In the United States, 1 in 42 boys are diagnosed with autism spectrum disorder (ASD), but only 1 in 168 girls are diagnosed with the same. This disparity may be because ASD is not the same in boys and girls, according to a study from Baltimore’s Kennedy Krieger Institute. The study found that the symptoms of ASD differ between boys and girls with ASD. The results also show that girls tend to be diagnosed with ASD later than boys. The findings have implications for how clinicians identify ASD in girls.
Data for the study came from the Interactive Autism Network (IAN), an online registry of about 50,000 people with ASD or related to people with ASD. From the IAN, researchers identified an age of diagnosis for 9,932 children. Of that group, 5,103 had information on the presence and severity of ASD, which were determined with the Social Responsiveness Scale.
There were significant differences between the symptoms of ASD between boys and girls. The results showed that girls struggle to interpret social cues. However, among older children aged 10 to 15, boys struggle more with social cues than girls. Boys aged 10 to 15 also struggled more with language in social situations. Boys overall were more likely than girls to have limited interests and to exhibit severe mannerisms, including repetitive behaviors.
The researchers also found a difference in the age of diagnosis between boys and girls. Among children diagnosed with pervasive developmental disorder (PDD), girls were diagnosed at age 4 and boys were diagnosed at age 3.8. Among children diagnosed with Asperger’s syndrome, girls were diagnosed at age 7.6 and boys were diagnosed at age 7.1. These differences are small, but these data are averages from thousands of people with ASD, which suggests a significant gap in the age of diagnosis.
Dr. Paul Lipkin, director of the Interactive Autism Network at Kennedy Krieger commented that “This and other studies suggest that girls with ASD, as well as perhaps older women with this disorder, differ from males in key symptoms and behaviors, particularly around social interactions. We must determine if the less recognizable symptoms in girls are leading not only to delayed diagnosis, but also under-identification of the condition.”
This research was presented at the Pediatrics Academic Societies Annual Meeting in San Diego.
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