The Implications of Sex Differences in Autism Spectrum Disorder

Faith and I have been kindred spirits ever since I began nannying her seven years ago. We, like most kids like to go to the mall, are suckers for a good selfie, and often chat about life.  

However, not everything with Faith is like a typical child. For instance, when we would want to go to the mall, she would often complain that it is "too noisy". Or when we were at the mall trying on clothes, she would say that her clothes are "too scratchy". And instead of going out in the community, she would prefer to play at home with her same dolls, like we did almost every day after school. Faith's insistence on sameness and odd requests, as I saw it, was just what made Faith, Faith, and didn't raise any red flags for me.  

However, my perspective on Faith's cravings for sameness and some of her apparently odd behaviours finally seemed to all make sense when she received an Autism Spectrum Disorder (ASD) diagnosis at the age of eleven. As a psychology student, I wondered why Faith received her diagnosis at the age of eleven when the typical age for an ASD diagnosis is four ("What Is Autism"). I was baffled why Faith received her diagnosis so late when she had a psychology student as her nanny, involved parents and teachers, and yearly doctor appointments. That was until I turned to academic literature and found out girls are often at a higher risk for being left undiagnosed, misdiagnosed, or diagnosed later and much less frequently than boys with ASD (Knutsen, Crossman, Perrin, Shui, & Kuhlthau, 2018). Currently, ASD affects one out of every 66 children in Canada. Males are four times more likely to receive an ASD diagnosis, despite expert's belief that the actual prevalence of ASD may be lower than popular approximations ("What Is Autism"; Knutsen, Crossman, Perrin, Shui, & Kuhlthau, 2018).   

So, why should we care?

Girls being underdiagnosed and diagnosed later isn't just a problem for Faith, but would help girls who are going undiagnosed and not receiving resources and support they need. For instance, if we look back at Faith's complaints regarding her clothes being "too scratchy" for her, had she been diagnosed earlier, she would be more likely to receive clinical services to help teach her ways to overcome the feelings of scratchiness of her clothes. Hence, if girls are going undiagnosed, then they are living without access to resources and available clinical interventions that are linked to impacting their quality of life.

Why are girls going left unseen? 

There is no one definite reason as to why girls are being left unseen; however, one going theory is that girl's symptoms and behavioural presentation of ASD are different than boys (Hull, Mandy, & Petrides, 2016).  For instance, to receive an ASD diagnosis, an individual must display behavioural deficits in their: 

1. social communication 
2. restricted and repetitive behaviours and interests (RRBIs) ("Diagnostic Criteria", 2019) 

This means that individuals must struggle with both domains, at a severe enough level that a doctor would diagnosis them. But if the presentation of  these behaviours is different amongst the sexes (and there has been a historic male bias as demonstrated by the discrepancy in the ratio between the sexes), then more awareness should be put on recognizing these differences. Currently, far more is known for sex differences in social communication deficits and much less is known about RRBIs, which may be linked as to why girls aren't being recognized with ASD as well as boys (Knutsen, Crossman, Perrin, Shui, & Kuhlthau, 2018). This is why the authors of the current paper being featured for discussion conducted a brief review of the RRBI profiles of females with ASD (Mcfayden, Antezana, Albright, Muskett, & Scarpa, 2019).

But first, what are RRBIs?

 ("Diagnostic Criteria", 2019)

RRBIs are behavioural symptoms that appear different in individuals but are clustered into four main diagnostic categories (i.e. the categories doctors use to diagnosis individuals with ASD). To best understand the different types of RRBIs that kids and adults with ASD present, I will be using Faith's RRBIs as an example. 

  

1.  Stereotyped Repetitive Motor Movements or Speech

 This category is utilized to describe behaviour that is overly patterned and repetitive, such as saying the same line from a movie over and over,  or playing with your dolls the exact same way every time. An example of this for Faith is when she would play with all her toys, she would meticulously line them all up during play and do this all throughout her play with them.

2. Insistence on Sameness and Inflexible Routines 

Insistence on sameness is generally categorized as a need for wanting to maintain rigid schedules and feeling distressed when changes are made to the routine. For example, Faith would prefer to perform the same afterschool routine every day, and changes to her routine would be distressing. 

3. Highly Restricted or Fixated Interests 

Remember for all kids these are different but are related to the individual's specific highly focused rigid interest. Faith has a fixated interest in dolls, as she only wants to talk about her toys and is not overly interested in anything else.  

4. Increased or Decreased Response to Sensory Input

This category means that the individual is highly responsive or unresponsive to sensory input, such as smells, hearing or touch. For example, when Faith would say her clothes are "too scratchy", that is her way of saying that she is more sensitive to her clothes than what someone typically without ASD would experience. 

So, what did the literature review find?

McFayden and colleagues examined multiple research articles and found that on the whole, prior research has actually demonstrated mixed results for the presentation of RRBIs in females relative to males. You may be thinking, "hmmm, this isn't really helpful". But in reality, mixed results are an indication that further research needs to be conducted. Moreover, these mixed findings may predict and represent how complex it is to measure these RRBIs. For instance, one study in their review found, in a large sample of youth, that males and females demonstrated differences in the frequency and severity of certain RRBIs. This study found that boys expressed more stereotyped and restricted interests, yet, girls displayed increased behaviours related to insistence on sameness. These findings are fascinating in that they may predict that girls and boys show differences in their RRBIs. These predictions may link to why girls' RRBIs are not being recognized as easily. In spite of these potentially promising findings, other studies in their report observed no significant sex differences in young children in terms of RRBIs, demonstrating the need for more comprehensive studies in this growing research topic. One explanation that McFayden and colleagues offered for the inconclusiveness of their analysis was the effectiveness of the diagnostic tools. utilized in practice. They theorized that these tools may be linked to not being sensitive enough to assess a female's RRBIs comprehensively. 

Nevertheless, I am optimistic that the increased focus on differences in the behavioural presentation of ASD in the sexes is one positive step forward. These studies have the potential to help learn more about why girls are being underrepresented in diagnoses. By shining a light on the different behavioural presentations of ASD, girls like Faith will hopefully be diagnosed sooner and get the resources they need. Because in the end, ASD is linked to being variable between the sexes. 

Interested in reading the articles yourself, look here!

Diagnostic Criteria. (2019, August 27). Retrieved from https://www.cdc.gov/ncbddd/autism/hcp-dsm.html.

Hull, L., Mandy, W., & Petrides, K. (2016). Behavioural and cognitive sex/gender differences in autism spectrum condition and typically developing males and females. Autism, 21(6), 706–727. doi: 10.1177/1362361316669087

Knutsen, J., Crossman, M., Perrin, J., Shui, A., & Kuhlthau, K. (2018). Sex differences in restricted repetitive behaviors and interests in children with autism spectrum disorder: An Autism Treatment Network study. Autism, 23(4), 858–868. doi: 10.1177/1362361318786490

Mcfayden, T. C., Antezana, L., Albright, J., Muskett, A., & Scarpa, A. (2019). Sex Differences in an Autism Spectrum Disorder Diagnosis: Are Restricted Repetitive Behaviors and Interests the Key? Review Journal of Autism and Developmental Disorders. doi: 10.1007/s40489-019-00183-w

What Is Autism. (n.d.). Retrieved from https://www.autismspeaks.ca/about-autism/what-is-autism/.