Sex Differences in Autism Spectrum Disorder: An Examination of Developmental Functioning, Autistic Symptoms, and Coexisting Behavior Problems in Toddlers

Hartley, S.L., Sikora, D.M.

Journal of Autism and Developmental Disorders (2009). 39: 1715-1722.

Question: Do girls and boys have the same symptoms of ASD?

Background: Most children who receive a diagnosis of ASD are male, outnumbering females by 4:1. It is the symptoms usually seen in boys that are used to define the condition. However, it is possible that many more girls should receive the diagnosis but don't because their symptoms are not the same as boys. This study looked at whether or not girls and boys have the same symptoms and whether there is a difference in the severity of the symptoms. This might help explain why there is such a large difference in the number of boys with ASD compared to girls.

Participants: One hundred and ninety-nine children aged 18 to 47 months referred to an autism clinic during the years 2003 to 2007, 199 were diagnosed with an ASD. Of this sample, about 80% were boys and 20% were girls.

Setting: A medical hospital in the northwest United States.

Design: This was a comparison study of young boys and girls who had been diagnosed with ASD.

Methods: Test scores and parent reports were used to determine if there were differences between male and female children recently diagnosed with ASD. The

Outcome Measures: Tests of everyday living skills, cognitive and motor development, and autism symptoms, were administered to all the participants. Their parents also reported on their child's behavior and mood.

Main Results: Most of the tests results were similar for boys and girls, with some exceptions. Girls had more problems with communication and tended to have greater difficulty with sleep and anxiety and low mood. Boys tended far more than girls to engage in restricted, stereotyped and repetitive behaviours.

Conclusion: Girls and boys with a diagnosis of ASD share most of the symptoms that characterize that condition. However, there are differences that could create unique challenges for families. Girls have more problems with communication, sleep, and mood problems. Boys are more likely to show repetitive and stereotyped behaviors.