Autism Presentation in Females

“Girls and boys with autism differ … and their brains are patterned in ways that contribute differently to behavioral impairments.” — Dr. Vinod Menon, PhD.

Did you know that Autism is more common in males than females? Research shows that prevalence of diagnosed ASD in males compared to females is a ratio of approximately 4:1, a common statistic in many countries. It is also not uncommon for many females to be formally diagnosed at a later age as compared to males (Rudy, 2023). 

Research has found differences in typical symptoms and presentation between the sexes, and typically, females with Autism often need to present more or more severe symptoms to get officially diagnosed with ASD. Autism is diagnosed by the DSM-5 (APA, 2022) based on criteria of observable behaviour in two main areas: social interaction deficits, and restricted/repetitive behaviour. Additionally, these behaviours have to be significant enough to limit and impair their daily functioning, according to the last criteria in the DSM. 

Biology of Autism in Females 

The lower presentation or official diagnosis of Autism in females may be owed to the “Female Protective Effect” (Robinson, 2013). Put simply, this means that “females accumulate more risk than males before being ascertained (confirmed) as ASD cases” (Wigdor et al., 2022). 

In essence, the biology of females ‘protects’ them by making it so that more differences in their genes are required before girls reach the specific threshold that causes sufficient impairment in their daily functioning to be considered as having ASD. This higher genetic resistance, however, also means that when enough risk factors in a female do accumulate to cross the threshold to be identified as Autism, it would likely be significantly more than what their male counterparts would require to reach the same diagnosis. 

A paper by Dworzynski et al. (2012) found that girls who were diagnosed with Autism often showed more additional problems in intellect and behaviours than other girls who were not diagnosed, but had similar levels of ASD traits. This is possibly owing to the larger amount of genetic risk factors accumulated. Compared to boys, girls diagnosed with Autism often had lower IQ and were more severely affected, likely due to the same reason. Hence, subtler or less severe forms of ASD in girls are less likely to be noticed or diagnosed, and only girls who are “more neurodivergent”, are officially diagnosed to have ASD. 

Social Interaction

Girls with ASD have also been found to be more likely to try “camouflaging” or “masking” in social situations, a coping strategy where they hide traits and tendencies of their ASD in an attempt to fit in with social expectations and appear socially competent (Hull, 2017; Hull, 2020a, Hull 2020b). This might be due to more desire to form friendships as compared to boys with ASD. Examples of camouflaging include suppressing idiosyncratic, out-of-the-norm behaviours, forcing themselves to show “appropriate” facial expression and eye contact — imitating and memorising acceptable social behaviours (Head, 2014). Hence, they have less noticeable differences and may not necessarily meet the social interaction criteria mentioned in the DSM. 

A study also found that girls with ASD generally have higher levels of sociability than boys with ASD, but lower than typically developing, neurotypical girls. However, females with ASD displayed a similar rating of sociability when compared with males who were neurotypical (Head, 2014). This may be the reason why when assessed, many girls who have Autistic traits but not severe impairments are able to “fly under the radar” and are not diagnosed. 

Research by Hiller et al. (2014) identified a trend whereby females with ASD were more likely to be able to initiate friendships and subsequently struggle maintaining them, while males were more likely to have difficulty with both. Given that the criterion for Autism diagnoses includes social initiation but not social maintenance, this difference in trait presentation may be part of why the number of diagnoses for girls is lower than that for boys. 

This leads to females with ASD getting misdiagnosed or diagnosed late, affecting the amount of support they receive in their early and developmental years. 

Restricted and Repetitive Behaviours 

Studies find that girls, in general, display less restricted and repetitive behaviours (RRB) as compared to boys. A study by Stanford University identified the cause of this to be differences in the brain structure of girls and boys with ASD. Notably as RRB tends to be the most noticeable characteristic that indicates possibility of ASD, this means that girls with less explicit RRB are not as likely to get diagnosed with Autism (Supekar & Menon, 2015). One of the authors stated, “[girls’ and boys’] brains are patterned in ways that contribute differently to behavioural impairments” (Digitale, 2015), as such.

Hiller et al. (2014) also found that in general, a majority of Autistic boys’ interests revolved around similar things (e.g. screens/devices, vehicles etc.), while the majority of the girls’ interests were categorised under “random”, meaning that they tended to be specific to the individual itself. Other studies found that autistic girls’ interests might also be ones that were ‘expected’ of girls their age, such as fashion or animals, which seem typical, but their interest in the topic would be significantly more intense than their neurotypical peers. This difference and variation in observed interests may make it harder for it to be identified as atypical or a “fixation” that can be a sign of ASD.  

Hence, using a diagnosis criteria that is based more heavily on the typical characteristics of males with ASD often leads to failure to diagnose females with ASD. Often, girls who display some characteristics of ASD are likely to get diagnosed with another disorder instead since they do not fully meet the criteria of ASD. 

What Next? 

Currently, the prevalence of diagnosed ASD in males compared to females is 4:1. However, this number might be a misrepresentation of actual statistics of individuals with Autism. As of now, research into sex differences in Autism presentation is developing and evolving constantly. 

Hopefully, this can lead to the development of more specific diagnosis tests which take into account differences and biases between males and females both on a genetic and social level to help identify females with Autism at an earlier stage and provide them with the interventions and support they need. 

Written by: Kai Sin

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