Girls Likely to be Diagnosed with Autism When Older

A gender-sensitive comparative study has concluded that diagnosis of autism spectrum disorders (ASD) may happen later in girls than boys as the former may exhibit less severe symptoms.

The study used data obtained from Baltimore-based Kennedy Krieger Institute's Interactive Autism Network, a database of nearly 50,000 families affected by autism. Based on reported ages of nearly 10,000 children and additional data on symptoms of severity from another 5,103 individuals, researchers concluded that mean age of diagnosis in girls is higher than boys.

During their analysis of symptom severity, researchers found that girls were more likely to have problems with social cues while boys had extreme mannerisms that aided in earlier diagnosis.

"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," said Paul Lipkin the study's author.

The study calculated the mean age of diagnosis for pervasive developmental disorder, one type of ASD, in girls at 4 years compared to 3.8 years in boys. Diagnosis of Asperger's syndrome happened at 7.1 years on average with boys while the mean age for girls was 7.6 years. The study also noted an increased proportion of girls diagnosed with ASD during 2010-13 compared to 2006-09.