Any conversation about autism and the prevalence rates is incomplete without also mentioning the gender differences that occur across the spectrum. An understanding of the gender differences helps capture the traits and symptoms present in ASD in a more nuanced manner, and makes sure that we don’t miss the particularly subtle presentation that many females on the spectrum display. It also helps us understand why prevalence rates are so different with ASD, as there are about four times as many males diagnosed with ASD than females.
Recently, the largest study on gender differences in ASD was published in the United Kingdom. This study helped to support two theories that help explain the gender differences. One of the theories proposed that all women score higher on tests of empathy, while all men score higher on tests of systematization and analyzing. The other theory suggested that those with ASD, regardless of biological sex, will skew more “masculine” on tests of empathy and systematization.
This makes sense, given our knowledge of the strengths that those with ASD possess. Individuals with ASD tend to be strongly analytic, with a high attention to detail, and an adherence to rule-bound behavior. Additionally, while those with ASD may score lower on tests of empathy, this applies only to “cognitive empathy,” or recognizing and correctly interpreting others’ emotions. There is no evidence that suggests that those with ASD struggle with “affective empathy,” or caring about others.
Another theory behind gender differences within autism prevalence rates is about internalizing versus externalizing behavior. Boys tend to be diagnosed with autism earlier, as they tend to display more “externalizing” behavior – acting out, impulsivity, and aggression tend to be reasons for referral for young children with autism, and boys tend to display these types of behaviors more frequently than girls. Of course, girls, on or off the spectrum, can also demonstrate externalizing behaviors, it just tends to happen less frequently. Female children tend to “internalize” their behaviors, withdrawing socially, or experiencing anxious or depressed thoughts. Because these behaviors are not as apparent to the objective observer (and because they tend to be less disruptive in classrooms), girls may be referred for an evaluation later in life.
In addition to externalizing versus internalizing behaviors, girls on the spectrum often demonstrate compensatory behaviors around their peers, appearing to “camouflage” or blend in more than males on the spectrum may. They may look more neurotypical than they actually are. Girls also tend to have fewer restricted interests, and fewer repetitive behaviors, and the restricted interests that they do have tend to be more “socially acceptable.”
Even when gender differences are accounted for, there likely still is a higher rate of males on the spectrum compared to females. When reasons for referral are accounted for and males and females are evaluated on truly equal footing, there still appears to be a three times higher incidence rate of ASD in boys. This means that, compared to the 1995 study done in Denmark that estimated an 8 times higher incidence rate in boys as compared to girls, we are closer to accurate than ever before. Likely, the genetic and biological factors that contribute to our sex differences also is contributing to a true difference in prevalence rates, too.
We know that girls on the spectrum present differently, and we are pleased to have a team that understands the nuances and complexity that all genders present with. For more information, contact us! We can help.