Age at autism diagnosis differs between boys, girls
Girls are diagnosed with autism spectrum disorder (ASD) later than boys, possibly because females exhibit less severe symptoms, according to a study to be presented Tuesday, April 28 at the Pediatric Academic Societies (PAS) annual meeting in San Diego.
To study gender differences in age at diagnosis and compare symptom severity between boys and girls, researchers at the Kennedy Krieger Institute in Baltimore, Md., analyzed data from the Institute's Interactive Autism Network. This online registry includes almost 50,000 individuals and family members affected by ASD who work with researchers to better understand the nature of the disorder. In the registry, age of first diagnosis was available for 9,932 children, and 5,103 had completed the Social Responsiveness Scale, which identifies the presence and severity of social impairment.
In the data review, researchers found girls were diagnosed with pervasive developmental disorder, an ASD impacting the development of many basic skills, at a mean age of 4 years compared to 3.8 years for boys. This also was the case with girls diagnosed with Asperger's syndrome; girls were diagnosed at a mean age of 7.6 years for the condition, which affects language and behavioral development, vs. 7.1 years for boys.
In addition, they found girls struggled more with social cognition—the ability to interpret social cues. Meanwhile, boys had more severe mannerisms such as repetitive behaviors like hand flapping, as well as highly restricted interests. Older boys, ages 10-15, also had more difficulties with the ability to recognize social cues and use language in social situations.
"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," said Paul Lipkin, MD, FAAP, study author and director of the Interactive Autism Network at Kennedy Krieger. "We must determine if the less recognizable symptoms in girls are leading not only to delayed diagnosis, but also under-identification of the condition."
Researchers also saw an increase in the proportion of girls who were diagnosed with ASD in 2010-2013 when compared to 2006-2009. Dr. Lipkin, a neurodevelopmental pediatrician who also serves as director of medical informatics at Kennedy Krieger, believes this increase may be due to growing public awareness and that screening methods and treatment strategies may need to be modified to meet the needs of each gender.