Cases of autism are on the rise, with diagnoses in the US jumping 175% between 2011 and 2022.
But while this condition has historically been thought to affect men and boys more often, new research shows otherwise.
A large study paints a different picture, showing that young girls in particular are being left behind when it comes to diagnosis and treatment.
Boys are often diagnosed with autism spectrum disorder, a complex group of developmental conditions characterized by repetitive behaviors and difficulties with social interactions, at higher rates throughout childhood.
However, by adulthood, the ratio of men and women being diagnosed is equal.
But, according to a study analyzing the medical records of more than 2.7 million Swedes, fewer girls aren’t being diagnosed; they’re just being diagnosed later in life.
While males were diagnosed at much higher rates during childhood than females, the ratio leveled out by age 20.
This suggests that autism isn’t a predominantly male condition; it just takes longer for girls to be properly diagnosed.
“This male-to-female ratio may therefore be substantially lower than previously thought, to the extent that, in Sweden, it may no longer be distinguishable by adulthood,” study lead and medical epidemiologist Caroline Fyfe of the Karolinska Institute in Sweden said.
Why remains unclear, although a few ideas are shared in the study.
Signs of autism could present differently in girls than in boys, especially when they’re younger.
Researchers at Stanford University School of Medicine previously found that autistic girls display less repetitive and restrictive behavior than boys.
Meanwhile, parents, caregivers and healthcare professionals might expect that women are less likely to be autistic (based on previous data) and could develop a bias that prevents them from recognizing the traits.
This study adds to growing evidence suggesting autistic women and girls are being let down by current systems of diagnosis and treatment.
Previous research has also shown that there are critical differences in the brains of girls diagnosed with autistic disorders, finding that certain regions of the cortex were thicker.
And despite decades of research, the exact causes are relatively unknown.
Researchers at NYU Langone Health have said autism diagnoses can often be chalked up to genetics, exposure to pollution and access to healthcare.
The treatment of a spectrum disorder can vary, meaning some people require extra support, which an earlier diagnosis can help address specific symptoms.
