Story at a glance
- Historically, females have been underrepresented in research on autism.
- A new study suggests the reason behind this could be use of a screening tool that tends to exclude autistic females.
- The gender gap could hinder development of effective interventions for women and girls and result in underdiagnosis.
Women tend to be excluded from studies on autism and this disparity can hinder accurate diagnoses and the development of useful interventions for both women and girls.
That’s according to researchers at the Massachusetts Institute of Technology (MIT) who carried out an investigation on a commonly used screening test, the Autism Diagnostic Observation Schedule (ADOS). The ADOS is used to confirm autism diagnosis among patients prior to study enrollment based on social interaction, communication, play, and repetitive behaviors.
Researchers found that in a sample of 145 adults who already had a preexisting community diagnosis of autism — received from a general medical practitioner, neuropsychologist, and/or a mental health provider — the tool excluded autistic females at a rate over 2.5 times higher than that of autistic males.
Comparing the sex ratios in this sample to larger publicly available datasets on over 40,000 adults revealed community diagnoses resulted in significantly more equal sex ratios compared with confirmatory diagnostic assessments like ADOS, authors wrote in the journal Autism Research.
Although males are four times as likely as females to be diagnosed with the condition, recently experts have called for more female representation in studies which in the past have included small female sample sizes or excluded the patients altogether.
Because of this, female diagnoses could be missed altogether and an already small pool of study subjects is further reduced.
“I think the findings favor having a more inclusive approach and widening the lens to end up being less biased in terms of who participates in research,” said co-author John Gabrieli, the Grover Hermann Professor of Health Sciences and Technology and a professor of brain and cognitive sciences at MIT in a statement.
“The more we understand autism in men and women and nonbinary individuals, the better services and more accurate diagnoses we can provide.”
Doctors can use a variety of screening tests to diagnose individuals with autism spectrum disorders, but use of these measures is not required.
The ADOS test was originally developed using a mainly male sample, researchers noted, which may explain why it excludes so many females. Thus, an implicit bias in how autism is defined may be present, Gabrieli said.
Female patients with autism tend to differ from males particularly when it comes to symptoms involving social communication.
“The goal is that research should directly inform treatment, therapies, and public perception,” added co-author Anila D’Mello, a former MIT postdoc and an assistant professor at the University of Texas Southwestern.
“If the research is saying that there aren’t females with autism, or that the brain basis of autism only looks like the patterns established in males, then you’re not really helping females as much as you could be, and you’re not really getting at the truth of what the disorder might be.”
The team plans to conduct more research on sex- and gender-based differences in autism and hope to expand gender categories to include nonbinary and transgender patients.