of ASD less recognisable to referrers, such as parents and teachers, and clinicians tasked with assessment.
"Girls tend to engage in less obviously neurodivergent behaviour and this can add murkiness to the diagnostic picture. If we don't have a clear idea of ASD in girls, their characteristics can be misinterpreted as anxiety, quirkiness or even as 'normal' behaviour," says Dr Tsirgiotis.
If the female presentation is less recognisable, ASD diagnosis may be delayed or overlooked entirely.
In another study, the Flinders University researchers looked at clinical judgement and decision making, finding that diagnosticians may be much less confident in autism assessment for girls - and they interpret ASD behaviours differently depending on the child's sex.
"Diagnosticians find it harder to assess girls because their difficulties are often more subtle in social environments, and they lack trust in our current assessment tools and criteria which are less than ideal in reflecting girls' experience of ASD," says Dr Tsirgiotis.
The researchers suggest that timely ASD diagnosis requires greater understanding of the unique challenges faced by autistic girls, and that assessing practitioners are aware of more subtle or alternate expressions of neurodiversity, adapting their assessment to what we are learning about autism in girls.
"In these studies, we identified several areas in which females may be more likely to present as typically developing, which may further compound under-detection and mean that the broader constellation of ASD difficulties is overlooked," says Flinders University's Professor Robyn Young, a co-author of the research.
"It is therefore critical that diagnosticians, referring clinicians and teachers are educated in these differences so that females' ASD may be detected in a timely manner."
The research - "Sex/Gender Differences in CARS2 and GARS-3 Item Scores: Evidence of Phenotypic Differences Between Males and Females with ASD" by Joanna Tsirgiotis, Robyn Young and Nathan Weber (doi: 10.1007/s10803-021-05286-0), and "A mixed-methods investigation of diagnostician gender expectancy bias and challenges in assessing females for autism spectrum disorder" by Joanna Tsirgiotis, Robyn Young and Nathan Weber (doi: 10.1007/s10803-021-05300-5) - has been published by the Journal of Autism and Developmental Disorders.
