It’s been a long-held understanding that boys appear to have autism at higher rates than girls; 4:1 is a ratio that often gets tossed around. However, there’s less clarity when you begin to wonder, “Why?” It would seem that some fault lies with diagnosis, some with studies that just can’t be generalized, some with genuine neurological and cognitive differences, and maybe even some with implicit gender biases. What is known for sure, is that ratio is not reflective of the reality of autism. Girls with autism are passed over.

A Mistake We Can’t Shake

The original studies of Autism and Asperger’s characterized the disabilities by “a lack of empathy, little ability to form friendships, one-sided conversations, intense absorption in a special interest, and clumsy movements.” And while this description seems to pinpoint the key challenges associated with a disability affecting social and communication skills, it has one fatal flaw: the observation was made solely about a group of boys. In fact, when Hans Asperger first described “autistic psychopathy,” he was operating under the assumption that girls were entirely unaffected by the condition. It can be easy to criticize in hindsight, but it becomes more difficult when you acknowledge that modern science isn’t immune. The diagnostic criteria for Autism Spectrum Disorder (ASD) used today is derived largely from studies that exclusively use boys. When you consider that this a disorder characterized by behavioral patterns, the problem becomes apparent upon realizing that boys and girls on the spectrum behave differently from one another.

This has the unintended consequence of under- and misdiagnosis of girls with autism, especially those that are on the higher-functioning end of the spectrum. Those who receive an early diagnosis usually express a severe intellectual disability and display the more disruptive behaviors typically associated with autism. High-functioning girls with autism may undergo a series of faulty diagnoses that only exacerbate feelings of loneliness or despair. Misdiagnoses often include ADHD, OCD, Bipolar Disorder, and even anorexia.

The Brain and Behavior with Autism

Compiling evidence suggests that autism manifests itself differently in girls, both neurologically and behaviorally.

Preliminary research being conducted jointly by Harvard University, The University of California, Los Angeles, and the University of Washington suggests that the neurological processes associated with understanding social information in children with autism simply doesn’t apply to girls. A lead scientist of the study is quoted as saying, “Everything we know to be true about autism seems to only be true for boys.” Girls with autism process social information differently than boys on the spectrum. Developmentally, they can be compared to neurotypical boys of their same age, and they show a slight decrease in activity in areas of the brain associated with social behaviors. While comparable to neurotypical boys, their abilities are reduced from those of neurotypical girls. On the basis of brain activity alone, these girls would not be considered on the spectrum if they were being held to the same standard as boys, a practice that current diagnostic procedures enforce.

These differences can be observed and measured behaviorally as well. A small study conducted by Jane McGillivray and her colleagues found a similar discrepancy when measuring friendship quality and empathy in girls and boys with autism. On both measures, autistic girls scored as high as neurotypical boys of the same age. But they still scored lower than typically developing girls.

And herein lies the difficulty: girls with autism don’t appear to be struggling because their behavior is not unexpected when looking at child behavior holistically. Some children are loud and outgoing, some are a little shy–we quite reasonably don’t expect all children to behave the same way or have the same social habits. It’s becoming more apparent that we can’t look at child behavior holistically because that would ignore the different expressions of autism we see in boys and girls.


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